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Solar Power Satellites

August 1981

NTIS order #PB82-108846

Library of Congress Catalog Card Number 81-600129

For sale by the Superintendent of Documents,U.S. Government Printing Office, Washington, D.C. 20402

Foreword

The energy difficulties the Nation has faced over the past decade have givenrise to an increased awareness of the potential long-term, inexhaustible, orrenewable energy technologies. This assessment responds to a request by the HouseCommittee on Science and Technology for an evaluation of the energy potential ofone of the most ambitious and long-term of these technologies, the solar powersatellite (SPS).

In assessing SPS, OTA has taken into account the preliminary nature of SPStechnology by comparing four alternative SPS systems across a broad range ofissues: their technical characteristics, long-term energy supply potential, interna-tional and military implications, environmental impacts, and institutional effects.The SPS options are also compared to potentially competitive future energytechnologies in order to identify how choices among them might be made. In addi-tion, OTA developed a set of Federal research and funding options to address thecentral questions and uncertainties identified in the report.

We were greatly aided by the advice of the SPS advisory panel, as well as by theparticipants in three specialized workshops: one on alternative SPS systems, one onpublic opinion, and another on competing energy supply technologies. The contri-butions of a number of contractors, who provided important analyses, and ofnumerous individuals who gave generously of their time and knowledge, aregratefully appreciated.

Director

. . .Ill

Solar Power Satellites Advisory Panel

Paul CraigUniversity of California

S. David FreemanTennessee Valley Authority

Eilene GallowayConsultant

Karl GawellSolar Energy Research Institute

Peter G laserArthur D. Little, Inc.

John W. Freeman, Jr., ChairmanRice University

Kenneth BillmanElectric Power Research Institute

Hubert P. DavisEagle Engineering

Henry M. FoleyColurnbia University

Ken BossongCitizens Energy Project

Ben BovaOMNI

Clifflyn BromlingBromling and Associates

Mike CasperCarlton College

Earl CookTexas A&M

John P. Schaefer, ChairmanUniversity of Arizona

Jerry GreyAmerican Institute of Aeronautics

and Astronautics

Grant HansenSDC Corp.

Russell HensleyAetna Life & Casualty

Maureen LambConsultant

J. C. RandolphUniversity of Indiana

Workshop on Technical Options

John J. SheehanUnited Steelworkers of America

Graham SiegeITennessee Valley Authority

Robert UhrigFlorida Power & Light

Frank von HippelPrinceton University

Charles WarrenAttorney

Joe G. Foreman John D. G. RatherNaval Research Laboratories The B.D.M. Corp.

Jerry Grey Fred SterzerAmerican Institute of Aeronautics RCA Laboratories

and Astronautics Frank von HippelAbraham Hertz berg Princeton University

University of Washington Gordon WoodcockBoeing Aerospace Co

Workshop on SPS Public Opinion Issues

Leonard DavidNational Space Institute

Chris E If ringOffice of Technology Assessment

Joe ForemanNaval Research Laboratories

Jerry GreyAmerican Institute of Aeronautics

and Astronautics

Skip LaitnerCommunity Action Research Croup

of Iowa, Inc.

Maureen LambConsultant

Jenifer RobinsonOffice of Technology Assessment

Louis SlesinNatural Resources Defense

Council, Inc.

Workshop on Energy Context of Solar Power Satellites

Clark Bullard, ChairmanUniversity of Illinois

Charles BakerArgonne National Laboratory

Piet BosElectric Power Research Institute

Glen BrandvoldSandia National Laboratory

Clifflyn BromlingBromling & Associates

Paul CraigUniversity of California

Peter DrummondMcDonnel-Douglas Astronautics

Lessly GoudarziInternational Energy Associates,

Limited

Kenneth HubArgonne National Laboratory

Jerry KaraganisEdison Electric Institute

John LamarshPolytechnic Institute of New York

Kenneth LingApplied Solar Energy Corp.

William MetzConsultant

David MorrisInstitute for Local Self Reliance

James MoyerSouthern California Edison

Larry RuffBrook haven National Laboratory

Frank von HippelPrinceton University

Gordon WoodcockBoeing Aerospace Co.

iv

Solar Power Satellites Project Staff

Lionel S. Johns, Assistant Director, OTAEnergy, Materials, and International Security Division

Richard E. Rowberg, Energy Program Manager

David Claridge, Project Director (until January 1980)

Ray A. Williamson, Project Director (from January 1980)

Stefi Weisburd Adam Wasserman

Administrative Staff

Marian Grochowski Lisa Jacobson Lillian Quigg

Edna Saunders Yvonne White

Contributors

Clifflyn Bromling Alan Crane

Arlene Maclin William Metz

Contractors and Consultants

Eric Drexler International Energy Associates, Ltd.

John Furber David MorrisMark Gersovitz Institute for Local Self Reliance

Princeton University Barry SmernoffJerry Grey Smernoff & Associates

OTA Publishing Staff

John C. Holmes, Publishing Officer

John Bergling Kathie S. Boss Debra M. Datcher Joe Henson

Acknowledgments

OTA thanks the following people who took time to provide information or to review part or all of thestudy.

Martin Abromavage, Argonne National LaboratoryEdwin Beatrice, Letterman Army Institute of

ResearchRichard Beverly and William Brown, RaytheonTom Bull, Office of Technology AssessmentDaniel F. Cahill, U.S. Environmental Protection

AgencyDon Calahan, National Aeronautics and Space

AdministrationStephen Cheston, Georgetown UniversityStephen Cleary, Mfedical College of VirginiaP. Czerski, National Research Institute of Mother

and Child, PolandSteven Doyle, Office of Technology AssessmentLewis Duncan, Los Alamos Scientific LaboratoryWilliam Erickson, University of Mary/andHarold A. Feiveson, Woodrow Wilson School,

Princeton UniversityZorach Glaser, Bureau of Radiological HealthAnita Harlan, L-5 SocietyJohn Hooper, Sierra ClubWayne Jones, Lockheed Corp.Don Justesen, Veterans AdministrationFred Koomanoff, U.S. Department of EnergyJohn Logsdon, George Washington UniversitySimon V. Manson, National Aeronautics and

Space AdministrationRichard Marsten, Office of Technology

Assessment

Ernest L. Morrison, National Telecommunicationsand Information Administration

Fred Osborne, Sunsat Energy CouncilSteven Plotkin, Office of Technology AssessmentJohn Richardson, National Academy of SciencesMichael Riches, U.S. Department of EnergyDonald Rote, Argonne National LaboratoryCharles Rush, National Telecommunications and

Information AdministrationRichard Santopietro, U.S. Department of EnergyCarl Schwenk, National Aeronautics and Space

AdministrationRichard Setlow, Brookhaven National LaboratoryCharlotte Silverman, U.S. Public Health ServiceDavid Sliney, U.S. Army Environment/ Hygiene

AgencyMarcia Smith, Congressional/ Research ServiceGerald Stokes, Pacific Northwest LaboratoryA.R. Thompson, National Radio Astronomy

ObservatoryKosta Tsipas, Massachusetts Institute’ of

TechnologyPaul Tyler, Armed Forces Radiological Research

InstituteA.R. Valentine, Argonne National LaboratoryPeter Vajk, Science Applications, Inc.Margaret White, Lawrence Berkeley LaboratoryJohn Zinn, Los Alamos Scientific Laboratory

ContentsChapter

1.

2.

3.

4.

5.

6.

7.

8.

9.

Summary. . . . . . . . . . . . . . . . .

Introduction . . . . . . . . . . . .

Issues and Find

Policy Options.

Alternative Systems

ngs . . . . . . .

. . . . . . . . . . . .

for SPS . .

SPS inContext. . . . . . . . . . . .

The International Implications

Environment and Health. . . . .

Institutional Issues . . . . . . . . .

Page

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

of Solar Power Satellites . . . . . . . . . . . . . . . 145

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 227

A.B.c.D.E.

Alternatives to the Reference System Subsystems . . . . . . . . . . . . , . . . . . . . . . . 265Decentralized Photo voltaic Model . . . . . . . . . . . . . . . . . . . . . ................269Global Energy Demand Forecasts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ...271Environment and Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......275Examples of international Cooperation . . . . . . . . . . . . . . . . . . . . . . . . .........289

Acronyms, Abbreviations, and Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ....293

Chapter 1

ContentsPage

Current Status . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Energy Context . . . . . . . . . . . .

International and Military Imp

Systems and Costs. . . . . . . . . .

Public Issues. . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

ications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Environment and Health . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Space Context. . . . . . . . . . . . . . . .

LIST

Characterization of Four Alternative SPSSummaryof SPS Environmental Impacts

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

OF TABLES

Page

Systems. . . . . . . . . . . . . . . . . . . . . . . . . . 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

The solar power satellite (SPS) concepts en- ● Mirror transmission. Orbiting mirrorsvision using the constant availability of sun- would reflect sunlight directly to centrallight in space to generate baseload electricity locations on Earth. Terrestrial solar re-on Earth. Orbiting satellites would collect ceivers would convert the resulting 24-solar energy and beam it to Earth where it hour illumination to electricity.would be converted to electricity. Three major Since SPS would be a major future energyalternative systems have been suggested. system with diverse potential impacts and im-

● Microwave transmission. Solar radiationwould be collected in space and con-verted to microwaves. Microwave energywould be beamed to a receiving antennaon Earth where it would be converted toelectricity.Laser transmission. Solar radiation wouldbe collected in space and converted to in-frared laser radiation. The lasers wouldbeam power to an Earth receiver.

placations, this assessment of SPS technologyis interdisciplinary. It includes the study of SPSinteractions with society, the environment, theeconomy, and other energy systems. in addi-tion, because space is an international realmand energy is a global need, this assessmentalso undertakes a broad look at the interna-tional aspects of SPS.

CURRENT STATUS

Too little is currently known about the techni-cal, economic, and environmental aspects of SPSto make a sound decision whether to proceedwith its development and deployment. I n addi-tion, without further research an SPS demon-stration or systems-engineering verificationprogram would be a high-risk venture. An SPSresearch program could ultimately assure an ade-quate information base for these decisions. How-ever, the urgency of any proposed research ef-fort depends strongly on the perception of fu-ture electricity demand, the variety and cost ofsupply, and the estimated speed with whichthe major technical and environmental uncer-tainties associated with the SPS concept canbe resolved. For instance, if future demandgrowth is expected to be low it may not be nec-essary to initiate a specific SPS research pro-gram at this time, especially if more conven-tional electric-generating technologies remainacceptable. If this is not the case or if demandgrowth is expected to be high, SPS might beneeded early in the 21st century, and a timelystart of a research effort would be justified.

Should it be decided not to start a dedicatedSPS research effort now, it may be desirable to

designate an agency to track generic researchwhich is applicable to SPS, to review trends inelectricity demand, and to monitor the prog-ress of other electric supply technologies. Sucha mechanism could provide the basis for peri-odic assessment of whether to begin an SPS re-search program. Information relevant to SPScould be derived from other research pro-grams, microwave bioeffects, space transpor-tation, laser, and photovoltaic developmentappear to be the most critical technical issues.However, it is unlikely that such “generic”research programs by themselves would ade-quately answer all of the high-priority ques-tions on which SPS development decisions de-pend

If a dedicated SPS research effort is startednow, the level of effort chosen would, to alarge degree, determine the time it takes to ob-tain the information needed for a developmentdecision. An effort set at $5 million to $10milIion per year could be sufficient to gatherthe minimum necessary information while min-imizing the risk of insufficient or untimely in-formation. A $20 million to $30 million peryear effort could gain the maximum necessary

3

4 ● Solar Power Satellites

Photo credit: National Aeronautics and Space Administration

Microwave concept

Photo credit: National Aeronaut/es and Space Administration

Mirrored concept

SOURCE: K. W. Billman, “Space Orbiting Light Augmentation Reflector EnergySystem: A Look at Alternative Systems,” SPS Program Review,June 1979.

information at the earliest possible time. Itreduces the risk of not generating enough in-formation in time to make an adequate devel-opment decision. Whatever the level, if a re-

Photo credit: Painting by Frank G. Ellis, Lockheed Missiles and Space Co.

Laser concept

search program is instituted, it should investi-gate those areas most critical to SPS eco-nomic, technical, and environmental feasibil-ity Particular attention should be given tostudying and comparing the various technicalalternatives; but the feasibility of SPS also ulti-mately depends on its social, political, and institu-tional viability. Thus, a research program shouldcontinue to explore these aspects of SPS devel-opment and deployment as well. The followingare the major stages such a program wouIdhave to go through:

SPS Program Steps

Concept feasibility stages Development stagesBasic research Systems engineeringComponent testing Demonstration satelliteConcept definition Deployment

Ch. 1—Summary ● 5

ENERGY CONTEXT

Even if it were needed and work began now,a commercial SPS is unlikely to be availablebefore 2005-15 because of the many uncertain-ties and the long Ieadtime needed for testing anddemonstration. Therefore, SPS could not be ex-pected to constitute a significant part of elec-tricity supply before 2015-25. By that time, theUnited States will be importing very littleforeign oil. Consequently, SPS cannot reduce ourdependence on imported oil in this century.However, if efficient electric vehicles or otherelectric end-use technologies are developed byabout 2010, electricity from SPS or othersources could substitute for synthetic liquidfuels generated from coal or biomass.

Along with other electric generating technol-ogies, SPS has the potential to supply severalhundred gigawatts of baseload electricalpower to the U.S. grid by the mid-21st century.However, the ultimate need for SPS and itsrate of development wiII depend on the rate ofincrease in demand for electricity, and theability of other energy supply options to meetultimate demand more competitively. SPSwould be needed most if coal and/or convent-ional nuclear options are constrained and if de-mand for electricity is high.

An aggressive terrestrial solar and conserva-tion program that could lead to an electricitydemand level of only 8 Quads electric (Qe)* in2030 (equal to current consumption) wouldmake the development of SPS and other largenew centralized generating technologies lessurgent in the United States. In any event, coalcould continue to fuel the greatest share ofU.S. electrical needs well into the 21st century,provided no barriers to its use become evident.Coal, conventional nuclear, terrestrial solar inits many forms, and geothermal usage could

*A Quad is equal to 1 quadrillion Btu. It is equivalent to theenergy contained in 500,000 barrels of oil per day for 1 year, andis also approximately the electric energy produced by a 33,500-MW generator running without interruption for a year As used inthis report, Quads electric (Qe) of demand refer to the energyequivalent of electricity at point of use Primary energy input atthe generating source of electricity IS somewhat more than threetimes these figures

satisfy the entire domestic electricity require-ment for demands totaling 20 Qe (2.5 timescurrent level) or less in 2030. If demand ishigher than 20 Qe, then presumably one ormore of the following, SPS, breeders, and/orfusion will be needed. Electricity demand willbe strongly affected by the degree that effi-cient technologies for using electricity can bedeveloped. Such technologies can have the ef-fect of lowering the overall cost of electricitycompared to competing energy forms.

If generation from coal on a large scaleproves to be unacceptable, domestic electricalconsumption of 8 Qe or less could still be metby nuclear, geothermal, and terrestrial solar(central pIant and onsite) technology. For de-mands up to about 20 Qe, SPS could competewith terrestrial solar, breeders, and/or fusionfor a share of the centralized baseload market.If electricity demand exceeds 20 Qe, it will bedifficult to satisfy that demand without vig-orous development of al I renewable or inex-haustible forms of generating capacity. Forthese higher demand levels, SPS, breeders, andfusion could all share in supplying U.S. elec-tricity needs. A 30 Qe (3.8 times current con-sumption) total demand wouId create a marketpotential for up to 6 Qe of SPS-delivered ener-gy (225,000-Mw-installed generating capacityat 90-percent capacity factor). *

Upper Range of Possible SPS Use* *Electric demand SPS capacity (CW]

in 2030 (Qe] With coal Without coal7 5 0 0-30

20.0 0-60 100-20030.0 100-200 100-200

*Current U.S. generating capacity is about 600,000 MW. Cur-rent demand represents about 45 percent of this capacity oper-ating 100 percent of the time,

**Coal is used as the swingfuel for our analysis because it hasthe largest resource base of any of the current forms of central-ized, electric generating technologies It is expected that conven-tional nuclear would be available but its smaller resource basewould prevent it from having the large effect on generation-mixchoices that coal does It is assumed that breeders, which wouldgreatly extend the nuclear fission resource base, would be com-parable to SPS and fusion in terms of its rate of market penetra-tion (ie, 5 to 10 GW/yr)

6 ● Solar Power Satellties

SPS is designed to provide baseload electric-ity. By contrast, except for ocean thermal ener-gy conversion, terrestrial solar electrical gen-eration is intermittent. Because our energyfuture will require a mix of baseload and inter-mittent generating technologies, without stor-age capability, terrestrial solar would not com-pete directly with SPS. However, the devel-opment of inexpensive storage, if achieved,could enable terrestrial solar electricity genera-tion in all its forms-wind, solar thermal, andsolar photovoltaics–to assume some share ofbaseload capacity.* These technologies are lesscomplex, have fewer uncertainties, and areconsiderably nearer to commercial realizationthan SPS. Furthermore, they have the flexibili-ty to be introduced into the electrical grid in

small increments as needed to meet demandincreases on a local scale.

Even if inexpensive storage is not available, on-site generating technologies could compete in-directly with SPS. Total need for baseloadpower will decrease if a significant portion oftotal electrical demand can be met by a com-bination of dispersed technologies such assolar photovoltaics, wind, and biomass at coststhat are competitive with centrally generatedelectricity. Low demand for centrally gener-ated electricity would consequently reducethe need to introduce new, large-scale elec-trical technologies such as SPS, except asreplacement capacity.

As an energy option for the first half of the 21stcentury, the potential electrical output anduncertainties of SPS are comparable to fusion.These energy options will proceed along dif-ferent development paths. Except for a lasersystem, the basic SPS technologies have beenproven technically feasible. Research wouldbe needed to develop low-noise microwavetubes; high-efficiency, low-mass photovoltaics;efficient continuous-wave lasers; low-massmirrors; and space construction and transpor-tation capabilities. Although the fusion com-munity is confident that fusion is feasible,“energy breakeven, ” the production of moreenergy than is put into the fusion process, has

*The percentage share of baseload capacity which would befeasible for these technologies to assume would depend on theirgeographical location and the time of year (see ch 6)

Photo credit: EPA-Documerica—Gene Daniels

Trojan nuclear powerplant on the Columbia Rivernear Prescott, Wash., 1972

Photo credit: Texas Power & Light

Martin Lake electric generating plant in east Texas

Ch. l—Summary ● 7

not been achieved. For both SPS and fusion, aneconomic generating plant would still have tobe developed and demonstrated.

Both energy options are designed to pro-duce baseload central station power in unitsfrom 500 to 5,000 MW. For both, development

cost is high. For fusion, much of the manufac-turing infrastructure for the balance of plant,i.e., other than the fusion device itself, is inplace. Most of the supportive infrastructurefor SPS, including the industrial plants and thetransportation system, would have to be de-veloped.

INTERNATIONAL AND MILITARY IMPLICATIONS

There could be important economic and politi-cal advantages to developing SPS as a multi-national rather than a unilateral system. These in-clude cooperation in establishing legal andregulatory norms, shared risk in financing theR&D and construction costs, improved pros-pects for global marketing, and forestallingfears of economic domination and militaryuse. Although a multinational effort wouldface inevitable organizational and politicaldifficulties, the strong potential interest ofenergy-poor, non-U. S. participants in increasedelectrical supplies could help make a multina-tional venture more feasible than a unilateralone by the United States. GIobal electricity de-mand may quadruple by 2030, and will be es-pecially strong in developing countries. West-ern Europe and Japan wouId be likely partnersfor a joint project. Depending on the size andexpense of the system used, a number of themore rapidly developing but less developedcountries might also be interested in partici-pating at lower levels of involvement.

The Soviet Union is carrying on an aggres-sive space program that may give them an in-dependent capacity to develop SPS, but littleis known about their long-range space orenergy plans. Real or perceived competition

SYSTEMS

The optimum SPS system has not been iden-tified. A National Aeronautics and Space Ad-ministration/Department of Energy (NASA/DOE) microwave reference system* was devel-

*See chs 3 and 5 for a description of the reference system

with the Soviet Union could spur a U.S. com-mitment to SPS.

The development of fleets of launch and trans-fer vehicles (for SPS), as well as facilities for livingand working in space, would enhance this Na-tion’s military space capabilities. Such equip-ment would give the possessor a large break-out potential for rapid deployment of person-nel and hardware in time of crisis, though fornonemergency situations the military wouldprefer to use vehicles designed specifically formilitary purposes. SPS itself could be used formilitary purposes, such as electronic warfare orproviding energy to military units, but is tech-nically unsuited to constitute an efficientweapon. Weapons-use of SPS would be prohib-ited by current bilateral and multilateraltreaties. The satellite portion of SPS is vulner-able to various methods of attack and interfer-ence but the likelihood of its being attacked isonly SIightly greater than for major terrestrialenergy systems. The military effects of SPS willdepend largely on the institutional frameworkwithin which it is developed; international in-volvement would tend to reduce the potentialfor use of SPS by the military sector,

AND COSTS

oped to provide a basis for review and analysisbut was not intended to represent the bestpossible system. An optimum system should beable to deliver power in smaller units (about1,000 MW or less), use smaller terrestrialreceivers, and cost less to develop than thereference system. Alternative systems may use

lasers or mirrors to transmit solar energy fromspace to Earth. Variants of the reference sys-tem or other completely different systems mayoffer certain improvements; each will need fullstudy before choosing a system for develop-ment.

Current overall cost estimates for the SPS andits major components are highly uncertain. Theassessments of up-front costs range from $40billion to $100 billion. The most detailed esti-mates have been made by NASA for the refer-ence design. These call for a 22-year invest-ment of $102.4 bilIion (1977 dolIars) (includingtransportation and factory investment costs) toproduce the first 5-GW satellite, with each ad-ditional satellite costing $11.3 billion. The

costs for most improvements to the referencedesign, or for alternative systems, are less cer-tain due to the less developed state of nonref-erence technology. Preliminary studies in-dicate that the total reference system costs arelikely to be significantly higher. On the otherhand, alternative systems may well be cheaperthan the reference system. The total costsestimated by NASA include major elements,such as space transportation and photovoltaiccells, whose development is likely to proceedregardless of SPS; these costs should not becharged solely to SPS. With the possible excep-tion of fusion, the up-front costs for SPS wouldbe significantly higher than competing base-Ioad electric generating systems. Apportioningthe various investment costs and management

Characterization of Four Alternative SPS Systems

ScaleSatellite size 55 km2 18 km2 5 km2 50 km2

Number of satellites 60 (300 GW total) Not projected Not projected 916 (810 GW total)Power/satellite 5,000 MW 1,500 MW 500 Mw 135,000 MWMass 5 x104 tonnes/satellite; 0.1 kW/kg Less mass than reference/O. 1 kW/kg Less mass than reference/O.05 kW/kg 2 x 105 tonnes mirror system 2 kW/kgLand use rectenna site 174 km2 (including buffer) 50 km2 0.6 km2 1,000 km2

x 60=10,440 km2

k m2 1 , 0 0 0 M W 35 33 1.2 7.4

Energy Electricity Electricity Electricity, onsite generation. Electricity, lightFairly centralized Less centralized Less centralized Highly centralized

23 mW/cm2 Gaussian distribution Unknown Unknown (10 mW/cm2 at edge) 1.15 kW/m2 (1 Sun)

AtmosphereTransmission Ionosphere heating might affect telecommunications Tropospheric heating might modify weather over smaller area; problems with clouds?Effluents Possible effects include alteration of magnetosphere (AR+), increased water content; LEO orbit, smaller size, smaller launch vehicles

formation of noctilucent clouds; ionosphere depletion

ElectromagneticInterference RFI from direct coupling, spurious noise, and harmonics, Impacts on communications,

satellites etc from 245 GHz Problem for radio astronomers (GEO obscures portion ofsky always) optical reflections from satellites and LEO stations WiII change the night sky

Bioeffects Microwave bioeffects midbeam could cause thermal heating, unknown effects of longterm exposure to low-level microwaves Ecosystem alteratlon? Birds avoid/attractedto beam?

If visible light IS used there may be problems Problem for optical astronomy, optical reflec-for optical astronomy if Infrared IS used may hens and Interference from beam changeIncrease airglow optical reflection from LEO night sky in vicinity of sitessatellite.

Direct beam ocular and skin damage ocular Psychological and physiological effects of 24-damage from reflections? Other effects? Birds hour illumination not known. Possible ocularflying through will burn up? If visible WiII hazard if viewed with binoculars? Ecosystembirds avoid? Ecosystem alterations? alteration

National securityweapons potential GEO gives a good vantage point over hemisphere Direct weapon: as ABM, antisatellite, aimed at Indirect: night illumination psychological–

terrestrial targets possible weather modification–Provides a lot of power m space platform for surveillance, jamming–

Indirect: power killersatellite, planes space platform

–Requires development of large space fleet with/military potential– Laser defend self, best, LEO more accessible

Vulnerability Satellites may need self defense system to protect against attack Less ground sites; a lot of mirrors-redun-

Size and distance strong defenses– dancy; individual mirrors fragile; ground sitesstil l produce power in absence of spacesystem

International Will require radio frequency allocation and orbit assignment LEO more accessible to U S S R and high-latitude countries, smaller parcels of energy makeSmaller parcels of energy make system more system more flexible

flexibleMeet environmental and health standards?

asmaller SOLARES systems, e g , IO GW/site would be possible and probably more desirableb$l02 billilon–NASA estimate+ncludes Investment CostscEstimates byArgonneNational Laboratory, Office of Technology Assessment, u.s. Congress

SOURCE Office of Technology Assessment.

10 . Solar Power Satellites

responsibilities between the public and privatesectors, and among potential international par-

ticipants, would be an essential part of SPS de-velopment.

PUBLIC ISSUES

Public opinion about SPS is currently notwell-formed. Discussion of SPS has been lim-ited to a small number of public interestgroups and professional societies. In general,those in favor of SPS also support a vigorous U.S.space program, whereas many of those who op-pose SPS fear that it would drain resources fromsmall-scale, terrestrial solar technologies. Assum-ing acceptance of a decision to deploy SPS,public discussion is likely to be most intense atthe siting stage of its development. Key issuesthat may enter into public thinking includeenvironment and health risks, land-use, mili-tary implications, and costs. Centralization inthe decisionmaking process and in the owner-ship and control of SPS may also be important.From the standpoint of public perceptions, thesiting of land-based receivers could be anobstacle to the deployment of SPS unless:

● the public is actively involved in the sitingprocess;

● health and environment uncertainties arediminished; and

• local residents are justly compensated forthe use of their land.

Offshore siting of receivers could minimizepotential public resistance to SPS siting.

Reference System —Rectenna/Washington, D. C., Overlay

SOURCE: Off Ice of Technology Assessment.

ENVIRONMENT AND HEALTH

Many of the environmental impacts associatedwith SPS are comparable in nature and magnitudeto those resulting from other large-scale terres-trial energy technologies. A possible exceptionis coal, particularly if CO2 concerns are provenjustified. While these effects have not beenquantified adequately, it is thought that con-ventional corrective measures could be pre-scribed to minimize their impacts. However,several health and environmental effects, whichare unique to SPS and whose severity and likeli-hood are highly uncertain, have also been iden-tified. These include effects on the upper at-mosphere from launch effluents and powertransmission, health hazards associated with

non ionizing radiation, electromagnetic inter-ference with other systems and astronomy, andradiation exposure for space workers. More re-search in these areas would be required beforedecisions about the deployment or devel-opment of SPS could be made. Little informa-tion is currently available on the environ-mental impacts of SPS designs other than thereference system. Clearly, environmentalassessments of the alternative systems will beneeded if choices are to be made between SPSdesigns.

Too little is known about the biological effectsof long-term exposure to low-level microwave

Ch. 1—Summary . 11


An artist’s concept of an offshore antenna that would receive microwave energy beamed froma large space solar power collector in geosynchronous orbit

radiation to assess the health risks associatedwith SPS microwave systems. The informationthat is available is incomplete and not directlyrelevant to SPS. Further research is criticallyneeded in order to set human-health exposurelimits. Currently, no microwave population ex-posure standard exists in the United States.The recommended limit for occupational ex-posure is set at 10 mW/cm 2 in the UnitedStates, 1,000 times less stringent than the pres-ent U.S.S.R. occupational standard. Public ex-clusion boundaries around the reference de-sign have been established at one one-hun-dredth of U.S. occupational guidelines. It is an-ticipated that future maximum permissibleU.S. occupational standards will be lower by afactor of 2-Io; population standards, if estab-lished, may well be lower than the occupa-

tional standards. Even more stringent micro-wave standards couId increase land require-ments and system cost or alter system designand feasibility. In Iight of the widespread pro-liferation of electromagnetic devices and thecurrent controversy surrounding the use ofmicrowave technologies, it is clear that in-creased understanding of the effects of micro-waves on living things is vitally needed even ifSPS is never deployed.

Exposure of space workers to ionizing radiationis a potentially serious problem for SPS systemsthat operate in geosynchronous orbit (CEO). Re-cent estimates indicate that the radiation doseof SPS reference system personnel in CEOwould exceed current limits set for astronautsand could result in a measurable increase in

12 Ž Solar Power Satellites

Summary of SPS Environmental Impacts

System component Occupational healthcharacteristics Environmental impact Public health and safety and safety—

Power transmissionMicrowave — bIonospheric heating could — bEffects of Iow-level —Higher risk than for .

disrupt telecommunications. chronic exposure to micro- public; protectiveMaximum tolerable power waves are unknown. clothing required fordensity is not known. — Psychological effects of terrestrial worker.Effects in the upper microwave beam as weapon. —Accidental exposure toionosphere are not known —Adverse aesthetic effects high-intensity beam in

—Tropospheric heating could on appearance of night sky. space potentially severeresult in minor weather but no data.modification.

—bEcosystem: microwave bio-effects (on plants, animals,and airborne biota) largelyunknown; reflected lighteffects unknown.

—b Potential interference withsatellite communications,terrestrial communications,radar, radio, and opticalastronomy.

Lasers —Tropospheric heating could —Ocular hazard? —Ocular and safetymodify weather and spread — Psychological effects of hazard?the beam. laser as weapon are

— Ecosystem: beam may possible.incinerate birds and —Adverse aesthetic effectsvegetation. on appearance of night

— bPotential interference sky are possible.with optical astronomy,some interference withradio astronomy.

Mirrors — bTropospheric heating —Ocular hazard? —Ocular hazard?could modify weather. —Psychological effect of

—Ecosystem: effect of 24- 24-hr sunlight.hr light on growing — b Adverse aesthictic effectscycles of plants and cir- on appearance of nightcadian rhythms of animals. sky are possible.

— bpotential interferencewith optical astronomy.

Transportation andspace operation

Launch and recovery —Ground cloud might polluteair and water and causepossible weather modi-

HLLV fication; acid rainPLV probably negligible.COTV —b Water vapor and otherPOTV launch effluents could

deplete ionosphere andenhance airglow. Result-ant disruption of com-munications and satellitesurveillance potentiallyimportant, but uncertain.

— b possible formation ofnoctilucent clouds instratosphere and meso-sphere; effects on climateare not known.

—Noise (sonic boom) mayexceed EPA guidelines.

–Ground cloud might affectair quality; acid rainprobably negligible.

—Accidents-catastrophicexplosion near launchsite, vehicle crash, toxicmaterials.

—b Space worker’s hazards:ionizing radiation(potentially severe)weightlessness, lifesupport failure, longstay in space,construction accidentspsychological stress,acceleration.

—Terrestrial worker’shazards: noise, trans-portation accidents.

Ch. 1—Summary ● 13

Summary of SPS Environmental Impacts—Continued

System component Occupational healthcharacteristics Environmental impact Public health and safety and safety

— bEmission of water vaporcould alter naturalhydrogen cycle; extent andimplications are not well-known.

— bEffect of COTV argon ionson magnetosphere andplasma-sphere could begreat but unknown.

—Depletion of ozone layerby effluents expected tobe minor but uncertain.

—Noise.

Terrestrial activitiesMining — Land disturbance

(stripmining, etc.).—Measurable increase of

air and water pollution.—Solid waste generation—Strain on production

capacity of galliumarsenide, sapphire, silicon,graphite fiber, tungsten,and mercury.

—Manufacturing —Measurable increase of

air and water pollution.—Solid wastes.

—Toxic material exposure. —Occupational air and—Measurable increase of water pollution.

air and water pollution. —Toxic materials exposure.— Land-use disturbance. —Noise.

— Measurable increase of —Toxic materials exposure.air and water pollution. —Noise.

—Solid wastes.—Exposure to toxic

materials.

Construction —Measurable land — Measurable land —Noise.disturbance. disturbance. —Measurable local

—Measurable local increase —Measurable local increase increase of air and waterof air and water pollution. of air and water pollution. pollution.

—Accidents.

Receiving antenna — bLand use and siting— — bLand use—reduced — Waste heat.—Waste heat and surface property value, aesthetics,

roughness could modify vulnerability y (less landweather. for solid-state, laser

options; more for referenceand mirrors).

High-voltage — bLand use and siting— — b Exposure to high intensity —bExposure to high

transmission lines — bEcosystem: bioeffects of EM fields—effects intensity EM fields—(not unique to SPS) powerlines uncertain. uncertain. effects uncertain.a

impacts based on SPS systems as currently defined and do not account for offshore receivers or possible mitigating system modifications.bResearch priority.

SOURCE: Office of Technology Assessment.


cancer incidence. However, there are a largenumber of uncertainties associated with quan-tifying the health risks of exposure to ionizingradiation. More research would be required toreduce these uncertainties and to identify andevaluate system designs and shielding tech-niques that would minimize risks at an accept-able cost. In addition, acceptable SPS radia-tion limits would have to be determined. IfCEO SPS systems are to be considered, anassessment of the health risks associated withspace radiation is a top priority.

The potential for interference with other usersof the electromagnetic spectrum could constitute

a severe drawback for the microwave option.Satellite communications and optical andradio astronomy would be seriously affected.The effects on radio and optical astronomywould be the most difficult to ameliorate. Theminimum allowable spacing between geosyn-chronous power satellites and geosynchronouscommunications satellites is not well-known.The optical interference effects of either themirror or laser transmission options would beof great concern to ground-based astronomers.Any of the SPS options would alter the ap-pearance of the nighttime sky. Some may findthis esthetialIy objectionable.

.

SPACE CONTEXT

The hardware, experienced personnel, and in-dustrial infrastructure generated by an SPS projectwould significantly increase U.S. space capabil-ities and, in conjunction with other majorspace programs, could lay the groundwork forthe industrialization, mining, and perhaps thesettlement of space. NASA is likely to play amajor role, especialIy in the initial stages of de-velopment. Non-SPS programs could be aidedby accelerated development of transportationand other systems; on the other hand, theycould be harmed by the diversion of funds and

attention to SPS. An SPS research and develop-ment program would be in accord with currentspace policy that calIs for peaceful develop-ment of commercial and scientific spacecapab i I i t i es

Given the current absence of long-term pro-gram goals for the U.S. civilian space program,it is difficult to predict the effects of an SPSproject on NASA plans or on private-sector ca-pabilities These effects will need to be care-fully considered.

Chapter 2

INTRODUCTION

Chapter 2

INTRODUCTION

As the United States and the world have be-gun to face the realities of living with a limitedsupply of oil and gas, and the political uncer-tainties that accompany impending scarcity,the search for reliable, safe means of using theradiant energy of the Sun has intensified. Solarradiation is already used in many parts of theNation for direct space heating and for heatingwater. It can also produce electricity by photo-voltaic and thermoelectric conversion. How-ever, nearly all terrestrial solar collectors andconverters suffer from the drawbacks of theday-night cycle. On Earth, sunlight is onlyavailable during daylight hours, but energy isconsumed around the clock. In the absence ofinexpensive storage, nighttime and cloud cov-er limit the potential of terrestrial solar tech-nologies (with the exception of ocean thermalenergy conversion) to supply the amounts ofenergy required for use in homes, businesses,and industries. By placing the solar collectorsin space where sunlight is intense and con-stant, and then “beaming” energy to Earth, thesolar power satellite (SPS) seeks to assure abaseload supply of electricity for terrestrialconsumers.

Several radically different versions of SPShave been proposed, most of which will be de-scribed and analyzed in this report. In the mostextensively studied version, a large satellitewould be placed in the geosynchronous orbitso that it remains directly above a fixed pointon the Earth’s Equator. Solar photovoltaicpanels aboard the satellite would collect theSun’s radiant energy and convert it to elec-tricity. Devices would then convert the elec-tricity to microwave radiation and transmit itto Earth where it would be collected, recon-verted to electricity, and delivered to the elec-tric power grid. An alternative concept envi-sions using large orbiting reflectors to reflectsolar radiation to the ground, creating im-mense solar farms where sunlight would beavailable around the clock. Laser beams havealso been proposed for the energy transmissionmedium. These concepts may have significant-ly different economic prospects, as well as dif-

ferent degrees of technical feasibility. In addi-tion, they would affect the environment andpolitical and financial institutions in differentways.

The first serious discussion of the SPS con-cept appeared in 1968. ’ 2 During the next fewyears several companies conducted prelimi-nary analyses with some support from the Ad-vanced Programs Off ice of the National Aero-nautics and Space Administration (NASA).3

In May 1973, the Subcommittee on SpaceScience and Applications of the House Scienceand Astronautics Committee heId the first con-gressional hearings on the concept.4 Followingthose hearings, NASA began a series of experi-ments in microwave transmission of power atthe Jet Propulsion Laboratory. In 1975, NASAcreated an SPS study office at the JohnsonSpace Center that performed several addi-tional systems studies. A number of paperswere published, s culminating in an extensivereport that established most of the basis forthe Department of Energy’s (DOE) referencesystem design. 6

In the beginning it had been assumed thatNASA would be the Federal agency with primeresponsibility for satellite power stations.However, the Solar Energy Act of 1974 clearlyplaced the responsibility for all solar energyR&D aimed at terrestrial use under the jurisdic-

1 P E Claser, “The Future of Power From the Sun, ” lntersocie-

ty Energy Conversion Engineering Conference (l ECEC), IEEE pub-lication 68C-21 -Energy, 1968, pp. 98-103,

2P E Glaser, “Power From the Sun: Its Future,” Science 162,NOV 22, 1968, pp. 857-886,

‘P E Claser, O. E, Maynard, J. Mockovciak, and E, L, Ralph,“Feasibility Study of a Satellite Solar Power Station,” Arthur D.Little Inc , NASA CR-2357 (contract No. NAS 3-16804), February1974.

“’Power From the Sun via Satellite, ” hearings before theSubcommittee on Space Science and Applications and Subcom-mittee on Energy of the Committee on Science and Astronautics,U S House of Representatives, May 7, 22, 24,1973.

5Wlll lam J. Richard, “Geosynchronous Satellite Solar Power,”ch, 8 of So/ar Energy for Earth: An A /AA Assessment, H. J. Kill ian,G L Dugger, and J. Grey (eds.), AlAA, Apr. 21, 1975, pp. 59-71.(Also see abridged version in Astronautics and Aeronautics,November 1975, pp. 46-52.)

“’ln(tlal Technical, Environmental, and Economic Evaluationof space solar Power Concepts, ” report No. j SC-11568, VOIS. Iand II, NASA, Aug. 31, 1976.

17


tion of the Energy Research and DevelopmentAdministration (ERDA). ERDA set up a TaskGroup on Satellite Power Stations, and in No-vember 1976 recommended two options forconducting a joint ERDA/NASA 3-year SPSconcept development and evaluation pro-gram, one costing $12 million and one $19 mil-l ion. ’ ERDA elected to pursue a mediancourse, and proposed a 3-year, $15.5 million ef-fort which began in fiscal year 1977, the SPSConcept Development and Evaluation Pro-gram.

ERDA’s efforts were given impetus by twocongressional hearings, one held in January1976 by the Subcommittee on Aerospace Tech-nology and National Needs of the SenateAeronautical and Space Sciences Committee8

and one held in February 1976 by two subcom-mittees of the House Committee on Scienceand Technology.9

When DOE was created in 1977, it estab-lished a special Satellite Power System projectoffice in the Office of Energy Research to com-plete the Concept Development and Evalua-tion Program. Its final report was released onDecember 1, 1980.’0

The SPS research, development, and demon-stration bill, ’ which was introduced in theHouse of Representatives on January 30, 1978,reflected a desire by a number of Members ofCongress to accelerate the evaluation of SPSand to introduce a more ambitious technologyverification effort. It was reported out by theScience and Technology Committee after

7Robert A. Summers (chairman), “Final Report of the ERDATask Croup on Satellite Power Station,” report No. ERDA-76/l 48,November 1976.

“’Solar Power for Satellites, ” hearings before the Subcommit-tee on Aerospace Technology and National Needs of the Com-mittee on Aeronautical and Space Sciences, U S. Senate, J an, 19,21,1976, GPO stock No, 66-608-0, 1976

“’Solar Satellite Power System Concepts,” hearings before theSubcommittee on Space Science and Applications and the Sub-committee on Energy Research, Development, and Demonstra-tion of the Committee on Science and Technology, U.S. House ofRepresentatives, Feb. 20,1976 (No 67)

‘“Satellite Power Systems Concept Development and Evalua-tion Program, “Program Assessment Report Statement of Find-ings, ” DOE/E R-0085, November 1980,

“Ronnie Flippo, “Solar Power Satellite Research, Develop-ment, and Demonstration Program Act of 1978, ” H .R 10601, J an.30,1978.

another round of hearings, ’2 and eventuallypassed by the full House. No Senate bill was in-troduced. A similar bill,13 reintroduced in 1979,was passed by the House on November 16,1979, but again died in the Senate.

The DOE/NASA Concept Development andEvaluation Program 14was established to iden-tify and evaluate the possible technical, en-vironmental, social, institutional, and econom-ic aspects of the SPS concept. It has generateda broad range of reports that reflect this in-tent. 5 In order to have a fixed technical basisfor the study, DOE and NASA developed twoversions of a “reference” satellite power sta-tion system, based on extensive studies under-taken by two NASA contractors. 16 17 Althoughthe reference system represented the bestchoice based on the information available atthe time, it was not intended to be the lastword in systems definition; the multitude ofother options that have been proposed sincealso need to be evaluated before ultimatelysettling on a “baseline” system design.

OTA was requested by the House Commit-tee on Science and Technology to pursue anindependent study to “assess the potential ofthe SPS system as an alternative source ofenergy.’” 8 Hence, this study primarily ad-dresses the benefits and drawbacks of SPS asan energy system. It also identifies the key

“’Solar Power Satellite, ” hearings before the Subcommitteeon Space Science and Applications and the Subcommittee onAdvanced Energy Technologies and Energy Conservation Re-search, Development, and Demonstration of the Committee onSc[ence and Technology, U.S. House of Representatives, Apr12-14, 1978 (No, 68), CPO stock No. 28-155-0, 1978,

‘ ‘Ronnie Flippo, “Solar Power Satellite Research, Develop-ment, and Evaluation Program Act of 1979, ” H R. 2335, Feb. 22,1979

“’’Satellite Power System Concept Development and Evalua-tion Program Reference System Report,” U S. Department ofEnergy report No DOE/E R-0023r October 1978.

‘sSee the extensive set of references in note 10“C Woodcock, “Solar Power Satellite System Definition

Study, ” Boeing Aerospace Co., Johnson Space Center (contractNo NAS 9-151 96), pt. 1, report No. DI 80-22876, December 1977,pt 111, report No D18024071, March 1978

“C Hanley, “Satellite Power System (SPS) Concept Defini-tion, ” Rockwell International Corp., Marshall Space Flight Cen-ter, (contract No. NAS 8-32475), report No. SD78-AP-0023, April1978

“Letter of request to OTA from the House Committee onSC Ience and Technology, Aug 8,1978

Ch. 2—Introduction ● 7 9

uncertainties of the various SPS concepts andrelated needs for R&D.

Although SPS would be an energy system itis unique in being a major space system aswell. It would therefore require a large newcommitment to the development of spacetechnology. Hence, this report also addressesthe relationship of an SPS program to otherspace programs.

OTA has divided the assessment into fourmajor areas: 1) SPS technical alternatives andeconomics, 2) issues arising in the public de-bate, 3) institutional and international ques-tions, and 4) the programmatic context, i.e.,the place of SPS within our national energyand space programs. A number of workingpapers were written to provide data for theseareas. OTA also convened three workshops torefine and amplify the data presented in sev-eral of the working papers: 1) SPS TechnicalOptions and Costs, 2) SPS Public OpinionIssues, and 3) The Energy Context of SPS.

●

●

• SPS technical options and costs. The ma-jor task of the workshop was to assess theDOE/NASA reference system from a tech-nical perspective and to study alterna-tives. It discussed the key uncertainties ofeach major system or subsystem that hasbeen suggested in SPS literature andchose four generic systems for furtherevaluation in later workshops: 1) the ref-erence system, 2) a solid-state variant ofthe reference system, 3) a laser system,and 4) a mirror system.SPS public opinion issues. Participantswith experience in analyzing and respond-ing to a variety of public interests andconcerns met to identify the major issuesthat could affect the public perceptionsof SPS. The workshop was not an exercisein public participation. Rather, it sought a

range of viewpoints from participantswho have a sense of the issues, the politi-cal players, and public attitudes involved.The energy context of SPS. SPS will suc-ceed or fail in competition with other en-ergy supply options and in the context ofnational and global demand for electric-ity. This workshop developed criteria forchoosing between technologies and com-pared the major future alternative renew-able or inexhaustible sources of baseloadelectrical power. Participants discussedthe many factors that wouId affect futureelectricity demand and compared breederreactors, fusion, terrestrial solar thermal,and solar photovoltaic baseload options.They also discussed the potential role ofdispersed photovoltaic systems in meetingpart of the Nation’s electrical needs.

Because the SPS concept would use a com-plex future technology about which there aremany uncertainties, this assessment is funda-mentalIy different from an assessment of cur-rent technology. While it is thought to be tech-nically feasible, many of the details are un-certain; economic projections or possible en-vironmental effects based on them are also un-certain, sometimes by more than an order ofmagnitude. Hence at this point OTA must besatisfied with identifying the key uncertaintiesof SPS and, where applicable, suggesting alter-nate strategies for resolving them. The studyalso analyzes the major institutional and inter-national issues that accompany decisionsabout SPS, i.e., how it may affect nationalsecurity, the international energy market, theutilities industry, and how an SPS projectmight be financed and managed. Although adefinitive treatment of any of these issuesmust wait for the future, this report attemptsto lay the foundation for further considerationof SPS.

Chapter 3

ISSUES AND FINDINGS

ContentsPage

Technical Options .. .... . . . . . . . , . . . 23Microwave Transmission . . . . . . . . . . . . 23Laser Transmission . . . . . . . . . . . . . . . . . 24Reflected Sunlight . . . . . . . . . . . . . . . . . 27SPS Scale . . . . . . . . . . . . . . . . . . . . . . . . 28Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

SPS and the Energy Future . . . . . . . . . . . . . 30SPS ls Not Likely To Be Commercially

Available Before 2005-15 . . . . . . . . . . 30SPS Would Not Reduce U.S.

Dependence on lmported Oil . . . . . . . 32Potential Scale of Electrical Power. ,... 32Electricity Demand Would Affect the

Need for Solar Power Satellites. . . . . . 32Comparison to Other Renewable

Options . . . . . . . . . . . . . . . . . . . . . . . . 33

Utilities. . . . . . . . . . . . . . . . . . . . . . . . . . . . 33Nontechnical Considerations . . . . . . . . . 35Ownership and Finance . . . . . . . . . . . . . 36

International implications . . . . . . . . . . . . . 37

National Security Implications. . . . . . . . . . 38

Public Issues... . . . . . . . . . . . . . . . . . . . . . 41

Environment and Health. . . . . . . . . . . . . . . 41

Electromagnetic Compatibility . . . . . . . . . 48The Public . . . . . . . . . . . . . . . . . . . . . . . . 48Space Communications . . . . . . . . . . . . . 48

Terrestrial Communications andElectronic Systems . . . . . . . . . . .

Effect on Terrestrial Astronomyand Aeronomy . . . . . . . . . . . . . . . .

Space Program . . . . . . . . . . . . . . . . . . . .

LIST OF TABLES

TableNo.l, Characterization of Four Alternative SPS

Systems . . . . . . . . . . . . . . . . . . . . . . . . . . .

Page

50

50

52

Page

312. Major lssues Arising in SPS Debate . . . . . . . . 423. Summary of SPS Environrnental Impacts. . . . 434. SPS Systerns Land Use .

LIST OF F

Figure No.

12

34

. . . . . . . . . . . . . . . . 47

GURES

Page

The Reference System . . . . . . . . . . . . . . . . . . 24The Solid-State Variant of the ReferenceSystem . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25The Laser Concept . . . . . . . . . . . . . . . . . . . . 26The Mirror Concept (SOLARES) . . . . . . . . . . . 28

5. Reference System Costs . . . . . . . . . . . . . . . . . 296. The Number of Geosynchronous

Satellites as a Function of Time . . . . . . . . . . . 497. The SPS Brightness Profile . . . . . . . . . . . . . . . 51

TECHNICAL

What technical options might be availablefor SPS?*

A number of technical options for the solarpower satellite (SPS) have been proposed. Be-cause SPS is a developing technology, the spe-cific design parameters of each of these ap-proaches are evolving rapidly as research con-tinues. Hence no single option is completelydefined, nor are there detailed systems studiesof any designs other than the National Aero-nautics and Space Administration/Departmentof Energy (NASA/DOE) “reference system”that uses microwaves for transmitting energyfrom space to Earth. The reference design isthe basis for the NASA/DOE environmental, so-cietal, and comparative assessments. The twoother major SPS variants depend on laser trans-mission of power from space and on reflectedsunlight.

Microwave Transmission

The Reference System Design

The reference system satellite conceptualdesign consists of a 55 square kilometer(km2)** flat array of photovoltaic solar cellslocated in the geostationary orbit 35,800 kmabove the Earth’s Equator (fig. 1). The cellsconvert solar energy into direct-current (de)electricity that is conducted to a 1-km diame-ter microwave transmitting antenna mountedat one end of the photovoltaic array. Micro-wave transmitting tubes (klystrons) convert theelectrical current to radio-frequency power at2.45 gigaHertz (GHZ), and transmit it to Earth.A ground antenna receives the electromag-netic radiation and rectifies it back to directcurrent; hence its designation “rectenna.” Thedirect-current (de) power can be inverted toalternating-current (ac) and “stepped up” to

*See ch. 5.**Equivalent to about 13,600 acres

OPTIONS

high voltage. It would then be either rectifiedto dc and delivered directly to a dc transmis-sion network in the terrestrial utility grid orused as conventional ac power. The rectennacovers a ground area of 102 km2 and would re-quire an “exclusion area” around it of an addi-tional 72 km2 to protect against exposure tolow-level microwaves. The beam density at thecenter of the rectenna is 23 milliwatts persquare centimeter (mW/cm2). The beam isshaped in such a way that at the edge of the ex-clusion area it reaches 0.1 mW/cm2.

For the given set of design assumptions forthe reference system, i.e., beam density, taper,and frequency, the maximum power per trans-mitter-receiver combination would be 5,000MW. Except for a small seasonal variation inoutput due to the variation of the Sun’s dis-tance from the Earth, and short periods ofshadowing by the Earth near the time of thespring and fall equinoxes, each reference sys-tem satellite could be expected to deliver themaximum amount of power to the grid approx-imately 90 percent of the time. This powerlevel was selected by NASA/DOE for the ref-erence system in the belief that it would pro-vide energy at the lowest cost. 1 n subsequentdiscussions it is used to consider the impact ofthe reference system design on utilities andtheir systems; however, the power level couldbe set at any value permitted by the designconstraints.

The reference system, which was developedto provide a base for further studies and is nowseveral years old, is far from an optimummicrowave system and could be substantiallyimproved. In addition, alternative conceptsthat depend on laser transmission or passivereflection of sunlight each offer certainspecific benefits over the microwave designs.Because none of these alternatives are as welldefined as the reference system, they arediscussed here in more general terms.

23


Figure 1 .—The Reference System

Arraystructure

Solar cell array

Transmitting antenna subarray

DC-RFpower amps

Antenna waveguides

SOURCE: C. C. Kraft, “The Solar Power Satellite Concept,” NASA publication No. JSCp14898, July 1979.

The Solid-State Variant

Using solid-state devices that convert elec-tricity from the satellite’s solar array directlyto microwave power would be a possible alter-native to the reference system’s klystrons.Such devices might have a longer working life-time and require less mass in orbit; when cou-pled with photovoltaic cells in a “sandwich”design, they would also allow for a much largertransmitting antenna (the entire surface areaof the solar cells would, in effect, be the anten-na), smaller earthside antennas, and lowerpower delivered to Earth per satellite (i.e.,about 1,000 MW per rectenna). In combina-tion, these effects would make it possible toposition rectennas closer to the cities, whichwould be the major users of SPS generatedpower, than would the reference systemdesign.

Solid-state devices are now in the very earlystages of being evaluated for SPS application.It is still unclear whether they would be able toreach the efficiency and cost goals that wouldbe necessary for SPS.

Laser Transmission

Lasers constitute an obvious alternative tomicrowaves for the transmission of power overlong distances. Compared with microwaves,lasers have a much smaller beam diameter;since the aperture area of both transmittingand receiving antennas decreases as the squareof the wavelength, light from an infraredwavelength laser can be transmitted and re-ceived by apertures over 100 times smaller indiameter than a microwave beam. This re-duces the size and mass of the space segmentand the area of the ground segment. Perhapseven more important, the great reduction inaperture area permits consideration of fun-damentally different systems. For example:

● It would become possible to use low Sun-synchronous rather than high geostation-ary orbits for the massive space powerconversion subsystem (a Sun-synchronousorbit is a near-polar low Earth orbit thatkeeps the satellite in full sunlight all thetime while the Earth rotates beneath it).The primary laser would then beam its

Ch.3— Issues and Findings ● 25

Figure 2.—The Solid-State Variation of the Reference System

●

Reflected sunlight

Solid-stateamplifierpanel

cell

Solar array/microwave antennasandwich panels

SOURCE: G. M. Hanley, et al., “Satellite Power Systems (SPS) Concept Definition Study First Performance report No. SS D 79-0163, NASA MSFCcontract No. NAS8-32475, Oct. 10, 1979.

power up to low-mass laser mirror relaysin geostationary orbit for reflection downto the Earth receiver. This arrangement,while complex, would considerably re-duce the cost of transportation, since thebulk of the system would be in low Earthorbit rather than in geostationary orbit. Italso could be built with smalIer trans-portation vehicles than the reference sys-tem’s planned heavy lift launch vehicle(HLLV).A laser system might be able to operateefficiently and economically on a smallerscale (100 to 1,000 MW). Thus, it wouldoffer the flexibility of power demandmatching on the ground, making possiblehigher degrees of redundancy and asmaller and therefore less costly systemdemonstration project.

● The potentially small size of the receivingstation would make it possible to employmultiple locations close to the points ofuse, thereby simplifying the entire grounddistribution and transmission system.

● Laser power transmission would avoid theproblem of microwave biological effectsand would reduce overall interferencewith other users of the electromagneticspectrum.

A laser SPS would suffer from three impor-tant disadvantages:

● Absorption of laser radiation. Infrared r a -diation is subject to severe degradation orabsorption by clouds. A baseload system,unlike the microwave option, would re-quire considerable storage capacity tomake up for interruptions. Multiple re-

83-316 0 - 81 - 3


Figure 3.—The Laser Concept (One Possible Version)

1Solar power satellite Relay unit(s)

Ground site

Synchronous r e l a y s

Occultedpowersatellites

Sun

Ch. 3—Issues and Findings ● 27

●

●

ceivers at different locations to achievesome redundancy are also possible, butexpensive (seeUtilities, ch. 9).

Efficiency. Current high-power, continu-ous-wave lasers are only capable of verylow overall power conversion efficiencies(less than 25 percent). Converting thebeam back into electricity is also ineffi-cient, though progress in this area hasbeen rapid. The relatively undevelopedstatus of laser generation and conversionmeans that considerable basic and ap-plied research would be needed to deter-mine the feasibility of a laser SPS.

Health and safety hazard. The beam inten-sity would be great enough to constitute ahealth and safety hazard. Preventivemeasures could include a tall perimeterwall, and/or a warning and defocusingsystem.

Several types of continuous wave lasers cur-rently exist. Of these, the most highly devel-oped and most appropriate laser for SPS wouldbe the electric discharge laser (EDL). At pres-ent, EDL models have achieved only modestpower levels and relatively low efficiencieswhen operated in a continuous mode.

Another future option that has been consid-ered is the solar-pumped laser. In this device,concentrated sunlight is used directly as theexciting agent for the laser gases. Although asolar-pumped laser has been built and oper-ated successfully at NASA Langley, it would re-quire considerable basic research, develop-ment, and testing before it could be a realisticprospect for SPS.

Free electron lasers (FELs) offer anotherpossible means of transmitting power fromspace. These new devices are powered by abeam of high-energy electrons which oscillatein a magnetic field in such a way that theyradiate energy in a single direction. Althoughthe FEL has been demonstrated experimental-Iy, it is too early to predict whether it would

reach the efficiencies and reliability necessaryfor an SPS.

Reflected Sunlight

Instead of placing the solar energysion system in orbit, large orbitingcould be used to reflect sunlight tobased solar conversion systems. Thus,tern’s space segment could be much

conver-mirrors

ground-the sys-simpler

and therefore cheaper and more reliable.

One such system would consist of a numberof roughly circular plane mirrors in variousnonintersecting Earth orbits, each of whichdirects sunlight to the collectors of a numberof ground-based solar-electric powerplants asit passes over them. Conversion from sunlightto electricity would occur on the surface of theEarth.

In one approach, (the so-called “SOLARESbaseline” concept) about 916 mirrors, each 50k m2 in area, would be required for a globalpower system projected to produce a total of810 gigawatts (GW) (more than three times cur-rent U S. production) from six individual sites.This is not necessarily the optimum SOLARESsystem. It was selected here to demonstratethe magnitude of power that might beachieved with such a system. However, a num-ber of different mirror sizes, orbits, and groundstation sizes are possible. A more feasible op-tion would be a lower orbit system (2,100 km)to supply 10 to 13 GW per terrestrial site. Oneof the principal features of the SOLARES con-cept is that it could be used for either solar-thermal or solar photovoltaic terrestrial plants.The fact that energy conversion would takeplace on the surface of the Earth keeps themass in orbit small, thereby reducing trans-portation costs.

However, a major disadvantage of such amirror system would be that the entire systemwould require an extremely large contiguousland area for the terrestrial segment (see table4, p. 47). As with the laser designs, transmissionthrough the atmosphere would be subject to

28 • Solar Power Satellites

Figure 4.–The Mirror Concept (SOLARES)

reduction

Photo credit National Aeronautics and Space Administration

SOURCE: K. W. Billman, “Space Orbiting Light Augmentation Reflector Energy System: A Look at Alternative Systems,”SPS Program Review, June 1979.

or elimination by cloud cover. It trical power to the United States or to otherwould also illuminate much of the night sky(see issue on electromagnetic interference) asseen by observers within a 150-km radius of thegroundsite center.

SPS Scale

As presently conceived, the reference sys-tem is a large-scale project that has the poten-tial of delivering hundreds of gigawatts of elec-

countries. However, its very scale is seen bymany as a serious drawback to deployment.The utilities here and abroad would find ithard to accommodate power in 5,000 MWblocks (see Utilities, ch. 9), and the spacetransportation system needed to build andmaintain such a massive system would be veryexpensive. Thus, it is of considerable interestto investigate ways in which the scale of thevarious components, and of the system itself,couId be reduced to a more manageable size.


The laser system would offer the potentialfor the most substantial reductions, both inoverall system size and in the size of the firstdemonstration project. This reduction in scalemight also bring with it a concomitant reduc-tion of costs. There are also a number of possi-ble ways in which to reduce the physical scaleof portions of the microwave system. How-ever, economies of scale tend to drive micro-wave systems to sizes of 1,000 MW output ormore.

SPS would require a massive industrial infra-structure for space transportation and con-struction and for related terrestrial construc-tion, comparable in scale to that developed forexisting ground-based coal and nuclear sys-tems.

●

●

Space transportation. The reference sys-tem assumes the construction and use of alarge third-generation, shuttle-type trans-portation system. Construction of a singlereference system satellite (silicon photo-voltaics) would require approximately 190flights of an HLLV. However, launch vehi-cles somewhat larger than the currentshuttle, but smaller than the HLLV, are ca-pable of operating with less load per flightbut with many more flights and might bemore economical. I n addition, an inter-mediate size vehicle would be more ap-propriate for other uses in space. No othercurrently planned space project envisionsusing vehicles the size of an HLLV.Space construction. SPS would requireconstruction bases in low Earth orbit and,for some designs, at geostationary orbit. Itmight be possible to achieve substantialcost reductions by constructing the satel-lites in low Earth orbit and transportingthem to geostationary orbit, rather thanby constructing them in geostationary or-bit.

costs

Although the costs of many SPS componentshave been estimated by a number of differentagencies, it is not yet possible to establishthem with any reasonable level of confidence.

The most detailed cost estimates have beenmade by NASA for the reference system (fig. 5):$102.4 billion to achieve the first completereference system satellite, and $11.3 billion toconstruct each satellite thereafter.

These estimates included the costs of the en-tire transportation system, the costs of estab-lishing the launch sites and construction facil-ities in low-Earth and geosynchronous orbits,as well as all of the component development

Figure 5.—Reference System Costs a

(dollars in billions)

aNASA estimates— 1977 dollars.

SOURCE: National Aeronautics and Space Administration


costs. However, they do not include interest onthe invested capital or the potential use of SPSfacilities for other space or terrestrial projects.According to one possible development sce-nario generated by NASA (see fig. 24, p. 93), in-cluding interest of 10 percent per year morethan doubles the development cost of SPS.

By using a smaller capacity transportationsystem (assuming more flights per satellite),and apportioning the development costs ofgeneric space technology among all the spaceprograms that benefit from it, it might well bepossible to deploy a single reference satellitefor $40 billion to $50 billion, or roughly one-half of the above estimate.

Other systems might cost more or less thanthe reference system, depending on the stateof development of the alternative technol-ogies (see table 1). For example, since laserswould need considerable development beforethey would be suitable for use in a laser-powered SPS, they would be likely to be moreexpensive to develop than the microwave

SPS AND THE

How could SPS flt into the U.S. energy future(2000-30)?*

SPS will ultimately be accepted or rejectedin the full context of future electrical demandand supply technologies. It would competewith other renewable or inexhaustible energysources such as hydro, wind, terrestrial solar,ocean thermal energy conversion, fusion, fis-sion breeder, and geothermal. Their tech-nologies are all quite different; some serve ademand for baseload, some for peaking orintermediate needs. Together, they would con-stitute a mix of technologies designed to sup-ply the full range of electrical needs for theUnited States. SPS must be considered in lightof its potential contribution to this mix, as wellas of future electrical demand.

*See ch. 6, Energy section.

transmitter of the reference system; however,some of the development cost could con-ceivably be borne by other laser applications,e.g., directed energy weapons or inertial fu-sion. The cost of a laser demonstration satel-lite might well be less than the reference sys-tem demonstrator. Because of the relativelylow mass and ease of construction and opera-tion of a SOLARES system, it may prove to bemuch more attractive than other alternatives.Cost estimates suggest that if the cost of ter-restrial photovoltaics can reach the goals im-plied by reference system estimates, the costsof a total SOLARES system would be less thanthe reference system. More exact costs for theSPS await further information on the details ofthe preferred system. Whatever system mightbe chosen, it is clear that the startup costswould be in the tens of billions. How much ofthis cost would have to be borne by the U.S.taxpayer depends on the breadth and depth ofindustrial and international interest in the de-velopment of SPS (see ch. 7).

ENERGY FUTURE

SPS Is Not Likely To Be CommerciallyAvailable Before 2005-15

Experience with other new electric generat-ing technologies indicates that new technol-ogies take from 30 to 45 years to become asignificant source of electrical capacity in theutility grid. SPS is unlikely to constitute a ma-jor exception to this rule of thumb. If a deci-sion to develop SPS were made, some 15 to 25years of development, engineering, and dem-onstration would be needed to reach a com-mercial SPS. However, because of the manyuncertainties surrounding SPS, it is not yetpossible to make a development decision. If,after considerable further research a decisionis made in the next decade to proceed withSPS, then it could be commercially available inthe period between 2005 and 2015. Severalyears of operational testing beyond that would

Table 1.—Characterization of Four Alternative SPS Systems

Information matrix Reference design Solid state Laser system SOLARES (“baseline”)a

costsR&D $400 million More R&D needed than reference system More R&D needed than reference system

$102 billion DDT&E (one sateilite) b

Relatively simple technical lower cost

Demonstration Smaller, demonstration with shuttle?

Construction$44 billion, demonstration with shuttle?

$11,5 billion/satellite Unit cost lower, smaller rectenna $3 billion satellite (0,5 GW) $1,300 billion for 810 GW total systemOperation $200 million/yr-5GW Greater reliability, long lifetime 25 million/yr-satellite (0.5GW) Higher ground conversion costDollars/kW $2,900 -19,000/kWc $1 ,800 -3,000/kW (probably low) $6,000/kW probably low) $1,500/kW (probably low)

ScaleSatellite sizeNumber of satellitesPower/satelliteMassLand use rectenna site

km 2 1,000 MW

55 km2 18 km2

60 (300 GW total) Not projected5,000 MW 1,500 MW5 X104 tonnes/satellite, O 1 kW/kg Less mass than reference/O 1 kW/kg174 km2 (including buffer) 50 km2

x 60=10,440 km2

35 33

5 km2 50 km2

Not projected 916 (810 GW total)500 MW 135,000 MWLess mass than reference/O .05 kW/kg 2 x 105tonnes mirror system 2 kW/kg0.6 km2 1,000 km2

1,2 7.4

Energy Electricity ElectricityFairly centralized Less centralized

23 mW/cm2 Gaussian distribution Unknown

Electricity, onsite generation. Electricity, lightLess centralized Highly centralizedUnknown (10 mW/cm2 at edge) 1.15 kW/m2 (1 Sun)

AtmosphereTransmission Ionosphere heating might affect telecommunications Tropospheric heating might modify weather over smaller area; problems with clouds?Effluents Possible effects include alteration of magnetosphere (AR+); increased water content; LEO orbit, smaller size; smaller launch vehicles

formation of noctilucent clouds; ionosphere depletion

Electromagneticinterference RFI from direct coupling, spurious noise, and harmonics: impacts on communications,

satellites etc from 245 GHz Problem for radio astronomers (GEO obscures portion ofsky always) optical reflections from satellites and LEO stations WiII change the night sky

Bioeffects Microwave bioeffects midbeam could cause thermal heating unknown effects of long-term exposure to low-level microwaves, Ecosystem alteration? Birds avoid/attractedto beam?

National securityweapons potential GEO gives a good vantage point over hemisphere

–Provides a lot of power in space platform for surveillance, jamming–

–Requires developement of Iarge space fleet with/militarv potential–

If visible light IS used there may be problems Problem for optical astronomy, optical reflec-for optical astronomy; if Infrared IS used may tions and interference from beam; changeIncrease airglow optical reflection from LEO night sky in vicin of sitessatellite

Direct beam ocular and skin damage ocular Psychological and physiological effects of 24-damage from reflections? Other effects? Birds hour illumination not known Possible ocularflying through WiII burn up? If visible will hazard if viewed with binoculars? Ecosystembirds avoid? Ecosystem alterations? alteration

Direct weapon: as ABM, antisatellite, aimed at Indirect: night illumination psychological–terrestrial targets possible weather modification

Indirect: power killersatellite, planes space platformLaser defend self, best, LEO more accessible

Vulnerability Satellites may need self defense system to protect against attackSize and distance strong defenses–

Less ground sites; a lot of mirrors-redun-dancy; individual mirrors fragile; ground sitesstil l produce power in absence of spacesystem

International Will require radio frequency allocation and orbit assignment LEO more accessible to U.S.S.R. and high-lahtude countries, smaller parcels of energy makeSmaller parcels of energy make system more system more fiexibleflexible

Meet environmental and health standards?

asmaller saLAREs systems, e g 10 GW/sde would be possible and probably more desirableb$loz bllllon–NASA estimate–mcludes Investment costscEst(mates by Argonne National Laboratory, Office of Technology Assessment, U S Con9ress

SOURCE Offlceof Technology Assessment


be needed before utilities developed enoughconfidence in SPS to invest in it for their use(see ch. 9).

SPS Would Not Reduce U.S.Dependence on Imported Oil

Currently the biggest energy problem fac-ing the Nation is dependence on unreliablesources for imported oil. This dependence willpersist for the next two decades, since ourdomestic supplies will continue to decline. Wenow produce about 10 million barrels per day(bbl/d) of petroleum liquids and this will likelyfall to 4 million to 7 million bbl/d by 2000. Thesupply of abundant domestic energy resourcessuch as coal, solar, uranium, and natural gascan increase but not enough to offset the de-cline in oil. Over this period our best opportu-nity for reducing dependence on imports willbe conservation, which has the potential ofcutting current dependence by more than 50percent. However, the real problem will be thesubstantial reduction in availability of worldoil for export to the United States. The totalamount of oil available is not likely to exceedthe current level of 52 million bbl/d and maybe as much as 15 percent below this level. Fur-ther, overall world demand will likely be higherbecause of increased needs by less developedcountries (LDCS), including oil producing coun-tries. As a result, the United States will find itnecessary to reduce imported oil dependenceconsiderably by 2000. This reduction will beeven more marked past 2000, when we can ex-pect synthetic fuels from all sources to make asubstantial contribution. Since the SPS will notbe able to make a significant contribution un-til well past 2000, it cannot be expected to sub-stitute for foreign oil. However, the satellitecould eventually begin to substitute for coal-fired powerplants since coal, too, is a finitefuel, and regardless of the outcome of the CO,controversy, use of it for electric productionwill eventually (though probably not for thenext 100 years) be reduced and reserved fornonenergy needs, i.e., for plastics, syntheticfiber, etc.

Potential Scale of Electrical Power

The reference system is designed to deliver 5GW (5,000 MW) of power to each rectenna. If a60-satellite U.S. fleet were completed, the SPScouId deliver a total of 300 GW, an amountnearly one-half the current total U.S. generat-ing capacity. Converted to energy at a capac-ity factor of 90 percent, a 60-satellite systemwould produce about 8 Qe/yr, more electricalenergy than we currently consume from allsupply sources (7.5 Qe). An international fleetof satelIites could achieve a much greater ca-pacity than this by placing more satellites ingeostationary orbit. A SOLARES-type systemcould achieve an even greater generatingcapacity on an international scale.

other proposals, such as the laser systemand variants of the microwave system might beeconomical in somewhat smaller unit sizes(500 to 1,000 MW). Precisely how much totalenergy they might supply is less clear, how-ever. For example, a laser system supplyingpower in 1,000 MW units would need 300 suchsatellites and ground receivers in order toequal the capacity of a 60-satellite referencesystem.

Electricity Demand Would Affect theNeed for Solar Power Satellites

The level of electricity demand in the UnitedStates and the world will greatly affect thetime that new centralized electric generatingtechnologies, such as SPS, might be needed.The demand for electricity could vary con-siderably over the next several decades. Forthe United States, current forecasts show arange in possible electrical demand from lessthan today’s level of 7.5 Qe end-use to morethan 30 Qe by 2030. The demand level will be amajor determinant of the rate at which newelectric generating technologies need to beintroduced. At the lowest levels, all of ourbaseload capacity could easily be supplied byhydro and coal or nuclear for well into the 21st


century provided C02 buildup does not pre-clude increased coal use. At high demandlevels, however, it is unlikely that any onetechnology could provide all the needed base-Ioad capacity and several possibilities wouldbe needed. In this case, development of SPSmay be attractive, even assuming successfuldevelopment of fusion or breeder reactors.

An emerging factor that will strongly affectelectricity demand is the success in developingdemand technologies that use electricity veryefficiently. It is likely over the next severaldecades that the price of electricity will comeclose enough to other forms of energy (syn-thetic fuels, direct solar, etc.) that the relativeefficiencies of the end-use equipment will de-termine which energy form is the cheapest.Therefore, electricity demand could grow con-siderably if such things as very efficient spaceand water heat pumps, electrochemical indus-trial processes, and high-capacity storage bat-teries are developed. If these are not forth-coming and the conventional ways of using en-ergy–direct combustion of liquid and gaseousfuels–continue to be most prevalent, thenelectricity demand in the United States wilI notincrease rapidly if at al 1. Therefore, the even-tual need for solar power satellites and othercentral electric technologies would be deter-mined as much by the development of effi-cient electric demand technologies as by itseconomics relative to other electric energytechnologies.

Comparison to OtherRenewable Options

Ultimately the United States and the worldwill choose or reject SPS as an energy supplyoption on the basis of comparative costs aswell as environmental and social impacts. OTAhas generated a number of criteria for thechoice of energy technologies and comparedSPS with other renewable or inexhaustible op-tions (fusion, nuclear breeder, terrestrial solarthermal, and solar photovoltaic) on the basisof those criteria (see table 16, p. 11 6). Whatemerges from such comparisons is that if theresearch, development, demonstration, andtesting (RDD&T) costs and the estimated costper installed kilowatt can be lowered sig-nificantly, SPS could compete with the alter-natives on an economic basis. SOLARES, forinstance, might already be economical com-pared to conventional nuclear. SPS technicaluncertainties are much higher than for thebreeder, but lower than for fusion. Social costsare extremely difficult to determine, but ifresearch demonstrated the microwave andIonizing radiation hazards to be low, SPS couIdsubstitute low-risk environmental hazards forthe high risks of coal or nuclear as well as con-tribute to an expanded space program. ItwouId take longer to commercialize than ter-restrial solar or breeder, but less than fusion. I ncompetition with other technologies, overalldemand for electricity, and the timing of thecommercial introduction of SPS vis-a-vis otheroptions wilI be crucial.

UTILITIES

Would SPS be acceptable to the utilities?* and available as their designers suggest they

The major factors that would affect the util-ities’ decision about SPS technology are cost,reliability, unfamiliarity with space systems,and institutional questions. Only demonstra-tion, and successful experience with an opera-tional SPS over several years, would assure theutilities that it is a viable technology for theiruse. If the microwave systems were as reliable

*See ch 9, The Irnpl;cat;ons for the Utility /ndustry section

could be (90 percent or more), the utilitieswould welcome them for baseload generation,assuming their size and costs were also appro-priate. The laser system might be of interest tothe utilities if it could be used to repower exist-ing thermal facilities. The suggested unit sizeof the laser system (500 to 1,000 MW) would fitwelI into the present size mix of terrestrialpowerplants. A mirror system with its highlycentralized, energy producing facility (10 to


100 GW) would be too large for the presentsize mix, but would offer the potential forsome flexibility in energy production. Directelectricity and hydrogen generation are bothpossible in a SOLARES-type energy park. How-ever, because the SPS would be an integralpart of the utility grid, it would impose certainconstraints on grid dispatch management. Thephysical requirements of the rest of the utilitygrid would in turn impose constraints on thedesign of SPS. Integrating SPS into the grid in-volves several difficult system problems.

Microwave Transmission. —● Stability. Because a microwave SPS is an

electronic system, not a mechanical one,any power fluctuations due to beam-pointing errors or to large-scale compo-nent failure would be rapid (the order of asecond or less). The rest of the grid wouldonly be able to respond relatively slowly(minutes), creating difficulties in control-ling the frequency of current and overallpower levels in the grid. The importanceof this difficulty is directly dependent onthe size of the SPS contribution. Thesmaller the output from a satellite-rectenna combination, the easier it will beto control. Some, if not all of this draw-back of the microwave system could bealleviated by including short-term batterystorage to act as a buffer between the SPSrectenna output and the grid. The stabilityof the grid would not then depend on thestability of the microwave mode of trans-mission. However, buffer storage wouldincrease system costs. The optimumamount of storage that might be neededhas not been determined, but cost esti-mates range from 0.5 to 5 percent of thetotal system costs.Load following and variations of SPS pow-er. The rectenna output would vary sea-sonally depending on the distance of theEarth from the Sun. The amount of thevariation, and the rate at which SPS powerchanges, would in principle pose no tech-nical problem for the grid.

Because any satellite that lies in a geo-stationary orbit experiences eclipses (1 to72 minutes) around the equinoxes (March

●

21 and September 21) when the Earth’sshadow falls across the satellite, a refer-ence system satellite would suffer powerinterruption. A number of satellites wouldbe eclipsed at one time. The rate at whichthe eclipsing occurs would cause the SPSpower to fall at a rate of about 20 percentper minute, much faster than the utilitygrids are expected to be able to respond.This could be alleviated by shutting thesatellite down slowly in advance of theshadow, with a consequent extra smallloss of SPS power for the period, or byincluding buffer storage as suggestedabove. If daily load curves maintain theircurrent shape, the eclipse would occurnear the daily minimum (local midnight),necessitating less backup capacity thanwouId otherwise be the case.

In principle, SPS could be designed tofollow the daily load, but because of itshigh capital costs it would be uneco-nomical to do so. It is designed to delivercontinuous, baseload power. Hence theburden of following any shifts in loadwould be placed on conventional terres-trial intermediate load units in the utilitysystem.Microwave beam positional errors. Thebeam could be centered on the rectennaby means of a pilot beam directed to-wards the satellite antenna from thecenter of the rectenna. Because the signalwould take about 0.2 seconds to sense aposition error and correct the pointing ofthe beam, the antenna output would besubject to a potential frequency variationof about 5Hz (5 cycles/see). Power varia-tions of tens of megawatts from thissource could make utility grid management extremely difficult. Weather frontscould adversely affect the position of thebeam, but the resultant power variationwould be slow. Again, buffer storagecould be used to alleviate these dif-ficulties.

Because the difficulties posed by each ofthe above factors increase with size, theutilities might not find the single 5,000-MWunit proposed by the reference system accept-


able even in the future. Although nuclear, fu-sion, or coal energy parks having about 5,000MW total capacity have been proposed, theywould be composed of several smaller units,each of which are only about 1,000-MW capac-ity. In addition, in planning for overall systemreliability, utilities generally use the criterionthat no single unit in the system can accountfor more than 10 to 15 percent of the totalsystem. Thus, in order to place a 5,000-MWunit in the grid, the grid should have a totalsystem capacity of 33,000 to 50,000 MW. Atcurrent rates of electrical growth (3.2 percentper year), only the Tennessee Valley Authority(TVA), the country’s largest utility, will have agrid large enough to accommodate a 5,000-MW SPS in 2000. TVA currently has a capacityof 23,000 MW, but it has stopped constructionon several new powerplants because of slowerdemand growth. A national power grid mightalleviate the problem of utility grids being toosmall to accommodate a 5,000-MW SPS.

Laser Transmission.— From the utilities’ per-spective, the most serious difficulty facinglaser transmission is absorption by clouds.Although in a few locations in the country itappears to be technically possible to switchfrom a cloud covered area to one that is cloud-free, utilities would have little incentive toconstruct the extra facilities to accommodatesuch switching unless the economic benefitswere commensurate with the expense of theextra facilities. In general, the various sites areunlikely to be all in the same service area, fur-ther complicating the ability of the utility tofollow the load.

Mirror Reflection. —●

●

Reflection of sunlight from space suffersfrom the same disadvantage as that of thelaser option: the reflected beam couldeasily be degraded or occluded by cloudcover. it has been suggested that the addi-tional radiant energy might be enough todissipate clouds, but this might havedetrimental environmental effects andalter weather patterns over a wide regionaround the energy park.As conceived in the “baseline” case, themirror system would require large energy

parks capable of producing more than 100GW. Smaller parks of 10 GW might alsobe possible. Even the relatively smallerparks would necessitate major changes incurrent utility operation and load man-agement. Among other changes, suchparks would necessitate building an exten-sive new network of major transmissionlines to distribute electrical power fromremote receiving areas to end-users.

In principle, all of the technical problemsfor the different systems are resolvable atsome cost. However, they would require con-siderable further study and testing as well as aclose look at the system economics.

Nontechnical Considerations

In addition to the technical difficulties thatSPS can be expected to face, there are anumber of potential institutional barriers toSPS acceptance by U.S. utilities:

●

●

SP5 as a space system. The current utilitymanagement and regulatory infrastruc-ture is much more receptive to the ter-restrial renewable or inexhaustible op-tions— breeder reactor and fusion forbaseload, and solar thermal and solarphotovoltaic for intermediate and peak-ing loads.Regulatory framework. Utilities are cur-rently regulated on a State or local basis.SPS could be expected to hasten the movetowards greater centralization of the reg-ulatory process (i.e. Federal level). ASOLARES-type SPS, because of its largecentralized energy parks, would make ahigh degree of centralization mandatory.However, other SPS modes may also leadto more centralized regulation, particu-larly if the SPS were constructed and man-aged by a federally chartered monopoly(see Ownership and Finance) or Govern-ment agency.

Nuclear powerplants are currently regu-lated at the Federal and State level forhealth, safety, and environmental im-pacts. However, their effect on the ratestructure is regulated at the State and


local level. An SPS corporation might leadto Federal involvement in setting rates forpower as well as regulating SPS technol-ogy. The utilities and local regulatoryagencies could be expected to resist anypressures toward greater Federal involve-ment in what has traditionally been theirprovince.

Ownership and Finance

Electric utilities currently face a seriousproblem raising the capital necessary to installnew generating capacity. Because of this, andbecause they lack launch and space construc-tion capability, they are unlikely to own oroperate the space segment of an SPS systemdirectly; they could more easily be responsiblefor the ground receivers. This raises the ques-tion of how domestic SPSs would be financedand managed.

The central issues are: 1 ) the degree and kindof government involvement; and 2) how to dif-ferentiate between the R&D and construction/operation phases.

● Government involvement. The argumentsfor Government financing and ownershipwouId be that the high fronnt-end costs andhigh-risk long pay-back times inhibit pri-vate sector investment, and that lack ofcompetition would necessitate Govern-ment ownership. Certain aspects of TVAor NASA could provide possible guidancefor SPS ownership and operation.

On the other hand, it can be argued thatdirect Government involvement is con-trary to American preference for privateenterprise, that centralized control wouldlead to inefficiencies, and that U.S. Gov-ernment ownership would make militaryparticipation far more likely. Further-more, it is feared that Government invest-ment in SPS would drain resources fromother energy technologies that needFederal support. A Government-charteredbut privately owned and operated com-pany similar to Comsat, or a regulatedprivate monopoly such as AT&T, might bepreferred. Since the United States is party

to international law that requires nationalgovernments to bear the responsibility forspace activities, even when carried out bynongovernmental entities, some degree ofFederal supervision and involvement willbe required in any case.R&D and operating phases. Raising privatecapital would be especially difficult dur-ing the research, development, and dem-onstration phase. A successful prototypedemonstration would probably be nec-essary to attract private investment. If SPSis judged to be a feasible energy option,prototype development is likely to requireFederal funding, perhaps via taxes, similarto the Interstate Highway System trustfund, or through “Space Bonds.” Afterthat, it is likely that Government loans orguarantees would be required, at a mini-mum. At some stage the technology couldbe turned over to the private sector. In-stances of such practices have includednuclear reactors, first developed for mili-tary use in submarines; and telecommuni-cations technology, funded by NASA andthen turned over to Comsat and commer-cial carriers. Clarification of current pat-ent provisions for NASA and other Gov-ernment research contracts would facili-tate such transfers. Upcoming examplesthat should be examined for their appli-cability to SPS are the Space Shuttle,which has been developed by NASA butmay eventually be turned over to privateenterprise, due to restrictions on NASAoperation of commercial ventures; thenewly established U.S. Synfuels Corp.,which is intended to provide money for avariety of private synthetic fuels ventures;and the European Space Agency’s (ESA)Ariane launcher, which will be operatedby a private consortium called Ariane-space. Private joint ventures, such asSatellite Business Systems or the Alaskapipeline consortium, are another possibleway to establish a “Solarsat” Corp. for theconstruction and operating phases.

A combination of the suggested mod-els, involving different degrees of Govern-ment and private financing, may be more


feasible than any of the specific models the ability of an SPS organization to at-mentioned. Providing for a smooth transi- tract foreign capital and to involve for-tion between public and private invest- eign participants at early stages of devel-ment phases would be an important con- opment. (See International Implications.)cern. A critical consideration should be

INTERNATIONAL IMPLICATIONS

What are the international implications ofsolar power satellites?*

Development and construction of an SPSsystem would necessarily involve a number ofinternational dimensions. At a minimum, cur-rent and future international treaties andagreements, especially those dealing with theallocation of the electromagnetic spectrum,would require consultation with foreign statesand multinational organizations. Beyond this,there may be good reasons to consider an ac-tive multilateral regime to regulate, build,and/or operate the SPS.

International organizations, multinationalcorporations, and domestic interest groups willall be involved in SPS decisions. However, dueto the SPS’s cost, benefits, and military/foreignpolicy impacts, which would directly affectthe vital national interests of other nations in-volved, such decisions will ultimately be madeat the national level by political leaders.

Economic lmpact.– If successful, the SPSpromises to deliver significant amounts ofelectricity y. Estimates of future global elec-tricity demand by the International Institutefor Applied Systems Analysis (IIASA) indicatethat, even with low rates of economic growth,electricity usage will increase by a factor of 4over the next 50 years. Regional variations ingrowth rates will be considerable, withdeveloped countries increasing at a muchslower rate than developing ones. Recentstudies for the United States that take into ac-count marked reductions in usage rates, suchas the National Academy of Sciences’ Energyin Transition 1985-2010 indicate that demandin the developed countries may remain con-

*See ch. 7.

stant or rise only SIightly over the next 30 years.On a global scale, this might indicate a rise lessthan that predicted by IIASA. Meeting this de-mand will be particularly difficult in energy-scarce areas such as Western Europe, Japan,and much of Latin America, Africa, and SouthAsia. Countries in these regions will beespecially interested in SPS development.

Noneconomic Impact. -The noneconomiceffects of SPS would influence the decisions ofthe major space powers, the United States andthe U.S.S.R. The prestige of such a major spaceand energy accomplishment would be consid-erable. The military advantages of high-capac-ity launch vehicles and a large energy-produc-ing platform in high orbit would be significant,even if SPS were not used for direct militarypurposes.

The United States and the U.S.S.R. bothhave extensive conventional energy sources–oil, coal, oil shale, and uranium. Thus, neithercountry can be expected to develop an SPSunilaterally unless unpredictable obstacles tothe use of coal and/or nuclear power develop.SPS is therefore likely to be pursued in con-junction with foreign partners who contributecapital and expertise and buy completed satel-lites. Both Western Europe and Japan, whohave extensive space programs and a history ofcooperation with the United States, would beprobable partners. Soviet secrecy and militarydomination of their space program makes in-ternational cooperation on their part unlikely.

International Cooperation.– Experience withmultilateral organizations suggests that estab-

I The global estimates cited in Energy in Transition, however,are similar to I IASA’S; a rise of three to five times in electricityconsumption by 2010. See Energy in Transition, NationalAcademy of Sciences, 1979, p. 626.


Iishing and running a successful internationalventure would be difficult. Reconciling the dif-ferent interests of the participants regardingoverall system design, decision making, andallocation of contracts and financial returnswould be time-consuming and might compro-mise timely and efficient results. The exampleof Intelsat suggests the importance of strongnational support by interested parties, ofindependent corporate management, and aprofit-incentive. However, it is unlikely that anagency modeled on Intel sat could be dupli-cated today for SPS. In particular, the role ofLDCs would be greater and could be disruptiveunless North-South conflicts can be kept fromdominating day-to-day decisions. Strongleadership by the United States and the Orga-nization of Economic Cooperative Devel-opment partners would be required to main-tain an effective program.

International Law.– International law cur-rently requires allocation of satellite frequen-cies and geostationary positions by the inter-national Telecommunication Union (ITU). IfSPS were to interfere with global communica-tions, this could be a major obstacle to gainingITU approval. ownership and control of thegeostationary orbit has not been completelyresolved, and attempts by equatorial states toclaim sovereignty over it could hamper devel-opment of any geostationary SPS. The propos-ed Moon Treaty, which calIs for an interna-tional regime based on the principle of theCommon Heritage of Mankind, provides aprecedent for international control over spaceresources, and may affect plans to constructSPS from lunar materials. In each of thesecases it can be expected that future LDCs willseek to gain leverage over any SPS regime bycontrolling access to space. AccommodatingLDC interests in a manner compatible with SPS

development may be difficult or politically im-possible; the precedent set by the uncom-pleted Law of the Sea negotiations should becarefulIy considered.

Military Impact. – The military uses of an SPS,especially for directed-energy weaponry,would be restricted by the 1972 Anti-BallisticMissile (ABM) Treaty and by provisions in the1967 Treaty on Principles Governing the Ac-tivities of States in the Exploration and Use ofOuter Space banning weapons of “massdestruction” in orbit. Although SPS would notlend itself to efficient use as a weapons-system, * objections to the SPS on militarygrounds, and demands for inspection and/orredesign to preclude military uses, can be ex-pected. Multilateral development would alle-viate many such problems.

Foreign Interests.—To date, space agenciesand private firms in foreign countries such asEngland, France, West Germany, and Japan,along with ESA, have expressed interest in SPS.Most foreign studies have focused on regionalapplications; technical and operational studieshave been done almost exclusively in theUnited States. Soviet interest has been ex-pressed for several years, with several tech-nical papers published, but no details areknown. Third World interest has been informaland cautiously favorable. Future discussion atthe United Nation’s Committee on the Peace-ful Uses of Outer Space and other interna-tional bodies will be forthcoming. Any furtherU.S.-sponsored study of SPSs must take intoaccount international participation in SPSdevelopment, and demand for SPS power, inorder to evaluate properly the feasibility ofSPS programs.

——.‘See ch 7, Military Uses of SPS section

NATIONAL SECURITY IMPLICATIONS

What are the national security implications The military importance of SPS would deriveof SPS?* from its very large size, its geostationary or-

bital position (for certain designs), and its abili-ty to provide tremendous amounts of power.

*For extended discussion see ch, 7 Aside from the important result of reducing


the user state’s dependence on importedenergy, SPS would be strategically significantas a target, as the catalyst for new spacetransportation and construction capabilities,and as a possible weapons-system.

Vulnerability. –A full-scale SPS systemwouId constitute a high-value target for enemyaction. Whether an SPS would in fact betargeted in the event of hostilities will dependabove all on how crucial it is to a country’selectrical supply. Can SPS power be made upfrom other sources? Is the attacker vulnerableto a counter-attack in kind? Best estimates arethat an SPS system would be unlikely to con-stitute more than 10 to 20 percent of totalgenerating capacity, in the countries that useSPS, over the next 50 years. Holding SPS to thispercent would make it possible to replace SPSpower from conventional reserve capacity.However, usage could be much higher in spe-cific regions or industries. A widespread na-tional grid could alleviate the threat of SPSoutages. In general, SPS would be no moreVuInerable than other major energy systems.

SPSs could be attacked in a number of ways:1) by ground-launched missiles carrying nu-clear or conventional warheads, 2) by orbitingantisatellite platforms, 3) by ground- or space-based directed-energy weapons, 4) by strewingdebris in the satellite’s path, and 5) by inter-fering with or redirecting the SPS’s energytransmission beam.

The large size of most SPS options wouldmake it difficuIt for conventional explosives todo serious damage. Lasers would likely bemore effective. Strewing debris in geosyn-chronous orbit would destroy a referencesystem SPS, but also affect many other targets,including friendly and neutral spacecraft.Beam interference would be less damagingand would require special preparation to pro-tect against. Nuclear weapons could damageSPSs by direct blast, and also by the electro-magnetic pulse (EMP) effect, which mightoverload the satellite’s electrical systems — alarge (1 megaton or more) nuclear explosioncould damage a photovoltaic SPS at ranges upto hundreds of kilometers.

The use of nuclear weapons outside of a ma-jor nuclear exchange would carry great dan-gers of escalation. Any attack, nuclear or con-ventional, would depend on perceptions ofwhether SPS is considered part of national ter-ritory and how leaders would react to such aprovocation. The analogy to ships on the highsea suggests that an SPS in orbit might be con-sidered fair game even short of full-scale war.Attacks on SPS would also be affected bywhether the SPS was manned; destroying anunmanned craft might be undertaken as a rela-tively unprovocative demonstration of will. Atpresent, neither the United States nor theU.S.S.R. has the ability to attack objects ingeosynchronous orbit, but both are working onvarious antisatellite devices and there appearto be no insurmountable obstacles to theirdevelopment.

Defense of space craft is possible through:1) maneuverability, 2) hardening, and 3) anti-missile defenses.

The SPS would be too large and fragile toevade attack. Hardening against explosives orEMP bursts would add significantly to weightand costs, and could not be effective against adetermined attack. Stationing missile or satel-lite defenses on a geostationary SPS, whetherdirected-energy weapons or antimissile mis-siles, would be feasible due to the powergenerated by the SPS and its position at the topof a 35,800-km “gravity well”. However, suchweapons would have unavoidable offensivecapabilities and would therefore invite attack.Defense of civilian SPSs could probably bebest done by independent military forces, onthe ground or in space, rather than by turningthe SPS itself into a space-fortress.

Receiving antennas or (for the mirror-system) PV ‘parks’ would make unattractivetargets due to their large size and redundancy;they would certainly be no more vulnerablethan other generating facilities. It should benoted that the SOLARES system could con-tinue to produce power, albeit at approximate-ly one-fifth rated capacity, by operating onambient sunlight even if the space mirrorsystem were destroyed.


Military Uses. –The military usefulness of anSPS stems from: 1) the launchers and other fa-cilities used to construct the satellite portion;2) the energy beams used by the SPS to trans-mit power; and 3) its strategic orbital location.

HLLVS or other transportation and construc-tion systems would be perhaps the most directmilitary benefit of SPS. These could be used bythe military to build large space platforms forcommunications, surveillance, or weaponry.Such activities might be disguised by beingcarried out during SPS construction, but it isunlikely that they could escape detection byinterested parties. Development of such sys-tems would be most important, and destabiliz-ing, in providing a “break-out” capacity forrapid emergency deployment of military satel-lites by fleets of SPS construction vehicles.

Laser beams built as part of SPS, or moremilitarily efficient weapons placed on the SPSbut not used in transmitting electricity, couldbe used as strategic weapons. In recent yearsboth the United States and the U.S.S.R. haveundertaken large programs to develop di-rected-energy weapons for use against satel-lites and/or international ballistic missiles(ICBMs). However, a geostationary SPS is35,800 kilometers distant from low-flyingICBMs. This distance complicates tracking andrequires very high beam intensities. Muchgreater effectiveness can be achieved byweapons placed in lower orbits. However, ageostationary SPS could play a role in supply-ing power to remotely located directed-energyplatforms. A laser SPS in low Sun-synchronousorbit, of course, would represent a muchgreater military potential than one in geosyn-chronous orbit.

Use of SPS, even indirectly, for ABM pur-poses is currently prohibited by the 1972 ABMTreaty. A militarily effective SPS would be amajor factor in strategic planning and wouldlikely be a subject of arms-control negotiationsbetween interested states. Provisions for directinspection, or design specifications to reducean SPS’s military usefulness, could be negoti-ated to reduce the various threats it poses.

Such provisions might be needed even if SPSwould not be militarily useful, but was never-theless perceived to be a military or politicalthreat.

Using an SPS directly against targets on theground would ease tracking requirements.High-energy lasers (H EL) or particle-beamscould conceivably be used to destroy quicklytactical targets such as ships, planes, or oilrefineries without jeopardizing one’s own per-sonnel or risking the use of nuclear weapons.However, SPS lasers used for energy transmis-sion would probably not make effectiveweapons without considerable modification.SPS could also be used to supply electricalpower to military units in remote areas, andperhaps even directly to ships or planes.

SPS could serve as a platform for certainsurveillance and communications needs. Be-cause of its power, it might be especiallysuited for conducting jamming and electronicwarfare operations.

SPS platforms, because of their size andfacilities, would be likely to serve as multipur-pose space bases similar to major seaports. Ifmilitary units used SPS for resupply or rest andrecreation, it might be difficult to separatemilitary from civilian uses, or to convince out-side observers that SPS was not a militarythreat.

Any such direct uses of SPS would be deter-mined by the way in which future SPSs arebuilt and managed. Construction by an inde-pendent multinational enterprise would re-duce any state’s ability to use an SPS for mili-tary purposes; conversely, unilateral devel-opment would enhance it. Use of SPSs asweapons platforms by future superpowerswould invite considerable foreign criticism,especially if such attempts interfered withtheir electricity-generation function. A suddendiversion of SPS power to the military in timeof crisis could lead to domestic and/or foreignelectricity shortages, resulting in legal ordiplomatic protests.


PUBLIC

The SPS debate: what are the issues arising inthe public arena?*

While public awareness of SPS is growing,most discussion has been confined to a smallnumber of public interest groups and profes-sional societies. In general, many of the in-dividuals and groups who support the develop-ment of SPS also advocate a vigorous spaceprogram. The L-5 Society has been a particu-larly vocal SPS supporter and views thesatelIite system as an important stepping-stonein the colonization of space, a goal to whichthe society is dedicated. The SUNSAT EnergyCouncil, a group formed to promote interest inSPS, believes that it is one of the most promis-ing options available for meeting future globalenergy and resource needs. Professional asso-ciations such as the American Institute ofAeronautics and Astronautics (AIAA) and theInstitute of Electrical and Electronics Engi-neers (1 E E E), have supported continued re-search and evaluation of the concept.

Many opponents of SPS are concerned thatit wouId drain resources from the developmentof terrestrial solar technologies. The Solar Lob-by and other public interest groups argue thatcompared to these ground-based solar options,SPS is inordinately large, expensive, and com-

‘See ch 9, Issues Arising in the Public Arena section

ENVIRONMENT

How would SPS affect human health and theenvironment?*

As an energy system operating both in spaceand on Earth, SPS involves some rather diverseand unique environmental issues (see table 3).While one advantage of SPS is that it wouldavoid many of the environmental risks typi-cally related to conventional energy optionssuch as nuclear and coal, it would alsogenerate some unconventional environmental

*See ch. 8.

8 3 - 3 1 6 0 - 8 1 - 4

ISSUES

plex, and that it poses greater environmentaland military risks while precluding local deci-sionmaking. Many opponents also maintainthat all future energy demand can be easilymet with existing and future terrestrial energytechnologies; there is little need to developSPS, especially in view of the formidable coststo initiate the technology and the highly uncer-tain cost of the product. The Citizen’s EnergyProject (CEP) has been an active lobbyistagainst Government funding of SPS and hascoordinated the Coalition Against SatellitePower Systems, a network of solar and environ-mental organizations. Objections to SPS havealso been raised by individuals in the profes-sional astronomy and space science com-munities who see SPS as a threat to the fundingand practice of their respective sciences. In thefuture, it is conceivable that antinuclear, anti-military and tax groups could also join the op-position.

Public opinion about SPS can be influencedby a multitude of factors; concerns articulatedtoday may not be as important in the future. Inaddition, in much of the current public discus-sion, SPS is treated as a U.S. system alone. IfSPS were to be developed on an internationalbasis, the flavor of present opinion couldchange. Currently, debate about SPS focuseson the question of R&D funding. This andother issues are highlighted in table 2.

AND HEALTH

effects which are poorly understood at pres-ent. The resolution of the uncertaintiesassociated with these effects is critical to theassessment of the environmental acceptabilityof SPS. More research is needed to understandand quantify these impacts and to investigatemodified system designs that would minimizeenvironmental risks. At present, there are threemajor areas of concern.

1. Bioeffects of Electromagnetic Radiation.—The effects of exposure to SPS power trans-mission and high-voltage transmission lines


Table 2.—Major Issues Arising in SPS Debatea

Pro

R&D funding. SPS is a promising energy option ●

. The Nation should keep as many energy options open as ●

possible● An SPS R&D program is the only means of evaluating the merit ●

of SPS relative to other energy technologies● SPS R&D will yield spinoffs to other programs

cost● SPS is likely to be cost competitive in the energy market ●

. Cost to taxpayer is for R&D onIy and accounts for smalI portion ●

of total cost; private sector and/or other nations will invest in pro-duction and maintenance

. SPS will produce economic spinoffs

Environment, health and safety● SPS is potentialIy less harsh on the environment than other

energy technologies, especially coal

Space● Space is the optimum place to harvest sunlight and other

resources● SPS could be an important component or focus for a space

program. SPS could lay the groundwork for space industrialization and/or

colonization. SPS would produce spinoffs from R&D and hardware to other

space and terrestrial programsInternational considerations● One of the most attractive characteristics of SPS is its potential

for international cooperation and ownership. SPS can contribute significantly to the global energy supply. SPS is one of the few options for Europe and Japan and is well-

-suited to meet the energy and resource needs of developingnations

● An international SPS wouId reduce concerns about adversemilitary implications

Military implications● The vulnerability of SPS is comparable to other energy systems● SPS has poor weapons potential• As a civilian program, SPS would create little military spinoffs

Centralization and scale● Future energy needs include large as well as small-scale supply

technologies; urban centers and industry especially cannot bepowered by small-scale systems alone

. SPS would fit easily into an already centralized grid

Future energy demand● Future electricity demand will be much higher than today● High energy consumption is required for economic growth● SPS as one of a number of future electricity sources can con-

tribute significantly to energy needs. Even if domestic demand for SPS is low, there is a global need

for SPS

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

SPS is a very high-risk, unattractive technologyOther more viable and preferable energy options exist to meet ourfuture energy demandSPS would drain resources from other programs, especially ter-restrial solar technologies and the space sciencesNo matter what the result of R&D, bureaucratic inertia will carry aGovernment program too far

SPS is unlikely to be cost competitive without Government subsidyLike the nuclear industry, SPS would probably require ongoingGovernment commitmentProjected costs are probably underestimated considerablyThe amount of energy supplied by SPS does not justify the cost

SPS risks to humans and the environment are potentially greaterthan those associated with terrestrial solar technologiesMajor concerns include: health hazards of power transmission andhigh-voltage transmission lines, land use, electromagnetic inter-ference, upper atmosphere effects, and “skylab syndrome”

SPS is an aerospace boondoggle; there are better routes to spaceindustrialization and exploration than SPSSPS is an energy system and should not be justified on the basisof its applicability to space projects

SPS could represent a form of U.S. of industrial nations’ “energyimperialism”; it is not suitable for LDCsOwnership of SPS by multinational corporations would centralizepower

Spinoffs to the military from R&D and hardware would be signifi-cant and undesirableVulnerability and weapons potential are of concern

SPS would augment and necessitate a centralized infrastructureand reduce local control, ownership, and participation in decision-makingThe incremental risk of investing in SPS development is unaccept-ably high

Future electricity demand could be comparable to or only slightlyhigher than today’s with conservationThe standard of living can be maintained with a lower rate ofenergy consumptionThere is little need for SPS; demand can be met easily by existingtechnologies and conservationBy investing in SPS development, we are guaranteeing high energyconsumption, because the costs of development would be so great

arguments mainly focus on the SPS reference sYstem


Ch. 3—Issues and Findings ● 4 3

Table 3.—Summary of SPS Environmental Impacts

System componentcharacteristics Environmental impact

Occupational healthPublic health and safety and safety

Power transmissionMicrowave — bIonospheric heating could

disrupt telecommunications.Maximum tolerable powerdensity is not known.Effects in the upperionosphere are not known.

—Tropospheric heating couldresult in minor weathermodification.

—bEcosystem: microwave bio-effects (on plants, animals,and airborne biota) largelyunknown; reflected lighteffects unknown.

— bpotential in te r fe rence w i th

satellite communications,terrestrial communications,radar, radio, and opticalastronomy.

— bEffects of Iow-level —Higher risk than forchronic exposure to micro- public; protectivewaves are unknown. clothing required for

— Psychological effects of terrestrial worker.microwave beam as weapon. —Accidental exposure to

—Adverse aesthetic effects high-intensity beam inon appearance of night sky. space potentially severe

but no data.

Lasers

Mirrors


Launch and recovery

HLLVPLVCOTVPOTV

—Tropospheric heating couldmodify weather and spreadthe beam.

—Ecosystem: beam mayincinerate birds andvegetation.

— bpotential interferencewith optical astronomy,some interference withradio astronomy.

— bTropospheric heatingcould modify weather.

—Ecosystem: effect of 24-hr Iight on growing.cycles of plants and cir-cadian rhythms of animals.

— bpotential interferencewit h optical astronomy.

—Ground cloud might polluteair and water and causepossible weather modi-fication; acid rainprobably negligible.

— bWater vapor and otherlaunch effluents coulddeplete ionosphere andenhance airglow. Result-ant disruption of com-munications and satellitesurveillance potentialyimportant, but uncertain.

— bpossible format ion ofnoctilucent clouds instratosphere and meso-sphere; effects on climateare not known.

—Ocular hazard?—Psychological effects of

laser as weapon arepossible.

—Adverse aesthetic effectson appearance of nightsky are possible.

—Ocular hazard?—Psychological effect of

24-hr sunlight.— bA d v e r s e aes the t i c e f f e c t s

on appearance of nightsky are possible.

—Noise (sonic boom) mayexceed EPA guidelines.

—Ground cloud might affectair quality; acid rainprobably negligible.

—Accidents-catastrophicexplosion near launchsite, vehicle crash, toxicmaterials.

—Ocular and safetyhazard?

—Ocular hazard?

— bSpace worker’s h a z a r d s :ionizing radiation(potentially severe)weightlessness, lifesupport failure, longstay in space,construction accidentspsychological stress,acceleration.

—Terrestrial worker’shazards: noise, trans-portation accidents.

44 ● Solar Power Satel l i tes

Table 3.—Summary of SPS Environmental Impacts—Continued

System component Occupational healthcharacteristics Environmental impact Public health and safety and safety

— bEmission of water vaporcould alter naturalhydrogen cycle; extent andimplications are not well-known.

—bEffect of COTV argon ionson magnetosphere andplasma-sphere could begreat but unknown.

—Depletion of ozone layerby effluents expected tobe minor but uncertain.

—Noise.

Terrestrial activitiesMining —Land disturbance —Toxic material exposure. —Occupational air and

(stripmining, etc.). — Measurable increase of water pollution.—Measurable increase of air and water pollution. —Toxic materials exposure.

air and water pollution. — Land-use disturbance. —Noise.—Solid waste generation.—Strain on production

capacity of galliumarsenide, sapphire, silicon,graphite fiber, tungsten,and mercury.

Manufacturing —Measurable increase of —Measurable increase of —Toxic materials exposure.air and water pollution. air and water pollution. —Noise.

—Solid wastes. —Solid wastes.—Exposure to toxic

materials.

Construction —Measurable Iand —Measurable land —Noise.disturbance. disturbance. —Measurable local

—Measurable local increase —Measurable local increase increase of air and waterof air and water pollution. of air and water pollution. pollution.

—Accidents.

Receiving antenna — bLand use and siting. — b L a n d u s e — r e d u c e d — Waste heat.—Waste heat and surface property value, aesthetics,

roughness could modify vulnerability (less landweather. for solid-state, laser

opt ions; more for referenceand mirrors).

High-voltage — bLand use and siting. — bExposure to high intensity —bExposure to hightransmission lines — bEcosystem: bioeffects Of EM fields—effects intensity EM fields—(not unique to SPS) powerlines uncertain. uncertain. effects uncertain.

almpacts based on SPS systems as currently defined ancl do not account for offshore receivers or poss!ble miti9atin9 sYstem modifications.bResearch priority.SOURCE: Office of Technology Assessment.


(HVTL) on humans, animals, and plants arehighly uncertain. The existing data base is in-complete, often contradictory and not directlyapplicable to SPS. While the thermal effects ofmicrowave radiation (i. e., heating) are well-understood, research is critically needed tostudy the consequences of chronic exposure tolow-level microwaves such as might be ex-perienced by workers or the public outside ofthe receiver site. The biological systems thatmay be most susceptible to microwavesinclude the immunological, hematological(blood), reproductive, and central nervous sys-tems. The DOE SPS assessment has sponsoredthree studies of the effects of low-level micro-waves on bees, birds, and small mammals. Nosignificant effects have been observed, but theexperiments are far from complete. More re-search is vitally needed to expand the experi-mental and clinical data base, and to improvetheories which may facilitate the extrapolationfrom animal studies to assessments of humanhealth hazards.

It appears that the United States will estab-lish a microwave standard in the near futurethat is more stringent than the present occupa-tional 10.0 mW/cm2 voluntary guideline (thenew occupational standard at 2.45 GHz willprobably be 5.0 mW/cm2), thereby approach-ing the standards in other countries (e. g.,Canada: population —1.0 mW/cm2, occupa-tional —5.0 mW/cm2; U. S. S. R.: population—0.001 mW/cm2, occupational —0.01 mW/cm2).This does not have an immediate impact onSPS Iand use for the reference system, since itis designed to produce less than 1.0 mW/cm2 atthe rectenna boundary and less than 0.1 mW/cm2 outside the rectenna boundary. Neverthe-less, establishing population standards that aremore stringent couId mean more land for eachbuffer zone and could affect system design(power density and beam taper) as well aspublic opinion.

With respect to spaceworkers, exposure toionizing radiation (including that from theradiation belts, galactic cosmic rays, and solarflares) would be a health hazard unless stepsare taken in future planning to minimize dose.Studies are needed to determine acceptable

exposure limits. Research is needed to deter-mine more precisely the expected dose rates,the types and energies of ionizing particles,and the effectiveness rate of various types andthicknesses of shielding. The results will deter-mine the number of spaceworkers, the dura-tion of the stay, the mass needed in orbit (forshielding), and space suit and system designs.All of these impacts may strongly affect SPScosts and feasibility.

For SPS systems other than the microwavedesigns, very little assessment of the healthand safety effects has been conducted. Thepower density of a focused laser system beamcould be sufficiently great to incinerate somebiological matter. Outside the beam, scatteredlaser light could constitute an ocular and skinhazard. More study would be needed to quan-tify risks, define possible safety measures andexplore the effects of long-term exposure tolow-level laser light.

The light delivered to Earth by the mirrorsystem, even in combination with the ambientdaylight, would never exceed that in the desertat high noon. The health impacts that might beadverse include psychological and physiologi-cal effects of 24 hour per day sunlight andpossible ocular damage from viewing the mir-rors, expecialIy through binoculars.

2. Effects on the Upper Atmosphere.– Atmos-pheric effects result from two sources: heatingby the power transmission beam and the emis-sion of launch vehicle effluents. While themost significant effect of the laser and mirrorsystems is probably weather modification dueto tropospheric heating, ionospheric heating ismost important for the microwave systemsoperating at 2.45 GHz. Of most concern isdisruption of telecommunications and surveil-lance systems from perturbations of the iono-sphere. Experiments indicate that the effectson telecommunications of heating the lowerionosphere are negligible for the systemstested. As a result, a few researchers have sug-gested that microwave power densities of upto 40 to 50 mW/cm2, or two times the levelassumed for the reference design, could beused before significant heating would occur.


The largest uncertainty is related to heatingand nonlinear interactions in the upper iono-sphere. To investigate the heating effects inthis region, more powerful heating facilitieswould be required.

The atmospheric effects resulting from theemission of rocket effluents from SPS spacevehicles are of concern because of the un-precedented magnitude and frequency of theprojected SPS launches. In the magnetosphere,construction of the SPS reference system aspresently designed would lead to a dramaticincrease in the naturally occurring abundanceof argon ions (from the electric propulsionsystem proposed for orbital transfer) andhydrogen atoms. While several possible effectshave been identified, including enhanced air-glow and Van Allen belt radiation, and alteredatmospheric electricity and weather, the likeli-hood and severity of these effects are highlyuncertain.

The injection of water vapor at lower alti-tudes would significantly increase the watercontent relative to natural levels. One possibleconsequence is an increase in the upward fluxof hydrogen atoms through the thermosphere.Another consequence of increasing the con-centration of water in the upper atmospheremight be the formation of noctilucent cloudsin the mesosphere. While global climatic ef-fects of these clouds appear unlikely, uncer-tainties remain.

The injection of rocket exhaust, particularlywater vapor, into the ionosphere could lead tothe depletion of large areas of the ionosphere.These “ionospheric holes” could degrade tele-communication systems that rely on the iono-sphere. While the uncertainties are greatest forthe lower ionosphere, experiments are neededto test more adequately telecommunicationsimpacts and to improve our theoretical under-standing of chemical-electrical interactionsthroughout the ionosphere.

In the troposphere, ground clouds generatedduring liftoff could modify local weather andair quality on a short-term basis.

Additional experiments and improved at-mospheric theory are needed to understand

and quantify the above impacts under SPSconditions. In addition mitigating steps such astrajectory control, alternate space vehicledesign, and the mining of lunar materials needto be assessed. Atmospheric studies wouldplay a major role in the choice of frequencyfor power transmission.

3. Land Use and Receiver Siting.– Receiversiting could be a major issue for each of theland-based SPS systems. Offshore siting andmultiple use siting might each alleviate someof the difficulties associated with dedicatedland-based receivers, but require further study.There are two components to the siting issue:technical and political. Tradeoffs must bemade between a number of technical criteria:1) finding geographically and meteorologicallysuitable areas; 2) finding sparsely populatedareas; 3) keeping down the cost of power trans-mission lines and transportation to the con-struction site; 4) siting as close to the Equatoras possible (for GEO systems) so as to keep thenorth-south dimension of the receiver rea-sonably small; 5) coordinating receiver siteswith utility grids and the regional need forelectricity; 6) the cost of land; and 7) ensuringthat the receivers are sited away from criticaland sensitive facilities that might suffer fromelectromagnetic interference from SPS, e.g.,military, communications, and nuclear powerinstallations. In addition, for the reference andSOLARES systems, as presently designed, largecontiguous plots of land would have to belocated and totally dedicated to one use (table4). The laser options might require less landarea per site, but a greater number of sites todeliver the comparable amount of power.

It is clear that the choice of frequency,ionospheric heating limits, and radiationstandards could have an impact on the land re-quirements. Further study is needed to under-stand fully the environmental and economicimpacts of a receiver system on candidate sitesand to determine if enough sites can belocated to satisfy the technical requirements.In addition the plausibility of multiple uses(e.g., agriculture or aquiculture), offshoresiting (especially for land-scarce areas such as

Ch. 3—Issues and Findings ● 4 7

Table 4.—SPS Systems Land UseNumber of sites Total land area(km2)

SPS system k m2/site km2/1,OOOMW for 300,000 MW for 300,000 MW m2/MW-yr

Reference . . . . . . . . . . . 174 35.0 60 10,400 1,233 b

Solid statec . . . . . . . . . . . 50 33.0 180 9,000 1,163 b

Laser Id. . . . . . . . . . . . . . . 0 1.2 600 360 42-51e

Laser lId. . . . . . . . . . . . . . 40 80.0 600 24,000 2,819-3,382 e

Mirror I . . . . . . . . . . . . . . . 1,000 - 2 9 2,200 261-313 e

Mirror Ilf. . . . . . . . . . . . . . 100 9.6 30 2,880 338-406 e

For comparisonWashington. . . . . . . . . . . 174.0New York City. . . . . . . . . 950.0Chicago. . . . . . . . . . . . . . 518.0aR~~t~nna at 34. latitude ~over~ a 117 km, e(lipitical area, Mi~r~~ave power density at edge of rectenna is 1.(J mw/cm2, If an exclusion boundary is set at 0.1 mW/Cm2,

then the total land per site is approximately 174 km2. J. B. Blackburn, Sate//ire Power System (SPS) Mapping of Exc/usion Areas for Rectenna Sites, DOE/NASA ReportHCP/R-4024-10, October 1978 does not include land for mining or fuel transport.bThe values for the reference and solid-state designs assume a 30-year lifetime and a caPacitY factor of 0.9cThe solid-state sandwich design is described in G. M. Hanley et al., “Satellite Power Systems (SPS) Concept Definition Study, ” First Performance Review, Rockwell in-ternational Report No. SSD79-0163, NASA MSFC Contract NAS8-32475, October 10, 1979.dLaser 1 and Laser II are two laser systems considered by DOE Both deliver the same amount of power but the beam of Laser I is more narrow (and hence rllore intenSe)

than that of Laser Il. See C. Bain, Potential of Laser for SPS Power Transmission, October 1978, Department of Energy, HCPIR-4024-07.eThe values for the laser and mirror systems assume a 30-year lifetime and CapaCitY factors of 0.75-0.9.fMirror I system parameters are defined by SOLARES “baseline system” and Mirror II system for low (1 ,100 km) orbitgThe SOLARES baseline system is designed to deliver 81O GW to 6 sites; 2 SOLARES basellne sites actually provide 270 GW.

the Northeast United States, Europe, andJapan) and possible receiver siting in other na-tions, with their particular environmental con-straints, need to be explored.

The regional political problems may bemore severe than the technical ones, especial-ly in light of past controversies over the sitingof powerplants, powerlines, and military radarand other facilities. While the constructionand operation of receivers might be welcomedby some communities on the basis of eco-nomic benefit, others might oppose nearby re-ceiver siting for a number of reasons, in-cluding: environmental, health and safetyrisks; fear that the receiver would be a targetfor nuclear attack; fear of decreased landvalues; preference for an alternate use of theland; objection to the receiver’s visibility; andfor rural Americans, resistance to the intrusionof urban life.

It is essential that many of the environmen-tal uncertainties be diminished and that theeffects are shown to be, at worst, comparableto those of alternate inexhaustible energysources, before commitment to the develop-ment of SPS because:

1. environmental effects may be identifiedfor which there are no acceptable mitiga-

2,

If

tion strategies or for which mitigation istoo costly to make SPS competitive; andthey have a great bearing on the systemdesign, e.g., choice of frequency, powerlevel and distribution may be determinedby the results of bioeffect and atmos-pheric studies and these may in turn con-trol hardware design, cost, and land use.

an SPS program is pursued, the assessmentof environmental risks should receive thehighest research priority. Some studies such asbioeffects research may require substantialtime to complete; the resolution of environ-mental uncertainties could affect the develop-ment schedule of SPS. Much of the environ-mental research needed in the assessment ofSPS is applicable to other studies and would bevaluable whether or not an SPS program isundertaken. Conversely, many of the en-vironmental questions associated with SPS arealso being addressed in other “generic” re-search programs such as those investigatingmicrowave bioeffects and upper atmospherephysics. The delineation of which environmen-tal risks are most important would, to a largeextent, depend on the specific design conceptsthat showed the greatest promise.


ELECTROMAGNETIC COMPATIBILITY

How would SPS affect other users of theelectromagnetic spectrum?*

Whether SPS were to be eventually de-ployed as a microwave, laser, or mirror system,it would affect some portion of the elec-tromagnetic spectrum. Other users of the spec-trum would be concerned about the nature ofpotential detrimental effects, whether they areamenable to amelioration and, if so, what thecosts would be. A microwave system would bethe most problematic because communica-tions of all sorts share this general portion ofthe spectrum. In addition, a wide range ofother electronic devices (e. g., sensors, com-puters) are susceptible to microwave inter-ference.

The Public

Deploying SPS would markedly change thevisual appearance of the night sky. A set ofreference system satellites equally spacedalong the Equator would appear as a set ofbright stationary “stars” whose total effect forobservers on longitudes near the middle of theset and for all latitudes along these longitudelines would equal the Moon at about quarterphase. Nonstationary satellites such as an LEOdeployed laser or mirror system would createthe effect of bright moving “stars.” The effectof such satelIites on the night sky has not beencalculated. However, it could be expected toequal the overall effect of the 60-satellite setof reference satelIites.

Some observers might well enjoy the sight ofmanmade “stars” added to the night sky.Many, especially those in countries who failedto benefit from the generated power, mightstrongly resent the intrusion on the celestiallandscape.

Space Communications

All artificial Earth satellites use some por-tion of the electromagnetic spectrum for com-

‘See ch. 8

munication. Some also use the spectrum forremote sensing. All would be affected in someway by SPS.

Geosynchronous Satellites.– These would bemost strongly affected by the microwave sys-tems. They could be expected to experiencemicrowave interference from noise at the fun-damental SPS frequency (e.g., 2.45 Ghz for thereference design), spurious emission in nearbybands, harmonics of the fundamental SPS fre-quency, and from so-called intermodulationproducts. All radio frequency transmitters gen-erate such noise and receivers are designed tofilter out unwanted effects. However, themagnitude of the power level at the centralfrequency and in harmonic frequencies for amicrowave SPS is so great that the possibilityof degrading the performance of satellitereceivers and transmitters from these spuriouseffects is high.

In addition to the direct effects from micro-wave power transmissions, geosynchronoussatellites could also experience “multipath in-terference” from geostationary power satel-lites due to their sheer size. In this effect, mi-crowave signals traveling in a straight line be-tween CEO communications satellites wouldexperience interference from the same signalreflected from the surface of the powersatelIite.

The sum of all these effects would result in alimit on the distance that a geosynchronoussatellite must have from the SPS in order tooperate effectively. The minimum necessaryspacing would depend directly on the physicaldesign of the satellite, the wave length atwhich it operated, and the type of transmissiondevice used (i.e., klystron, magnetron, solid-state device).

Since a microwave SPS would have to sharethe limited resource of the geostationary orbitwith other satellites, the value of the minimumspacing has emerged as one of the most crit-ical issues facing a geostationary SPS. How-ever, in the absence of a specific design, it isimpossible to characterize the exact form and


nature of the interference. Additional informa-tion is essential to calculate the minimum re-quired spacing. In addition, even if the designparameters were known accurately, the theoryof phased arrays is insufficiently developed to-day to predict the minimum distance. Esti-mates of the minimum necessary spacingrange from 1/2 0 to 10. The lower limit wouldprobably be acceptable. However, a minimumspacing much greater than 10 would result intoo few available geostationary slots to allowboth types of users to share the orbit unlessmany communications functions could be ac-commodated on a few large space platforms.

At present, some 80 satellites share thegeostationary orbit worldwide, and by 1990that number is expected to increase signifi-cantly (fig. 6). Even though improvements intechnology will lead to a reduction in the totalnumber of satellites necessary to carry thesame volume of communications services,total service is expected to rise dramatically.

Figure 6.—The Number of GeosynchronousSatellites as a Function of Time

1980 1985 1970 1975 1980 1985 1990

Year

SOURCE: W. L. Morgan, Comsat Technical Review, 10 vol. 1,1980.

At present the minimum spacing for domesticgeostationary satellites is 40 in the 4/6 GHzband and 30 in the 12/14 HGz band. At thesespacings, a maximum of 90 4/6 GHz band satel-lites and 120 12/14 GHz band satellites couldtheoretically coexist at geostationary alti-tudes, in the absence of SPS. Current researchactivity in the 20/30 GHz band is likely to leadto much greater capacity and smaller spacingsfor that band by the time an SPS might bedeployed. But even with these and other un-predictable advances in communications tech-nology in space and on the ground, competi-tion for geostationary orbit slots is likely to behigh.

The laser and mirror systems in low-Earth or-bit are unlikely to interfere with geosynchro-nous satellites except in the relatively improb-able event that one of the mirrors passes pre-cisely between the geosynchronous satelliteand its ground station, and even that interrup-tion would be for so short a time as to pose noserious problem.

Other Satellites. – In addition to geosynchro-nous satellites operating at the same altitudeas the CEO SPS, there are numerous militaryand civilian satellites in various low-Earth or-bits that might pass through an SPS microwavebeam. Such satellites could in principle pro-tect themselves from adverse interferencefrom the SPS beam by shutting down uplinkcommunications for that period, and improv-ing shielding for data and attitude sensors,computer modules, and control functions.Whether this action would be feasible dependson the particular mission the satelIite is to per-form. For some remote sensing satellites, ashutdown could mean loss of significant data.It would not be feasible for the SPS to shutdown for the few seconds of satellite passage.It might also be possible for many satellites tofIy orbits that will not intersect the SPS beam.

The laser and mirror systems might interferewith nongeosynchronous satellites by causingreflected sunlight to blind their optical sensorsor by passing through communications beams.Of the two systems, the mirror system would


cause the most problems because of the sizeof the mirrors and their orbital speed. To date,no one has calculated the possible adverse ef-fects due to this cause.

Deep Space Communications. – Becausedeep space probes generally travel in the planeof the solar system (known as the ecliptic),they would be especially affected by a geosta-tionary microwave SPS. A microwave SPSwould effectively prevent ground communica-tion with the probe when the latter happens tolie near the part of the ecliptic that crosses theEquator. This interference is especially seriousfor deep space vehicles because it is essentialto be able to communicate with them at anytime for the purposes of orbit control and fortimely retrieval of stored data.

It would be possible to avoid such inter-ference by establishing a communicationsbase for deep space probes in orbit. As wepenetrate deeper into space, this may be ad-visable for other reasons. If not, such a com-munications station would effectively add tothe cost of the SPS.

Terrestrial Communications andElectronic Systems

Both civilian and military terrestrial com-munications, radar, sensors, and computercomponents would suffer from a number ofpossible effects of a microwave beam. Directinterference can occur from the central fre-quency or the harmonics. In addition, scat-tered and reflected radiation at these frequen-cies from the rectenna, and rectenna emissionscould cause additional interference problemsfor terrestrial receivers. At the very least,rectennas would have to be located far enoughfrom critical sites such as airports, nuclearpowerplants, and military bases to renderpotential interference as small as possible. Inaddition, equipment would have to be rede-signed to permit far better rejection of un-wanted signals than is now necessary. This ap-pears to be feasible given enough time andfunds for the electronics industry to respond.

Effect on Terrestrial Astronomyand Aeronomy

None of the proposed SPS systems benefitastronomical research except insofar as theywould indirectly provide a transportationsystem and construction capabilities for plac-ing large astronomical facilities in space. Thedetrimental effects would vary depending onthe system chosen. The impacts of a micro-wave system are likely to be severe for bothoptical and radio astronomy. An infrared lasersystem is likely to have fewer detrimental ef-fects on both forms of astronomy, and the mir-ror system would have its most serious effecton optical astronomy.

Optical Astronomy.– Diffuse reflectionsfrom the reference system satellites wouldcause each to be as bright as the brightestphase of the planet Venus, and produce a dif-fuse halo of light around it. Because thesatellites appear to remain stationary alongthe celestial Equator, a system of 15 to 60satellites would meld together to block obser-vation of very faint objects along and near theEquator for telescopes located on Earth be-tween the longitude limits of the satellites (fig.7). Some major non-U. S. telescopes would beaffected as well. Telescopes in orbit, such asthe U.S. Space Telescope scheduled to belaunched in 1984, will travel in nonequatorialorbits and therefore would not be affectedsignificantly by a reference SPS except torequire increased pointing and control com-plexity on the Space Telescope.

The effect of diffuse reflections from anLEO-based laser SPS could be expected to bemuch less of a problem for observations of ob-jects near the Equator because the laser por-tion of the satellite system would be constant-ly in motion. Thus, no part of the sky would bepermanently blocked from view. The relaysatellites located in geostationary orbit wouldsubtend a very small angle as seen from thesurface of the Earth. Though they would bevisible as small points of light, they would beconsiderably fainter than the geostationary


Figure 7.—The SPS Brightness Profile

– 4 0 ° –20° 0° 200 40“ 60“ 80“

Declination

Note: This figure shows the predicted brightness of the sky as a result of a60-satellite SPS system along the meridian at local midnight for Kitt PeakNational Observatory at the vernal equinox. The calculation of this profileis based on an assumed 4 percent diffuse albedo

SOURCE: Workshop on SPS Effects on Optical and Radio Astronomy,DOE/Conf 7905143, P. A. Ekstron and G M Stokes (eds.).

satellites of the reference system and wouldnot interfere with optical observations. How-ever, large moving satellites would present op-tical astronomy with another observationalobstacle. Scattered Iight from them would varyin intensity as the satellite passes near acelestial object of interest, making calibrationof the nearby background light very difficult.The laser satellite would interfere with infraredastronomy studies involving wavelengths nearthe transmission wavelength of the beam. Pho-tometry and spectrometry experiments wouldbe severely compromised during any brief or-bital period when the relay satellite passedwithin a few degrees of an observing tele-scope.

The mirror system, which would involve anumber of large, highly reflective moving mir-rors in low Earth orbit, would have very seriouseffects on optical astronomy. While theprecise effect has not been calculated, itwould render a large area (a circle of radius150 km) around the ground stations unaccept-able for telescopic viewing. Because of diffusereflections from the atmospheric dust andaerosols that are up to 3 km above the groundstation, the individual mirrors would create

moving patches of diffuse light that wouldcompletely disrupt the observation of faint ob-jects that lie in the direction of the satellitepaths. Thus, astronomers would need to re-main outside a 30()-km diameter circle sur-rounding the site in order to avoid thisproblem.

Radio Astronomy. – Radio astronomy wouldsuffer two major adverse affects from micro-wave systems: 1 ) electromagnetic interferencefrom the main SPS beam, from harmonics,from scattered or reflected SPS signals, andfrom reradiated energy from rectennas; and 2)additional sources of thermal noise radiationin the sky that have the effect of lowering thesignal-to-noise ratio of the radio receivers.Studies by terrestrial radiotelescopes of faintradio objects near the Equator would be im-possible. Neither the laser nor the mirrorsystems would contribute to the first effect;however, they would raise the effectivetemperature of the sky background. Low-levelmeasurements such as scientists now routinelyconduct to measure the amount of back-ground radiation from the primordial explo-sion of the universe would thus be impossiblefrom terrestrial bases. Thermal microwaveradiation from the satellites would exceedpresent standards for radio interference atnearly all wavelengths.

Space basing of radio telescopes, especiallyon the far side of the Moon, would eliminatethe impact of SPS and other terrestrial sourcesof electromagnetic interference. However,such proposals, though attractive from thestandpoint of potential interference, areunlikely to be attractive to astronomers formany decades because of their high cost andthe relative inaccessibility of the equipment.

Optical Aeronomy. –Much of our knowledgeof the upper atmosphere is gained by night-time observations of faint, diffuse light. Someof the observations that are made today mustbe carried out in the dark of the Moon. Thepresence of satellites equal in brightness to aquarter Moon would effectively end somestudies of the faint airglow and aurora. Otherobservations would be severely limited inscope.

52 . SoLar Power Satellites

SPACE PROGRAM

How would development of the SPS affectour civilian space program?*

If pursued, an SPS program would be thelargest and most ambitious space programever undertaken. SPS development could pro-vide: 1 ) new capabilities for future space ven-tures; 2) spinoffs for civilian and military use,in space as well as other areas; 3) a politicaland programmatic focus for the civilian spaceprogram; and 4) potential furtherance of U.S.domestic and foreign policy goals.

An SPS program would require the develop-ment of a high-capacity space transportationsystem, the construction of large space struc-tures, and perhaps the deployment of mannedspace bases. I n addition, an extensive indus-trial infrastructure would be needed to supportthese activities. The hardware, knowledge, andfacilities generated by such a program wouldsignificantly increase our overall space capa-bilities and lay the groundwork for future in-dustrialization, mining and, perhaps, the col-onization of space.

Direct technological spinoffs can be ex-pected in the development of improved largespace platforms, energy transmission devices,ground illuminating systems, high-efficiencysolar celIs, and Iife-support systems.

Conversely, SPS development will benefitfrom prior developments in space technology,most notably in space transportation andsystems for automated construction of spacestructures.

An important consideration is the extent towhich an SPS program wouId serve as thefocus and driving-force for the space programas a whole. In the 1960’s, the U.S. civilian ef-fort was centered on Apollo; in the 1970’s onthe Space Shuttle. However, in 1978, the Carter

*For extended discussion see ch. 6

administration stated that: “it is neither feasi-ble nor necessary at this time to commit theUnited States to a high-challenge space engi-neering initiative comparable to Apollo. ” Inthe absence of a long-term goal such as SPS,some have predicted that future space effortswouId lag, or become overwhelmingly militaryin nature. On the other hand, there is concernthat an SPS commitment would draw re-sources from or otherwise interfere with otherspace activities, leading to an unbalanced ef-fort. In addition, for SPS as well as other lessexpensive programs, the annual appropriationsprocedure for NASA often results in budgetaryand programmatic uncertainty; developmentof SPS would require long-term financial plan-ning and long-term commitment to the project.

In addition to its use as a source of electricalpower, the SPS should be judged by whether itis in accord with national interests as reflectedin national space policy. The NASA Act of1958 (as amended), states that space activitiesshould be for peaceful purposes, and can beundertaken in cooperation with other coun-tries, to further the “general welfare andsecurity” of the United States. In 1978 theCarter administration, in its October “FactSheet on U.S. Civil Space Policy,” reaffirmedthese goals while emphasizing the practicaland commercial benefits of the civil space pro-gram. A civilian-run SPS program open to inter-national participation would further currentspace policy goals.

Involvement by NASA in SPS operationmight require a change of NASA’s currentcharter, which restricts the direct operation ofcommercial ventures. Currently, DOE hasprime responsibility for solar energy research,while NASA is responsible for the U.S. civilianspace program. An SPS program would requireextensive cooperation between the two agen-cies; if this caused difficulties, a separateagency or some other organizational alter-native might prove preferable.

Chapter 4

POLICY OPTIONS

Chapter 4

POLICY OPTIONS

Because the solar power satellite (SPS) is anew energy concept, much of this assessmenthas Ied across previously uncharted territory.SPS has potential for supplying a portion ofU.S. electrical needs, but current knowledgeabout SPS, whether technical, environmental,or sociopolitical is still too tentative or uncer-tain to decide whether SPS would be a wise in-vestment of the Nation’s resources. Furtherresearch and study, based on the findings ofthis and other assessments, ’ 2 would be neededin order to formulate such a decision properly.The kind and pace of a research program, ifone is to be conducted, will be determined byperceptions of when development decisionsneed to be made.

Decisions about SPS development involvean important tradeoff. I n time, more can belearned about the context within which SPSwould operate. Furthermore, in view of thisstudy’s analysis of future U.S. electricity de-mand and the availability of alternate energysources (see ch. 6), domestic need is not likelyto be high enough for SPS before 2015-25.Therefore, development and deployment deci-sions do not have to be made before the1990’s. However, action should be taken in atimely manner. Since the development of amajor energy and space system may take morethan 20 years, a decision about whether todevelop SPS will probably need to be madebefore the end of the century. The develop-ment of SPS may need to be started as early as1990, if high-growth projections for electricityseem plausible at the time. If an SPS develop-ment program is eventually initiated, the Na-tion must also decide whether it wishes to pur-sue SPS as a unilateral or as an internationalventure. The tasks before the United States inthis decade are to determine how much andwhat kinds of information are needed in orderto make a sound decision sometime in the next

‘Program Assessment Report Statement of Findings, SPS C o n -cept Development and Evaluation Program, DO E/E R-0085,November 1980.

‘National Research Council Report of the Committee on Satel-lite Power Systems, June 1981

decade. The Nation must also decide when toproceed with a research program and at whatpace.

Figure 8 represents a series of possible deci-sion points for SPS. If research on SPS finds noimpediments to continued pursuit of SPS, thefirst in the series of development decisionscouId occur sometime between 1990 and 2000.By that time, the factors that relate to energydemand and supply and space transportationwill be much clearer than they are today. TheUnited States will have had about 10 years ofexperience with the space shuttle and with ini-tial testing of space platform components.Planning and perhaps testing will have begunfor a second-generation space transportationsystem. The resuIts of the Nation’s long-termenergy conservation efforts will be felt andassessed, and electricity demand projectionsfor 2000 and afterwards will be better definedthan currently possible. Further, a decisionabout the breeder may have been made andthe potential of the fusion, energy storage, andterrestrial solar technologies may be more cer-tain.

The results of continued tracking of the in-ternational, institutional, and public opinionfactors relevant to SPS will also contribute tothe decision. In particular, the internationalcommunity’s future energy needs and supplypotential will be better known, as well as itswillingness to cooperate in a multinationaldevelopment program.

Finally, the results of research related to SPSwilI be available and can be used to support orreject a decision whether to proceed with SPSdevelopment. Some of the needed research isgeneric in nature, and will be done in otherprograms whether or not SPS is developed.Among others, these include most of the Na-tional Aeronautics and Space Administration’s(NASA) activities in space transportation,space structures, photovoltaics, materials andhumans in space, as well as the Department ofDefense’s (DOD) and the Department ofEnergy’s (DOE) laser programs. To some extent

55


Figure 8.—SPS Program Phases and Decision Points

Program level(funding)

Demonstration

Systemsengineering,space testing

Research,componenttesting

CDEP

No program

. . . . . .

DP 1 DP 2 DP 3 DP 4 Time

● DP 1 ● DP 2 ● DP 3 ● DP 4— No program —— Research —

.


they also include work done in the

No program — No program —Research — Research —Initiate development — Cont inue systems —

engineering— Demonstration —

—

No SPSResearchSystemsengineeringNew demonstrationDeployment

terrestrial eventually require a research program spe-photovoltaics (DOE) and microwave bioeffects cifically funded for SPS.(the Food and Drug Administration, the En-vironmental Protection Agency, etc.) pro- In order to make an informed decision aboutgrams. However, many needs are directly the SPS, information about three differentrelated to SPS technology and therefore will types of factors will be needed:

Ch. 4—Policy Options ● 57

1. Contextual, independent factors. Theseare factors that are independent of SPSbut which will markedly affect the needfor SPS or the ability to conduct the proj-ect:● Future U.S. and global electricity de-

mand. If demand is relatively low, theneed for a new, capital-intensive energysystem will be low as well. If future de-mand is very high, there could be acommensurate need for SPS. Conserva-tion, increased end-use efficiencies, andthe expansion of dispersed electricalgeneration could all affect overall de-mand for centralized electricity.

● Cost, kind, and availability of alter-native electricity sources. If other po-tential future electric energy sourcesturn out to be more expensive than aprojected SPS, then SPS may be desira-ble even if electricity demand is rela-tively low. On the other hand, the devel-opment of other technologies mightpreclude the need for SPS. The status ofbreeder and fusion technologies, thecost of terrestrial solar and the ad-visability of expanding the use of coalwill all affect the need for SPS.

● U.S. and global space capabilities. Arapidly expanding space program withextensive experience and capabilitieswould make an SPS program muchmore feasible than would a low-levelprogram. The experience with the shut-tle and other space vehicles will shedlight on space transportation capabili-ties and costs.

Although an SPS research program is notlikely to be affected by these factors, they willhave a great effect on an SPS developmentdecision. Each of the factors needs to betracked, studied, and continually reevaluatedfor its impact on an SPS decision. Projectionsof these factors 10 to 20 years in the future willhave to be made as well, and amended as moreinformation becomes available. Because thesefactors are of universal interest, such studiesneed not be funded by a specific SPS program;they will be investigated by other energy andspace programs.

Sometime in the next decade, the contextualframework for the future of SPS may be knownwell enough to make an informed decisionabout the need for SPS. As time goes on, a nar-rowing of future projections will occur andknowledge of these factors will be integratedinto the overall decision about SPS.

2. Contextual, semi-independent factors.These are the factors that arise largelyfrom the public perceptions and interna-tional and institutional framework of SPS.Though they are markedly diverse in con-tent, they have the unifying feature thatthey will each affect an SPS research pro-gram only slightly but an SPS develop-ment program rather strongly. They willneed to be tracked, studied, and evalu-ated as any SPS research program pro-gresses. They also possess the character-istic that there is no point at which onecan say that enough is known about them.Rather, a development decision must takethem into account as factors that must beconsidered in Iight of what is known aboutthem at the time.●

●

International interest and involvementin SPS. The worldwide community willbe interested in SPS for its potential toprovide energy. They will also be con-cerned about the effects it may have onthe use of the geostationary orbit, mili-tary and national prestige implications,how it may affect communications, andhow it may affect the appearance anduse of the night sky. They may also beinterested in joining with the UnitedStates in multinational development ofSPS. Hence, it will also be important toexplore possible modes and means ofinternational cooperation.

Institutional framework. A main con-cern of any SPS program would be tocontinue to study the institutionalstructures that now exist in the utilitiesindustry, the financial community, andGovernment, and to identify the majorfactors that could influence the courseof SPS development and affect itsfeasibility.

83-316 0 - 81 - 5


● Public opinion issues Public percep-tions and public involvement are im-portant components of any publiclyfunded program. Dissemination of in-formation and sharing of researchresults would be essential to the SPSprogram, even in the research phase. Itwould also be important to continue tosolicit responses from segments of thepublic that would be especially af-fected, either positively or negatively,by SPS development.

3.Technical factors specific to SPS. Knowl-edge about these factors can be gatheredor generated by deliberate effort. Answersto specific questions in this group willhave an immediate effect on SPS develop-ment decisions. The kind, quantity, andquality of the information as well as thetime at which it can be available are part-ly dependent on the level of funding. Fourgeneral categories of this sort of informa-tion are evident:● Environment and human health:

— microwave and laser bioeffects,–high energy particle and ionizing ra-

diation effects on humans in space,— ionospheric effects due to micro-

wave transmission,– land-use impacts,—offshore rectenna environmental ef-

fects,– launch vehicle exhaust effects on at-

mosphere, and—weather modification from mirror

systems.● General system studies:

—alternate systems (identify whichareas need further research, and pos-sible testing of components),

— component and system costs, and—comparison of alternate systems.

● Component testing and evacuation:–Klystrons/magnetrons/solid-state de-

vices,– high-powered, continuous-wave la-

sers (EDL, solar pumped, FE L),— SIip ring designs,–deployable, large-area, lightweight

space structures,

— space charge effects, and– photovoltaic design and testing.

● Space construction and space transpor-tation:— evaluate best transportation scheme

for demonstration and— evaluate best construction scheme.

information from all three sorts of factorswill set the framework and determine the ap-propriate time for development decisions. It isimportant to emphasize that a decision not todevelop SPS depends on the same informationas a decision to proceed with SPS. If furtherresearch finds no major technological impedi-ment to proceeding with SPS and the combina-tion of supply alternatives and demand needsindicate that it would be prudent to proceedwith the next stage, the program could enterthe engineering verification phase where var-ious systems are tested and a demonstrationsystem chosen. This would set the stage for thenext decision point.

[f it were possible to make a decision to pro-ceed with the project early in the process (i. e.,during the research phase) the various phasescould overlap considerably. For instance, theearly stages of demonstration could beginbefore the engineering verification phase isentirely complete. Some economic benefitsmight accrue from such a procedure. However,because of the very high front-end costs forSPS, any proposal to proceed with develop-ment will need to be scrutinized very carefullyto be sure it is cost effective. That willnecessitate more time and study in the veri-fication stage than might be true for a lesscostly technology, making it less likely that thevarious phases will overlap.

SPS research could proceed at differentrates and along different lines, depending onthe level of funding that is made available. Thefollowing presents two different policy op-tions. One is characterized by zero funding forspecific SPS research; the other by a slidingscale of funding. They do not exclude oneanother, i.e., pursuing one option today wouldnot necessariIy exclude changing to a differentoption as time proceeds and information

Ch. 4—Policy Options ● 5 9

grows. For example, it could be consideredprudent to begin with no specific funding forSPS and proceed to allocate a few milliondollars per year after a few years. Conversely,a vigorous funding pace may produce resultsquickly enough so that from the standpoint ofthose factors that are amenable to research, adevelopment decision could be made before1990. But because the independent factors areunlikely to be known well enough before 199o,research funding might then be reduced to alower level to keep the program going pendinga decision based on the independent factors.

Option A:No specific funding for an SPS program.

Although it would be nearly impossible topursue an SPS program without specificallyallocating funding for it, this option would notnecessarily mean terminating all interest inSPS. A zero level option could be followed bydesignating an agency (e.g., NASA or DOE) totrack generic research that is applicable toSPS, as well as monitoring and coordinating in-ternational interest in SPS. One possibility is toset up a high-level advisory committee to servethis latter function. As in the other option,periodic reevaluation of the potential of SPSwould also be needed, in this case to decidewhether specific funding should be institutedor the program terminated altogether.

The rationale behind option A is to keep SPSalive as part of our arsenal of possible energysupply options without making a serious com-mitment at this time. It has the advantagesthat the risk of premature funding is greatlyreduced, as well as the upfront costs. Thelonger the country can wait before funding aprogram directed towards SPS research, themore likely it is that other programs will havegenerated helpful data for SPS.

On the other hand, there is little margin forerror in such an approach. If, under option A,inadequate information is generated, the SPSoption might be neglected or foreclosed at atime of future decision; or, if the independentfactors indicate a strong need for SPS, then anexpensive crash program of research to resolvethe questions specific to SPS may be neces-

sary. in addition, appropriating no specificfunding for SPS carries with it the risk ofdiscouraging future international cooperation,or of allowing other countries to take the leadin SPS development. A final problem with op-tion A is that the agency designated to trackSPS may find it very difficult to allocate itsfinancial resources for SPS without some spe-cific allocation in its budget (even thoughsmall).

What could be learned from such an option?Other Federal and non-Federal programs arecurrently exploring issues that are related toSPS development. By tracking this generic re-search, information of great value to the de-velopment decision could be gathered andanalyzed.

●

●

●

●

Microwave bioeffects.The proliferation ofmicrowave devices at various frequenciesmakes research into this important areamandatory whether there is an SPS programor not. FDA, EPA, and DOD are studyingmicrowave bioeffects.Photovoltaics DOE maintains a strong ter-restrial photovoltaics program. Togetherwith private industry and university projects,this program is studying some aspects ofphotovoltaics that are of great interest toSPS. However, because terrestrial photovol-taic systems have vastly different needs andconstraints than space photovoltaic sys-tems, additional research would probably beneeded for SPS.Space-related activities. NASA, DOD, andthe European Space Agency (ESA) are pursu-ing programs in space transportation, spacestructures, humans in space, and space pho-tovoltaics by designing and building theshuttle, advanced expendable launch vehi-cles, space lab, a 25 kW space power supply,etc.Laser programs. High-powered, continuous-wave lasers are currently in an early stage ofdevelopment. Some of the research on highenergy pulsed lasers being pursued by theDOD for weapons applications and by DOEfor fusion studies will be relevant to the SPSlaser concept. Universities and other re-search labs are studying high-powered, con-


tinuous-wave lasers. This research would bedirectly applicable to a laser SPS.

● Alternateve energy sources. The resuIts ofR&D, prototype construction, and operationof other electricity sources, including solarthermal, breeders, ocean thermal energyconversion, and fusion, will be of great im-portance in determining future need for SPS.

However, many issues directly pertinent toSPS cannot be answered by generic researchprograms. For instance, while microwave bio-effects experiments are being performed ingeneric research programs, the number ofstudies on low-level, long-term exposure to SPSfrequency microwaves is small.mation directly relevant to SPS,SPS funding will be needed.

Option B:Funding of $5 million to $30year.

To gain infor-some specific

million per

This option is designed to gather the neces-sary information before a development deci-sion is needed. It minimizes the risks of notgaining the sufficient and timely informationnecessary for a rational decision.

This program would, like option A, make asmuch use as possible of generic research. Itwould extend the generic research into areasspecific to SPS by making small amounts offunding available for expanding generic pro-grams essential to the SPS development deci-sion. It would also initiate research that is notbeing done in generic programs and exploreways in which to pursue some of this researchjointly with other nations. In addition, it wouldtrack and study the various semi-independentfactors (international, institutional, and publicopinion) which would also have a profound ef-fect on SPS decisions. It would actively seekand encourage international cooperation inSPS research.

Table 5 summarizes the most important re-search and study needs and gives a very roughestimate of what it would cost to do each item.The starred items are ones that could be pur-sued in the context of a few million dollars offunding per year. The most critical issues re-late to the environmental and health area,

since they are the most important in determin-ing the feasibility of SPS. However, they couldalso take the longest to resolve. Some compo-nent testing and studies of alternative systemscould receive high priority. The amount offunding which would be made available woulddepend on an evaluation of previous researchfindings and the state of projected supply anddemand for electricity in the 21st century.

It may be prudent to start at a low level offunding and later accelerate research that isspecific to SPS as well as make greater fundingavailable for SPS related generic studies.Another possibility is to actively solicit fund-ing for projects of joint international-U. S. in-terest, perhaps by offering to match foreignfunding for research projects undertaken out-side the United States, but which are of in-terest to U.S. planners. An accelerated re-search program ($30 million per year) could in-clude some component testing in space as welIas at the Earth’s surface. It could also includeat least one shuttle mission (post 1985) andsome space-related experiments on other shut-tle flights. It would seek to answer the majorenvironmental and health and safety questionsbefore 1990 and also conduct extensive sys-tems studies. If these concerns are seen to poseno impediments, accelerated funding wouldprovide the quickest way of entering a devel-opment phase.

Making funds available for SPS-specific re-search should ensure that enough informationis eventually available in order to make a ra-tional development decision. This approachalso has the advantage that it could providefor extensive international cooperation earlyin the research phase before seeking more ex-tensive financial and managerial cooperationin any subsequent development or construc-tion phase. This would spread the decision toproceed or drop SPS development to othercountries as well.

However, a higher level of spending ($30million or so per year), here and abroad, wouldmake it more likely that an entrenched SPSconstituency would form, giving the programmomentum and making it harder to stop; moreinformation may not make a program easier to

Ch. 4—Policy Options ● 61

terminate. Under such conditions, our under- transmitting power will develop too early andstanding of SPS technology may outstrip our close out SPS options which are uncertain inknowledge of future electricity demand. It is the near term but which may have more long-also possible that support for a given mode of run potential.

Table 5.—Summary of Research and Study Needs

Expansion of generic research Estimated EstimatedResearch/study area to SPS-specific needs cost SPS-dedicated projects costs

Environmental and human health—

● Microwave bioeffects $5 million to Quantify SPS risks. $2 million$10 million Epidemiological

studies.● Laboratory studies of long-termexposure to low-levelmicrowaves at 2.45 GHz.Determine possible nonthermaleffects, and dose-responserelationships, establishextrapolation laws.

● Ionospheric studies ● Study of ionospheric scaling —laws.

microwave

● Atmospheric studies ● Track and augment observa-tions of the atmosphericeffects of launch effluentsfrom the shuttle, other ex-pendable launch vehicles andhigh altitude rockets.

Refine and test groundcloud models. Studymeteorological and airquality impacts.

Determine the nature andeffect of ionospheric de-pletion, especially inlower ionosphere. Utilizeother rocket launches andobserve the effects onrepresentative telecom-munication systems.

● Ionizing radiation ● Track and augment existingstudies of effects of ionizingradiation on humans.Study shielding methods.

● Space ● Track and augment existingprograms examining the risksand protection measures forhumans in space.

● Electromagnetic ● Study potential electromag-interference netic interference and design

mitigating techniques. Improvetheory of phased array.

$2 million

$0.3 million to$5 million

$0.5 million

$2 million to$3 million

$0.2 million

$2 million

‘Ionospheric equivalent $10 millionheating. Upgrade Arecibofacility. Study SPSequivalent heating inupper atmosphere. Testscaling laws and effectson representative tele-communication systems.

● Experiments to test $1 millioneffects of SPSeffluents on mag-netosphere and toincrease understanding ofthat region.Quantify and study SPSeffects on the hydrogencycle, and formation ofnoctilucent clouds.

● Study effect on localclimate of SOLARES-typesystem using an array ofground heaters or a solarpond.

*Studies of possibleweather modification,beam scatteringand spreading.Identify transportationscenarios thatminimize impacts.

● Investigate antenna $1 millionpatterns of klystron,magnetron, solid-state devices (see below),their noise levels, andout-of-band harmonics.


Table 5.—Summary of Research and Study Needs—Continued

Expansion of generic research Estimated EstimatedResearch/study area to SPS-specific needs cost SPS-dedicated projects costs

• Environmental Offshore receiver studies $0.5 millionimpacts of Land use studies $2 millionreceiver siting

General system studies● Laser system

● Mirror system

● Alternative microwave

Component testing andevaluation

● Microwavetransmission

● Continue solid-state device $3 million toimprovement, study noise, $6 millioninterference problems

● Test intermediate power $2 millionmagnetron, high-power klystron

● Solar thermalconversion

. Photovoltaics ● Extend research to low mass,thin film cells for space

● Lasers ● Improve efficiency of EDLlasers, develop cooling mech-anisms for space lasers

. Mechanicalcomponents

● M i r r o r

$1 million

$2 million

$3million to$10 million

● Develop a “reference” $0.5 million tolaser system $1 million

*Develop a “reference” $0.5 million tomirror system $1 million

*Develop alternativemicrowave systems

*Perform a true compar- $1 millionative study between SPSalternatives using com-mon technology and costbasis.

Develop solid-state $2 million tophased array $10 millionStudy alternative micro- $.3 million towave devices, such as $1 millionphotoklystron

● Adapt optimum $2 millionphotovoltaics for SPS,i.e., low mass, highefficiency, radiationresistant

● Build solar pumped $1 million tolasers $3 million

● Laser optics $0.1 million to(feasibility studies) $0.3 million

● Study means of $0.3 millionconstructing slip ringand rotating joint

*SOLARES mirror materialsstructuresDevelop prototype mirror $0.5 milliondesign for shuttle launchof a single SOLARESmirror

‘Research priority.


Chapter 5ALTERNATIVE SYSTEMS FOR SPS

ContentsPage

Microwave Transmission . . . . . . . . . . . . . . 65The Reference System.. . . . . . . . . . . . . 65

Laser Transmission.. . . . . . . . . . . . . . . . . 78Laser Generators . . . . . . . . . . . . . . . . . . . 79Laser Transmission . . . . . . . . . . . . . . . . 81Laser-Power Conversion at Earth . . . . . . 82The Laser-Based System . . . . . . . . . . . . . 82

Mirror Reflection . . . . . . . . . . . . . . . . . 86The Mirror System. . . . . . . . . . . . . . . . . . 88

Space Transportation and ConstructionAlternatives . . . . . . . . . . . . . . . . . . . 89

Transportation . . . . . . . . . . . . . , . . . . 89Space Construction. . . . . . . . . . . . . . . . . 91

SPA Costs . . . . . . . . . . . . . . . . . . . . . . . . . . 92Reference System Costs . . . . . . . . . . . . 92

Alternative Systems . . . . . . . . . . . . . . . . 96The Solid-StateSystem . . . . . . . . . . . 96The Laser System . . . . . . . . . . . . . . . . . . 96The Mirror System. . . . . . . . . . . . . . . . . 97

LIST OF TABLES

Table No. Page

6.

7.8.9.

10.11.12.13.

Projections for Laser Energy Convertersin 1981-90 . . . . . . . . . . . . . . . . . . . . . . .500 MWe Space Laser Power System. . .Laser Power Station Specification. . . . .SOLARES Baseline Systerm . . . . . . . .Research— $370 Million . . . . . . . . . .Engineering– $8 Billion . . . . . . . . . . . .Demonstration– $23 Billion . . . . . . .SPS lnvestment– $57.9 Billion . . . . . . .

8385858893939394

LIST OF FIGURES

Figure No. Page

9

10

11

1213

14

1516

17

18

1 9

20.2122.23.2425

26

Solar Power Satellite ReferenceSystem. . . . . . . . . . . . . . . . . . . . . . . . . . 66Satellite Power System EfficiencyChain . . . . . . . . . . . . . . . . . . . . . . . . . . . 67Major Reference System ProgramElements. . . . . . . . . . . . . . . . . . . . . . . . 68The Retrodirective Concept . . . . . . . . . 69Power Density at Rectenna as aFunction of Distance From theBeam Centerline . . . . . . . . . . . . . . . . . . 70Peak Power Density Levels as aFunction of Range From Rectenna . . . . 70SPS Space Transportation Scenario . . . 73The Solid-State Variant of the ReferenceSystem. . . . . . . . . . . . . . . . . . . .lndirect Optically Pumped CO/CO2

Mixing Laser . . . . . . . . . . . . . . . . .The CATALAC Free Electron LaserConcepts. . . . . . . . . . . . . . . . . . . . .Optics and Beam Characteristics ofTwo Types of Laser Power Trans-mission System (LTPS) Concepts. . .The Laser Concept. . . . . . . , . . . . .Components of the Laser Concept .The Mirror Concept (SOLARES) . . .Reference System Costs . . . . . . . . .How Cost Could Be Allowed. . . . . .Elements and Costs, in 1977 Dollars,the Baseline SOLARES System . . . .Sensitivity of the SOLARES MirrorSystem to Variations in SystemParameters . . . . . . . . . . . . . . . . . . .

. . . 78

. . . 80

. . . 81

. . . 82

. . . 84

. . . 84

. . . 87

. . . 9293

for. . . 97

. . . 98

Chapter 5

ALTERNATIVE SYSTEMS FOR SPS

A variety of systems have been proposed forcollecting, transmitting, and converting solarpower from space. Each system has its advan-tages and disadvantages, its benefits and draw-backs. Each alternative system would use oneof three transmission modes — microwave,laser, or optical reflector–to transmit powerto Earth where it is collected and converted toelectricity or some other highly useful form ofenergy. Each system would use numerous sub-systems to collect and convert energy in spaceor on the ground. This chapter wiII character-ize the alternative systems and subsystems anddiscuss their potential for generating powerfrom space. It will also describe four repre-sentative systems that serve as the technicalbasis for discussion of the environmental, insti-

tutional, and public acceptance issues in thechapters that follow.

In order to estimate reliably and fully therange of costs and potential technical uncer-tainties for a given solar power satellite (SPS)option, it would be necessary to subject it tothe same detailed analysis that the referencesystem has undergone during the last 5 years.Unfortunately, this analysis has not been ac-complished for the alternative systems. Hence,detailed comparisons between systems will notbe possible. At this stage it is possible only tocompare the major features of each technol-ogy and note the uncertainties that should beaddressed as conceptual development of thevarious alternatives continues.

MICROWAVE TRANSMISSION

Because the atmosphere is highly transpar-ent to microwaves, they constitute an obviouscandidate for the SPS transmission mode. Inaddition, microwave technology also is well-known and is used today in a number of spaceand terrestrial communications and radar ap-plications. Microwave power transmission wasfirst demonstrated experimentally in 1964, ’and tested in 1974.2 3

The Reference System4 56

The reference system was selected by theDepartment of Energy/National Aeronautics

1). F Degenford, M D. Sirkis, and PV H Steir, “Ttle ReflectingBeam Waveguide, ” I E EE Transact ions 01 Microwave Theory

Technology MIT-72, July 1964, pp 445-453‘Richard M Dickinson, “Evaluation of a Microwave High-

Power Reception-Conversion Array for Wireless Power Transmis-sion, ” Jet Propulsion Laboratory Technical Memorandum No33-741, Sept 1, 1975

~R i chard M Dick InsOn, “Microwave Power TransmittingPhased Array Antenna Research Project Summary Report, ” JetPropulsion Laboratory publication No 78-28, Dec 15, 1978

‘Department of Energy, “Satellite Power System Concept De-velopment and Evaluation Program Reference System Report, ”report No. DOE/E R-0023, October 1978

‘C. C. Kraft, “The Solar Power Satellite Concept, ” NASA pub-lication No JSC-14898, July 1979

and Space Administrationbasis for study. It consists

(DOE/NASA) as aof a large planar

array of photovoltaic celIs located in the geo-synchronous orbit 35,800 km above the Earth’sEquator (fig. 9). The cells convert solar energyinto direct-current (de) electricity that isconducted at high voltage to a phased-arraymicrowave transmitting antenna mounted atone end of the photovoltaic array. Klystronamplifiers convert the dc electricity to high-voltage radio-frequency power that is thenradiated to Earth by slotted waveguides. Areceiving antenna (rectenna) on the groundreconverts the electromagnetic radiation intoelectric current and rectifies it into dc. Afterbeing converted to high-voltage, low alter-nating current (ac), the power can then beeither delivered directly to the conventional acgrid or converted back to dc at high voltageand delivered to a dc transmission network.

The amount of power delivered to the gridby each reference system rectenna has been

bR O Piiand, “SPS Cost Methodology and Sensitivities, ” TheF/na/ Proceedings of the Solar Power Sate l l i te Program Review,

DOE/NASA Conf-800491, July 1980.

65


Figure 9.—Solar Power Satellite Reference System

Transmitt

Solar power satellite reference system

Solar cell arr

ty

SOURCE: C. C. Kraft, “The Solar Power Satellite Concept,” NASA publication No. JSC-14898, July 1979

set at 5 gigawatts (GW)—or 5,000 megawatts(MW). The microwave transmission frequencywas chosen to be 2.45 gigahertz (GHz). Max-imum microwave power density at the centerof the rectenna (on Earth) was set at 23milliwatts per square centimeter (mW/cm 2),and the maximum power density at the edge ofthe rectenna was set at 1 mW/cm 2 (one-tenththe current U.S. recommended occupationallimit). The reference design assumes that allmaterials would be obtained from Earth, andthat the system lifetime would be 30 years withno residual salvage value.

The area of the satellite’s photovoltaic arraywould be approximately 55 square kilometers(km 2); the diameter of the transmitting antenna1 km. The total in-orbit mass of the completesystem, including a 25-percent contingencyfactor, would be either 51,000 or 34,000 metrictons (tonnes), depending on whether silicon orgallium arsenide photovoltaic cells would beused.

The system is designed to deliver baseload,i.e., continuous 24-hour power to the electricgrid. However, some variations in deliveredpower would occur. A seasonal fluctuation inoutput due to the variation of the Sun’s dis-tance from Earth would cause variations inboth incident insolation and photovoltaic celltemperature, the latter producing a conse-quent change in efficiency. In addition, aroundthe spring and fall equinoxes the Earth’sshadow would occult the SPS, resulting in ashort period each night for about 6 weeks atlocal midnight (about 75 minutes maximum, atthe equinoxes) where no solar radiation im-pinges on the satellite and therefore no powercould be delivered to the grid (see ch. 9 for adiscussion of this effect).

Subsystem Description

ENERGY COLLECTION AND CONVERSIONTwo photovoltaic concepts were considered

for the DOE/NASA reference system. One uses

Ch. 5—Alternative Systems for SPS . 67

Ga71.77 GW(Solar)

70.81 GWSi

Figure 10.

63.18 GW

62.34 GW

-Satellite Power System Efficiency Chain

57.81 GW 11.58 GW 10.50 GW 9.46 GW

Ga

10.79 GW 10.29 GW 9.79 GW

Si

Ga 9.08 GW8.50 GW 8.50 GW 8.18 GW 6.96 GW 6.72 GW

Si

9.08 GW

6.58 GW 5.79 GW 5.15 GW

overall efficiency = 6.970/. Ga MPTS efficiency = 63.00/.7.06% Si

Abbreviation: “Ga” indicates the gallium-alum aluminum-arsenide option, “Si” the silicon option.

SOURCE: Department of Energy, “Satellite Power System Concept Development and Evaluation Program: Reference System Report,” DOE report No.DOE/ER-0023, October 1978.

single crystal silicon converters that wouldreceive sunlight directly; the other usesgallium-arsenide (GaAs) photovoltaic cells il-luminated directly and by mirrors in a 2:1 con-centration ratio.

Silicon cells, currently used in all solarpowered spacecraft, have the advantages ofan extensive manufacturing base, abundant re-source materials, and lower cost per cell, aswell as an R&D program in DOE aimed at ma-jor cost reduction for terrestrial cells. How-ever, silicon cells in space suffer degradationfrom radiation effects and from high-operatingtemperatures, and hence would probably re-quire periodic annealing of the array surface(possibly by laser or electron beam techniques)or the development of silicon cells less af-fected by ionizing radiation.

Gallium-aluminum arsenide photovoltaiccells have several advantages over silicon

cells: low mass per unit area, resistance to ther-mal and radiation degradation, and higher effi-ciency. They have the disadvantages of rela-tively high cost, the limited production availa-bility of gallium, and a smaller technologybase than for silicon cells. Because of theselatter characteristics, these cells would beused in a 2:1 concentration ratio in the refer-ence system, trading the relatively expensivecells for less expensive Iightweight reflectorsto concentrate sunlight on the cells.

The structure that supports the solar cellswould be an open-truss framework made ofgraphite-fiber reinforced thermoplastic com-posite (fig. 9). Because the solar array must beoriented toward the Sun and the transmittingantenna toward the Earth, a massive rotaryjoint is essential in order to provide the nec-essary mechanical coupling. Sliprings about400 m in diameter would be used in conjunc-


Figure 11 .—Major Reference System Program Elements

constructiondepot

Spacefreighter

COTV

GEO

SOURCE: R. O. Piland, Cost Methodology and Sensitivities,” The Final Proceedings of the Solar Power Satellite ProgramReview, DOE/NASA 1980.

tion with the rotary joint in order to transferelectric power from the array to the antenna.

POWER TRANSMISSION AND DELlVERYThe power transmission and delivery system

for the reference system design is common toboth photovoltaic options. It is composed ofthree major elements: the transmitting anten-na, the rectenna, and the substation.

The selection of the microwave transmissionfrequency was based on tradeoffs between at-mospheric attenuation and interactions withthe ionosphere as well as the sizes of theantenna and rectenna. The optimal frequen-cies were found to be between 1.5 and 4 GHz.The reference frequency was selected to be2.45 GHz, which lies in the center of the inter-national Industrial, Scientific, and Medical(ISM) band of 2.4 to 2.5 GHz.

The size of the antenna is determined by thetransmission frequency, the amount of heat itis feasible to dissipate at the antenna, thetheoretical limits of ionospheric heating, andthe maximum power densities chosen atground level, i.e., at the rectenna. 7 For the

‘Raytheon Corp., “Microwave Power Transmission SystemStudies,” report No, ER75-4368, contract No NAS3-I 7835, De-cember 1975.

reference system, these design considerationsresulted in a l-km diameter antenna. It wouldbe constructed of 7,220 subarrays each con-taining from four to thirty-six 70-kW klystronpower amplifiers connected to slotted wave-guides for transmitting power to Earth. KIys-trons were chosen because their technologyand operating characteristics at low powerlevels are well-known. However, they require acooling system (probably heat pipes). Klystronsof 70-kW continuous power rating have notbeen built and tested at this frequency, so theircharacteristics are not known in detail.

Each of the more than 100,000 klystrons inthe antenna must be properly adjusted or“phased” to provide a uniform power beamand to point it. This adjustment is especiallycritical at the very high, gross power level ofthe SPS beam. Were the antenna a totally rigidarray of amplifiers precisely fixed in space, theadjustment could be accomplished once andfor all just after the antenna is fabricated inspace. However, because it would be desirablefor the antenna to be relatively flexible itwould be necessary to use an active system ofphase control, a so-called “adaptive electroniccontrol” in which a pilot beam, installed in thecenter of the rectenna and pointed toward the

Ch. 5—Alternative Systems for SPS ● 69

satellite, establishes a phase reference orstandard clock against which the individualklystrons compare and adjust their phases (fig.12).8

An important safety feature inherent in thissystem is that loss of the pilot beam from therectenna would eliminate all pointing andphase control. Without the pilot beam, theklystron subarrays would immediately losesynchronization with one another and al I focuswould be lost, resulting in the spreading of the

‘William C Brown, “Solar Power Satellites Microwaves Deliv-er the Power, ” Spectrum, June 1979, pp 36-42.

Figure 12.—The Retrodirective Concept

In the retrodirective-array concept, a pilot beam from thecenter of the rectenna establishes a phase front at thetransmitting antenna. Central logic elements in each of theantenna’s 7,220 subarrays compare the pilot beam’s phasefront with an internal reference, or clock phase. The phasedifference is conjugated and used as a reference to controlthe phase of the outgoing signal. This concept enables thetransmitted beam to be centered precisely on the rectennaand to have a high degree of phase uniformity. If this phase-control system fails, the beam would automatically bedefocused, dropping the power density to 0.003 mW/cm2,an intensity acceptable by current standards. This featurehas been referred to as the “fail-safe” aspect of themicrowave transmission system.

SOURCE: William C. Brown, “Solar Power Satellites: Microwaves Deliver thePower,” Spectrum, June 1979, pp. 36-42.

beam to very low power (0.003 mW/cm 2). Thetransmission system would therefore requirecontinual ground-based guidance to keep itoperating as a coherent beam. By incor-porating relatively well-known anti jammingtechniques in the pilot-beam generator, de-liberate or accidental diversion or misuse ofthe SPS beam could be prevented.

The parameters of the microwave beam areof critical importance in assessing the en-vironmental impacts of the SPS. The peakpower density at the transmitting antenna iscalculated to be 21 kW/m2. By the time thebeam reached the upper atmosphere it wouldhave spread considerably and the intensityreduced to 23 mW/cm 2, a power Iimit that wasset because theoretical studies suggested thatat higher power densities, nonlinear instabil-ities could appear in the F layer of the iono-sphere (200 to 300 km) as a result of the inter-actions between the beam and the electricallycharged particles in this region. Recent ex-perimental studies indicate that the limit in thelower ionosphere might be able to be set muchhigher, ’ thereby making it possible to decreasethe size of the antenna and/or rectenna signifi-cantIy.

With these design constraints, a theoreticalbeam power distribution was conceived result-ing in the radiation pattern at the rectennashown in figure 13, on which are noted thepresent U.S. recommendations for public ex-posure (10 mW/cm 2) and the current U.S.S.R.occupational guideline (0.01 mW/cm 2).

The off-center peaks in figure 13 are called“sidelobes;” the level of intensity shown is aconsequence of the 1-km antenna aperture(which is optimized to minimize orbital mass)and the projected cumulative antenna errors.The first sidelobe would have a peak intensityof 0.08 mW/cm 2, less than one-hundredth thecurrent U.S. occupational exposure recom-mendation, about 8 km from the beam center-line; the intensity at the edge of the referencesystem rectenna (5 km from the beam center-line) would be 1 mW/cm 2–one-tenth the U.S.occupational exposure guideline.

‘w Cordon, and L M Duncan, Impacts on the UpperAtmosphere,” Astronautics and Aeronautics, July/August 1 9 8 0


10

5

1.0

0.01

0.005

0.001

USA standard

0 5,000 10,000 15,000 20,000

Ground radius, m

SOURCE: Department of Energy, “Satellite Power System Concept Develop-ment and Evaluation Program: Reference System Report,” DOEreport No. DOE/ER-0023, October 1978.

In addition to the relatively strong sidelobes,the finite size of the antenna subarrays andtheir projected misalinements would producemuch weaker “grating lobes, ” which for thereference system would occur at 440-km inter-vals from the rectenna. The integrated intensi-ty of these grating lobes, even for hundreds ofoperational SPSs, would be well below eventhe U.S.S.R. public-exposure guideline, asshown in figure 14.

Figure 14.—Peak Power Density Levels as aFunction of Range From Rectenna

10

10

10

o 2,000 4,000 6,000 8,000

Radius from boresight (km)

I I I I I I 1 I I 1 I Io 1,000 2,000 3,000 4,000 5,000

Radius from boresight (miles)

Grating lobe spikes occur every 245 km for the 18-m sub-arrays used on simulations although only two grating lobesare shown. The SPS 10-m subarrays have grating lobesevery 440 km.

SOURCE: Department of Energy, “Satellite Power System Concept Develop-ment and Evaluation Program: Reference System Report,” DOEreport No. DOE/ER-0023, October 1978.

The rectenna design is quite insensitive bothto the angular incidence of the microwavebeam (within 100, and to variations in phase oramplitude caused by the atmosphere. Hence,rectennas would be interchangeable; the samesatellite could power different rectennas, aslong as they were equipped with the appropri-ate pilot beam needed for phase control of thetransmitting antenna. The reference rectennawould be composed of billions of dipole an-

Ch. 5—Alternative Systems for SPS Ž 71

tennas placed above a transparent wire grid.The microwave energy received by each dipolewould pass through a rectifier circuit thatwould convert it to dc power at high currentand low voltage. Several more conversionswould be necessary to condition the power forthe grid. The received power would first beconverted to ac and then transformed to high-voltage low-current 60-cycle ac power andthen either fed into ac transmission lines fordelivery to the users or reconverted to high-voltage dc for transmission, a relatively newtransmission technology.

Estimates of overall rectenna conversion ef-ficiency run from about 80 to 92 percent, andthe extreme simplicity and repetitive-elementconstruction of the electrical componentswould facilitate mass production at extremelylow unit cost. Reliability of the rectennashould be extremely high, because each com-ponent would be ultrareliable and could oper-ate redundantly. Hence replacement would benecessary only after a large number of individ-ual failures.

None of the substation equipment involvestechnological advances beyond those that areprojected through normal development by theelectric utility industry. The major concernthat has been expressed is the large scale ofthe minimum individual power unit. Currentgrid control systems are quite adequate to han-dle near-instantaneous switching of singlepower units as high as 1,300 MW. Single unitvariations of 5,000 MW could present majorcontrol difficulties to the utilities as they cur-rently operate10 11 (see ch. 9 for a detaileddescription of utilities interface problems).

SPACE CONSTRUCTIONThe mass and physical size of the space seg-

ment needed for an operational 5-GW satellitepower station are larger by several orders ofmagnitude than any space system heretoforelaunched and therefore require careful con-

‘“J. G. Bohn, J. W. Patmore, and H W Faininger, “SatellitePower Systems: Utility Impact Study,” EPRI AP-1 548 TPS 79-752,September 1980.

11 p j, Donalek, and J. L. WhYsong, “Utility Interface Require-ments for a Solar Power System, ” Harza Engineering Co ,DO E/E R-0032, September 1978

sideration of the transportation options. Thebasis for all projected Earth-to-low-orbittransportation concepts is the current U.S.space shuttle, scheduled to become the opera-tional mainstay of the U.S. (and much of theworld’s) space program.

Of the many possible shuttle derivatives andother new transportation prospects, 12 NASAselected four different types of vehicles to sup-ply the four basic transportation functions:

●

●

●

●

The

carrying cargo between Earth and low-Earth orbit (LEO),carrying personnel between Earth andLEO,transferring cargo between LEO and thegeosynchronous orbit (CEO), andtransferring personnel between LEO andCEO.

designs of these four vehicles, called re-spectively, the heavy-lift launch vehicle(HLLV), the personnel launch vehicle (PLV), thecargo orbital transfer vehicle (COTV), and thepersonnel orbital transfer vehicle (POTV), arebased on existing technology, although allwould require considerable development be-fore reaching operational status. 13 14 15 16

Both the HLLV and the PLV would utilizefully reusable flyback boosters similar to thoseoriginally considered by NASA in early shuttledesigns in the late 1960’s. Both boosters wouldemploy methane-oxygen rocket engines for(vertical) takeoff and airbreathing (turbofan)engines for flyback to base for horizontal land-ings. The HLLV orbiter would use oxygen-

“Robert Salkeld, Donald W Patterson, and Jerry Grey (eds ),‘Space Transportation Systems, 1980-2000, ” VOI 2, AlAA Aero-

ipace Assessment Series, A IAA, New York, 1978‘‘G Woodcock, “Solar Power Satellite System Definition

Study, ” Boeing Aerospace Co., Johnson Space Center contractNo NAS9-I 5196, pt 1, report No D180-20689, June 1977; pt 11,report No D180-22876, December 1977, pt I I 1, report NoD180-24071, March 1978

“C Hanley, “Satellite Power System (SPS) Concept Defini-tion, ” Rockwell International Corp., Marshall Space Flight Cen-ter, contract No NAS8-32475, report No SD78-AP-0023, April1 ’378

15 Gordon R Woodcock, “Future Space Transportation Sys-tems Analysis Study, ” Johnson Space Center contract No.NAS9-I 4323, Boeing Aerospace Co. report No DI 80-20242-1(three volumes), Dec. 31,1976

“Donald P, Hearth (Study Director), “A Forecast of SpaceTechnology 1980-2000,” NASA SP-387, January 1976.


hydrogen rockets essentially identical to thoseof the current space shuttle, and then glideback to base much like the shuttle does. Un-like the shuttle, it would be fully reusable; itwould have no disposable external propellanttank.

The PLV orbiter would be very much like thecurrent space shuttle, but would employ a pas-senger-carrying module in the payload bay.Like the shuttle, it would also use a disposableexternal propellant tank, but a somewhatsmaller one. It couId carry 75 passengers, plusthe normal shuttle crew.

A fleet of COTV, all reusable, would makethe round trip from LEO to CEO, carrying thecargo payloads up to CEO and returningempty to LEO for reuse. They would be pro-pelled by efficient but slow electrostaticengines. Using low-thrust electric propulsionwould require very long trip times, of the orderof 4 to 6 months. The bases for selecting thispropulsion option were essentially minimumcost and ready availability of the argon pro-pellant and other materials. Such long triptimes, although suitable for cargo, are clearlynot acceptable for personnel, so a high-thrustpropulsion approach was chosen for thePOTV. The design utilizes a basic oxygen-hydrogen propulsion stage now undergoingresearch evaluation at NASA as part of its Ad-vanced Space Engine program. It employsessentially the same level of “technology asthat used in the current space shuttIe mainengine. It could carry up to 160 people fromLEO to CEO and back, or 98 tonnes (480 man-months) of consumables from LEO to CEO.

Because it would be impractical to launch afull-sized power satellite by single launch vehi-cle, a strategy for constructing the satellite inEarth orbit would be necessary. The basicspace construction strategy selected for thereference system is to launch all materials,components, and people to staging areas inLEO (fig. 15). The COTVs, because of theirlarge solar arrays, would be assembled in LEOas well. The main construction base would belocated in CEO, although not necessarily atthe eventual geostationary-orbit location ofthe operational SPS. Hence the LEO staging

area would serve as the transfer point for allmaterials and personnel both up to CEO andback down to Earth. Alternative strategieshave been considered, some of which will bediscussed later.

The principal factor that governs the costand effectiveness of in-space construction isgenerally accepted to be the productivity ofthe construction crew and cost, and require-ments for shielding. The replacement of somecrew by automated equipment is therefore amajor consideration in alI construction strate-gies or scenarios, e.g., effort has already beendevoted to automatic beam-building sys-tems. 17 The use of teleoperators and robot ma-nipulators for assembly of large structures hasalso been considered. The current growth oftechnology in these areas is extremely rapid, ’8and incorporation of such techniques wouldalmost certainly benefit all aspects of SPS con-struction. Despite the wide range of construc-tion options, estimated personnel require-ments for them are approximately the same:750 & 200. 19

GROUND-BASED CONSTRUCTION ,

Building the rectenna, although a very largeand relatively unique structure, neverthelesswould involve far fewer uncertainties thanconstructing the space segment. A detailedanalysis 20 of both the basic structure andconstruction aspects concluded that the pri-mary structural material should be galvanizedor weathering steel rather than aluminum(which is more scarce and requires a higherenergy cost to produce).

SYSTEM OPERATIONAn active control system would be needed

both to keep the satellite in the proper orbit

‘Denls j Powell and Lee Brewing, “Automated Fabrication ofLarge Space Structures, ” Astronautics and Aeronautics, October1978, pp 24-29

‘ 8 Antal K Bejczy, “Advanced Teleoperators,” Astronauticsand Aeronautics, May 1979, pp. 20-31

“W H Wales, “SPS Program Review Transportation Perspec-tive, ” I n The Final Proceedings of the Solar Power Satellite Pro-gram /?ev/ew, DOE/NASA Conf-800491, July 1980

‘O’’ Feaslbil ity Study for Various Approaches to the StructuralDesign and Arrangement of the Ground Rectenna for the Pro-posed Satellite, ” NASA contract No. NAS-I 5280, Bovay Engi-neers, In{ , M a y 1 9 7 7


Figure 15.—SPS Space Transportation Scenario

SOURCE: W. H. Wales, “SPS Program Review Transportation Perspective,” in The Final Proceedings of the Solar Power Satellite Proqram Review, DOE/NASAConf-800491, July 1980. -

(stationed above the rectenna) and to maintainthe solar array’s orientation to the Sun. Themass of the necessary control system is esti-mated at 200 tonnes; its average electric powerconsumption would be 34 MW.

Because of its low coefficient of thermal ex-pansion and relative stiffness, a graphite com-posite structural material was selected for thereference system in preference to the alumi-num alloys so widely used in aerospace struc-tures. Although a complex engineering prob-lem and, furthermore, one not readily subjectto testing at an adequate scale prior to deploy-ment in space, it does not appear likely thatdynamic stability would cause any major unex-pected problems in either performance or

83-316 0 - 81 - 6

costs, partly because of the predictability ofthe space environment as compared, for exam-ple, with the uncertain environment in whichaircraft structures must be designed to oper-ate, and partly because of the extensive bodyof applicable design, testing, and operationalexperience with high-performance aerospacestructures. However, questions of dynamic in-stability resulting from Iow-probability occur-rences such as major meteor strikes or aggres-sive military action would have to be eval-uated.

Orientation of the transmitting antenna rela-tive to that of the solar array would be main-tained via the large rotary joint. Physical aim-ing of the antenna itself would be accom-


plished by gyroscopes, which would feed con-trol signals to the mechanical-joint turntableso that it could follow the antenna pointing re-quirements. However, mechanical pointing ofthe antenna would not have to be performedwith high accuracy, since the electronic phas-ing and pointing of the antenna subarrayswould be insensitive to angular deflections ofthe antenna of upto100.

In addition to the equipment for satellitestation keeping and attitude control, it wouldbe necessary to provide routine maintenanceof both the space and ground segments. Poten-tial maintenance problems in the space seg-ment, in addition to the expected routine re-placement of components, include the effectsof solar wind, cosmic rays, micrometeoroids,and impacts by station-generated debris. Asidefrom the solar wind and cosmic radiation ef-fects on solar cells, which would require activeannealing of the silicon cells, none of these ef-fects would appear to introduce significantmaintenance problems or costs, based on ex-tensive past and current experience with oper-ational satellites powered by photovoltaiccelIs.

Repair and replacement of the solar blan-kets and more than 100,000 70-kW klystrons inthe transmitting antenna are estimated to re-quire a crew of from 5 to 20 people at thegeostationary orbit construction base,21 alongwith the necessary transportation, support,and resupply (e. g., station-keeping propellant)services.

Maintenance requirements of the rectennaand substation are also primarily associatedwith repair and replacement of their biIIions ofcomponents. Although a certain degree of re-dundancy is built into the system, a mainte-nance crew would still be required to replacestorm-damaged rectenna sections and routinefailures of both rectenna and substation equip-ment.

Technical Uncertainties ofthe Reference System

Although most observers accept the basicscientific feasibility of the SPS system con-

2’ DOE, op cit

cept, there are many technical uncertaintiesassociated with the reference system. This sec-tion identifies specific issues or problems inthe reference system that would be of impor-tance in formulating decisions concerning theresearch, evaluation, development, demon-stration, and deployment of satellite powerstat ions.

●

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●

Performance. A major issue in the referencesystem design is the tremendous scale of thesatellite. The level of 5 GW (net outputpower) is based on scaling assumptions thatcould be subject to considerable change(e.g., the transmission frequency, the an-tenna and rectenna power densities); multi-ple rectennas served by a single satellite alsoconstitute a potential variation.

The overall efficiency of the entire systemwould be subject to considerable variationeither up or down, and would be a key factorin all cost and technology tradeoffs. Al-though all system elements would involveknown technology, there is considerable un-certainty about how their efficiencies mightadd up when assembled together.

Powerplant lifetime, assumed to be 30 yearsfor the reference system, could actually begreater or less depending on a number ofeconomically interrelated factors (e. g., easeof replacement of damaged components,sudden technological advances in compo-nent efficiencies, etc.) This would affect alleconomic projections, even allowing forhigh-discount rates.

The total mass in orbit, one of the criticalparameters in assessing costs and launch-related environmental impacts, depends ona number of factors stilI subject to consider-able variation. The power CoIlection/conver-sion system is an obvious factor; the refer-ence system’s two photovoltaic options areindicative of the significance of that trade-off. The antenna mass is also important.Prospects for revising the reference-system’s100:1 ratio of rectenna-to-antenna areacould have major impact on the overall sys-tem cost and performance. The 25-percentcontingency factor is another major factorsubject to revision if R&D mature.


SPS would require an extensive program ofresearch and testing of the numerous satelliteand terrestrial components of the systembefore planning for a demonstration satellitecould be completed. In addition, substantialimprovements in components and overall tech-nology would have to occur before the SPScould meet the performance specifications ofthe reference system. However, the currentreference system does not constitute a pre-ferred system. It is, perhaps, technically feasi-ble but certainly not an optimum design. It waschosen by NASA/DOE as a model and a refer-ence to be used in the assessment process. Assuch it has the inherent I imitation that as newinformation becomes available the design be-comes progressively obsolete.

The following items summarize the majortechnical uncertainties for the reference sys-tem and suggest possible ways to alleviatethem.

. Photovoltaic cells. The reference systemspecifies a silicon solar cell efficiency of17-percent and a mass of 2 grams per peakwatt (g/Wp). Current space-rated singlecrystal silicon cells operate at 12- to 16-percent efficiency. However, they areabout nine times as massive (18 g/Wp) ascalled for in the reference system andthey cost about $70/Wp (1980). The refer-ence system assumes a cell cost of about$0.17/Wp. Although the issue of costs willbe addressed in more detail in a separatesection, it is clear that meeting all threegoals for the silicon cell blanket wouldpresent manufacturers of current celltechnology with an extremely difficulttask. Normal advances in cell productiontechniques would readily result in thenecessary efficiency increase. However,the burden of achieving a nine timesreduction in weight along with a reduc-tion in costs of a factor of 400 makes ithighly unlikely that an SPS could be builtusing single crystal silicon cells.

If efficiency-mass-cost goals were met,there would still be the problem of celllifetime in space and the related problemof the feasibiIity of annealing the surface.

Silicon cells are subject to serious degra-dation by high energy electrons and pro-tons in the solar wind released by solarflares. One study” estimates that the ac-cumulated particle damage would de-grade the output from the cells by 30-percent during the 30-year nominal life ofthe satellite. The resulting damage couldbe repaired periodically by annealing thecells by either a laser or an electron beam.The beam would sweep across the surfaceof the cells and heat them briefly to sev-eral hundred degrees centigrade. Very lit-tle is known about either process in thelaboratory and nothing at ail about howthey would work in space or how muchenergy they would use to anneal the sur-face of the photovoltaic cells. However,experiments have shown that annealingby electron beam is much more efficientthan laser annealing.23 Because no long-term studies have been done, the suita-bility of silicon cells for extended dura-tion space applications is in question;however, they have demonstrated ex-cellent performance over a period ofabout 10 years in operating spacecraft.

GaAs cells appear to be a more realisticcandidate for a reference-type satellite,though they have received much less at-tention than the silicon cells. GaAs cellsreach higher efficiencies and can operateat higher ambient temperatures than sili-con cells. Laboratory models of GaAscells have reached efficiencies as high as18 percent. 24 Because of their currentlyhigher unit cost, the GaAs array wouldprobably require refIectors to concentratethe Sun’s rays on the cells and therebyreduce the required cell area. AluminizedKapton has been suggested as a reflectivematerial because of its low thermal coeffi-cient of expansion and low mass density.

2*C R Woodcock, “SPS Silicon Reference System,” The Fina/Proceedings of the Solar Power Sate//ite Program Review,DOE/NASA Conf-800491, July 1980,

“B E. Anspaugh, J. A Scott-Monck, R. G. Downing, D W.Moffett, and T. F Miyahira, “Effects of Electrons & Protons onUltra Thin Silicon Solar Cells, ” J PL contract No, NAS7-1OO.

“lbld


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Here, again, whether Kapton and GaAscells can maintain their integrity over the30-year design lifetime of the satellite isunknown. Considerably more study wouldbe needed to determine the feasibility ofthis option.Space charge and plasma effects. Becauseof the high voltages associated with oper-ation of the klystrons, electrical chargebuildup in the satellite components couldcause arcing and subsequent failure ofcertain components.Rotary joint/slip rings. Although the basictechnology of building a rotary joint andan associated slip ring (for electrical con-tinuity) is well-known, considerable uncer-tainty surrounds their construction andoperation on the scale of the referencesatellite in a space environment. Becauseit would operate in a gravity-free environ-ment, the design demands would be dif-ferent than they are for terrestrial designs.Klystrons. Current klystrons last about 10years, but these are tubes especially se-lected for their long life characteristicsand they operate at much lower powerlevels than the 70 kW required of refer-ence system klystrons. High-power klys-trons do exist, but they operate in a pulsedmode, not continuously as the referencesystem klystrons would have to. The an-tenna’s phased array control systemwould need considerable developmentand testing. Although pilot beams havebeen used in other applications, and thetechnology is therefore known, it isunclear whether the power beam wouldleave the ionosphere sufficiently unaf-fected to allow for undisturbed passage ofthe pilot control beam.

Although harmonics and other noiseproduced by the klystron or alternativetransmitting device would seem unlikelyto affect the natural environment adverse-ly, they could cause radio frequency inter-ference for communications systems (seethe discussion of ch. 8). This problemmight be severe and wouId need extensivestudy, but most experiments could be car-ried out in ground-based testing. Alter-

●

●

natives to the klystron may provide betternoise and harmonic control (see sectionon alternatives below).Space transportation. The problems inher-ent in developing the capability to trans-port SPS components to LEO and CEO arethose of extending a mature technology,i.e., there is sufficient understanding ofthe problems to be faced that there is lit-tle doubt that the appropriate vehiclecould be developed. The most importantquestion is whether the necessary massiveloads could be transported for sufficientlylow costs, i.e., would reusable vehiclesprove economic? In this area, much canbe learned from experience with the shut-tle

I n addition to economic concerns, thereare additional technical questions relatingto environmental effects that would re-quire study. For instance, can the launchvehicles fly trajectories that would keepthe effects of ionospheric contaminationto a minimum? Would it be possible tosubstitute other technologies for theargon ion engine proposed for the refer-ence system (see ch. 8).Construction, operations, and mainten-ance. There are unresolved questionsabout the productivity of humans and ma-chines in the space environment. Someautomated equipment has been built andtested on Earth, but considerable develop-ment would be needed to choose the bestratio between automated and humantasks.

Alternatives to the ReferenceSystem Subsystems

One of OTA’s goals is to explore the possiblealternatives to the reference system. Some op-tions improve specific components of the ref-erence system. Others would require signifi-cant redesign of the overall system. This isbecause the reference system is composed of anumber of interlocking components, some ofwhich depend heavily on the other elements ofthe system. Thus, a radical change in one com-ponent might require numerous other system

Ch. 5—Alternative Systems for SPS • 77

changes in order to create the most efficientoverall design.

A number of alternative subsystems and sys-tems were considered in the process of elect-ing the reference system design. Advanceshave been made in some components thatwere previously rejected. In addition, consid-eration of some of the above-mentioned tech-nical uncertainties has engendered new de-signs that could alleviate these uncertaintiesor resolve some of the technical problems en-countered in the reference system.

The following summary lists a number ofsubsystem options that could be considered asalternatives to the reference system. A moredetailed discussion of each can be found in ap-pendix A.

Solar thermal power conversion. Either aBrayton- or Rankine-cycle engine offershigher efficiency energy conversion thanphotovoltaics. However, they currentlysuffer from limitations on the means forheat rejection.

Thermionic, magnetohydrodynamicor wave energy exchanger technologiesmight eventually find use in combinationwith the Rankine or Brayton cycle.Photovoltaic alternatives. Materials otherthan silicon or gallium arsenide may even-tually prove more viable for use in theSPS. Currently none of the other obviousoptions meet the projected standards forefficiency, low mass, materials availabili-ty, etc., that would be needed for satelliteuse. Different sorts of concentrator sys-tems are also of interest, as is the possi-bility of using single cells or a combina-tion of cells that respond to a wide por-tion of the solar spectrum. A possible ap-proach would be to use a combination ofal I these variations.Alternative microwave power converters.Several devices other than the klystronhave been considered for converting elec-tricity to microwaves and transmittingthem to Earth including the magnetron,which offers the principal potential ad-vantage of cost and low noise, and thesolid-state amplifier whose reliabilitycould be very high and mass low.

● Photoklystron. This device, which is stilI inthe very early stages of study, both con-verts the sunlight directly to microwavepower, and transmits it. If successful, itcould replace both photovoltaic cell andamplifier.

● Offshore rectennas. For highly populatedEuropean and U.S. coastal areas, recten-nas mounted in the shallow offshore sea-beds offer some advantages over longtransmission lines from suitable land-based rectennas.

THE SOLID-STATE SYSTEM

Two system approaches using solid-statedevices have been considered for the SPS. Themost direct of these simply replaces the kyls-trons and slotted waveguides in the referencesystem by solid-state amplifiers and dipoleantennas maintaining essentially the samebasic configuration as that of the referencesystem (fig. 9); the second approach complete-ly revises the satellite configuration by inte-grating the antenna and solar array in theEarth-facing “sandwich” configuration, using amovable Sun-facing mirror to illuminate thesolar array (fig. 16). A number of alternativesandwich configurations have been exploredbut at the moment the configuration of figure16 seems to be the best.25

Another related subsystem option uses themultibandgap photovoltaic cells discussedearlier, possibly in conjunction with selectivefiltering to reduce solar-cell temperatures.When such cells are utilized in the sandwichconfiguration of figure 16, they offer consid-erable potential mass reduction. A recent pre-liminary case study26 compared sandwich-typesystems such as that of figure 16 employingsingle-bandgap GaAs photocelIs similar tothose of the reference system but having high-er concentration ratios (CR) with optimizedmultibandgap photovoitaics. Such a configu-ration would result in an approximate W-per-cent increase in power delivered per kilogram.

“G M Hanley, et al , “Satellite Power Systems (SPS) ConceptDeflnitlon Study, ” First performance Review, Rockwell interna-tional report NO SSD79-01 63, NASA MSFC contract NoNAS8- )2475, Oct 10, 1979

~bl bld


Figure 16.—The Solid-State Variant of the Reference System

Reflected sunlight

Detail of solar cellblanket panel

Solid-stateamplifierpanel

Sunlight I

Microwave /p o w e r t oE a r t h

/ ’Solar array/microwave antennasandwich panels

SOURCE: G. M. Hanley, et al., “Satellite Power Systems (SPS) Concept Definition Study, “First Performance Review, Rockwell International reportNo. SSD-79-0163, NASA MSFC contract No. NAS-8-32475, Oct. 10, 1979.

LASER TRANSMISSION

Lasers constitute an alternative to micro- ●

wave transmitters for the transmission ofpower over long distance. 27 They offer the fun-damental advantage that at infrared wave-lengths, energy can be transmitted and re-ceived by apertures over a hundred timessmaller in diameter than the microwave beam.This obviously would reduce the size and massof the space transmitter and the land-area re-quirement of the ground receiver. But perhapseven more important, the great reduction inaperture area would permit consideration offundamentally different systems. For example:

W H p o w e r

Satellites: The Laser Option,” Ast ronaut ics a n d A e r o n a u t i c s ,

March 1979, pp. 59,67,

The use of low Sun-synchronous ratherthan high geostationary orbits for the mas-sive space power conversion subsystemmight be possible. (A Sun-synchronous or-bit is a near-polar low orbit around theEarth that keeps the satellite in fullsunlight all the time while the Earth ro-tates beneath it.) In this suggested system,the laser would beam its power up to low-mass laser mirror relays in geostationaryorbit for reflection down to the Earthreceiver, an arrangement that might con-siderably reduce the cost of transporta-tion, since the bulk of the system mass isin LEO rather than in GEO. However, sys-tem complexity would be increased dueto the need for relay satellites.

Ch. 5—Alternative Systems for SPS ● 7 9

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●

Because the mass of the laser transmitterswould not dominate the satellite, as doesthe reference-system microwave transmit-ter, laser satellites would not benefit near-ly so much by large scale as the referencesystem satellites. The resulting smallersystems would improve the flexibility ofterrestrial power demand matching, pro-vide high degrees of redundancy, permit asmaller and therefore less costly systemdemonstration project, and might evenpreclude the need for ultimate develop-ment of an HLLV.The small size of the receiving stationwould make it possible to employ multi-ple locations close to the points of use,thereby simplifying the entire ground dis-tribution and transmission system. Itwould also open up the possibility ofrepowering existing powerplants, regard-less of their size, simply by replacing theirsteam generating units with laser-heatedboilers and/or superheaters.

The most important technical disadvantagesof laser-power transmission are the very lowefficiencies of present laser-generation andpower-conversion methods, low efficiency oflaser transmission through clouds and mois-ture, and the relatively undeveloped status oflaser power-system technology in general.

The laser system would consist of threedistinct elements: the laser-generation sub-system, the laser-to-electric power-conversionsubsystem, and the laser beam itself.

Laser Generators

Although the laser has become a well-knownand widely utilized device in industry, thehigh-power continuous-wave (CW) laser gen-erators needed for SPS are still in theadvanced-technology or, in many cases, theearly research phase.28 However, the technol-ogy is improving dramatically as exemplifiedby the growth of laboratory-demonstrated con-version efficiencies (input power to laser

beam) from about 1 to nearly 50 percent dur-ing the past decade.

Of all the currently operating CW lasers,only the electric discharge laser (EDL)29 seemsa feasible alternative for the SPS. The gas dy-namic laser (CDL) suffers from very low effi-ciency if used in the closed cycles necessaryfor space (i.e., the gas supply must be circu-lated, cooled, and reused). Chemical lasers re-quire a continuous propellant supply thatmakes them also unsuitable for long-term usein space.

High-power density at 50-percent conversionefficiency levels has been achieved for EDLs,but only in the open-cycle mode for short timeperiods. The closed-cycle systems needed forSPS have yet to be tested, even in the labora-tory. In theory, they should achieve high effi-ciencies in that mode as well, but considerableimprovement in the available technologywould be required to reach the necessarygoals.

In addition to using improved designs of cur-rently operating lasers, several advanced con-cepts have been suggested. Of these, the solar-pumped laser and the free electron laser (FEL)seem most promising for the long term.

● Solar-pumped lasers. Figure 17 illustratesthe concept of a solar-pumped laser. Theenergy contained in sunlight directly ex-cites a combination of gases confined be-tween two mirrors, which subsequently“lase” and transmit the captured energy.It suffers the drawback that because onlya part of the solar spectrum is useful in ex-citing any given Iasant gas, its conversionefficiency is likely to be fairly low. How-ever, elimination of the need for a sepa-rate electric power-generating system,and the consequent reduction in mass andcomplexity, could more than compensatefor this drawback. Further, in comparisonwith other laser systems, the solar-pumped laser’s efficiency need be only asgood as the combined power-generating

28j Frank Coney bear, “The Use of Lasers for the Transmissionof Power, ” in Progress in Astronautics, vol. 61, A IAA, N Y ,)ui~ 1978, pp. 279-310

“G W Kelch and W. E. Young, “Closed-Cycle GasdynamicLaser Design Investigation, ” Pratt & Whitney Aircraft, NASALewis Research Center report No CR-135530, Jan 1,1970.


Figure 17. —Indirect Optically Pumped CO/CO2 Mixing Laser

Ps QSEP

solar n

SOURCE: R. Taussig, P. Cassady, and R. Klosterman, “Solar Driven Lasers for Power Satellite Applications,” in Firra/ Proceedings of SPS Program Review, Department of Energy, p. 267

system and laser generator of other lasersystems (about 7.5-percent for a photo-voltaic-powered carbon monoxide (CO)EDL30).

Although the information exists to deter-mine the applicabiIity of solar-pumped lasersto SPS, adequate studies have not been done.There is as yet little or no realistic basis for themass, efficiency, and cost projections pro-posed by several authors.31 32 33 34

‘“R. E. Beverly, “Satellite Power Systems (SPS) Laser StudiesTechnical Report, Vol. 1, Laser Environmental Impact Study,”Rockwell International SSD-80-0119-I, August 1980

“W. S. Jones, L. L. Morgan, J. B, Forsyth, and J Skratt, “LaserPower Conversion System Analysis: Final Report, Vol. I l,” Lock-heed Missiles and Space Co., report No LMSC-D673466, NASAreport No. CR-1 59523, contract No NAS3-21 137, Mar 15, 1979

32 Claud N Bain, “Potential of Laser for SPS Power Transmis-sion, ” report No R-1 861, PRC Energy Analysls Co , DOE contractNo. EG-77-C-01-4024, September 1978

3JJohn D. G. Rather, “New Candidate Lasers for Power Beam-ing and Discussion of Their Appl icatlons, ” I bid,, pp. 313-332.

34 Daryl J. Monson, “Systems Efficiency and Specific Mass Esti-mates for Direct and Indirect Solar-Pumped Closed-Cycle High-Energy Lasers in Space,” ref 105, pp 333-345

Free-Electron Lasers (FEL)

An FEL is powered by a beam of high-energyelectrons oscillating in a magnetic field in sucha way that they radiate in the forward direc-tion (fig. 18). A number of pulses reinforce thestored light between the mirrors, generating acoherent laser beam. The high-energy densityof the relativistic electron beam is theoreti-cally capable of producing very high-powerdensity lasers, and the emitted frequency istunable simply by changing the electronenergy.

Although efficiencies are theoretically pro-jected to be quite high (around 50 percent forthe combined FEL and storage ring35), it is notknown whether such efficiencies could bereached in practice. In addition, the systemmass per unit power output and the ability to

‘5John W Freeman, William B. Colson, and Sedgwick Simons,“New Methods for the Conversion of Solar Energy to R. F. andLaser Power, ” in Space Manufacturing ///, Jerry Grey andChrlstlne Krop (eds ) (New York AlAA, November 1979).


Figure 18.—The CATALAC Free Electron Laser Concepts

SOURCE: R. Taussig, P. Cassady, and R. Klosterman, “Solar Driven Lasers for Power Satellite Applications,” in Final Pro-ceedings of SPS Program Review, Department of Energy. p. 267

scale to the size and power levels of a laserSPS are impossible to predict reliably at thistime. 36

Laser Transmission

As in the case of microwave transmission,the fundamental parameter that governs muchof laser transmission performance is the fre-quency (or wavelength). At ultraviolet or visi-ble wavelengths, absorption losses in the at-mosphere are higher than for infrared wave-lengths. The wavelength also affects the effi-ciency of the laser power absorption and con-version equipment.

At the wavelengths of CO or CO, EDLs, (5 to10 microns), the primary mechanism of beamattenuation is molecular absorption. Scatter-ing by molecuIes or by aerosols in clear air isrelatively unimportant. Attenuation of thebeam by aerosols under hazy or cloudy condi-tions is quite significant and can completelyblock the beam if the clouds are thick enough.Although it is apparently possible to burn ahole through thin clouds,37 the attenuation ofenergy is appreciable, and because clouds areseldom stationary, the laser would continuallyencounter new water droplets to vaporize.

‘s Beverly, op. cit.37E. W. Walbridge, “Laser Satellite Power Systems, ” Argonne

National Laboratory report No AN L/ES-92

Transmission of the laser beam through theatmosphere is also affected by a phenomenoncalled “thermal blooming;” i.e., heating of theatmosphere that causes it to act Iike a lens anddistort the laser beam. Scientists are currentlydivided on the significance of this issue andopinions range from assertions that it is a ma-jor factor38 to suggestions that it couldbe avoided altogether by selecting the trans-mitting wavelengths carefully.39 Considerableclassified research is now being carried out onthis effect in connection with laser-weaponsresearch. Some of this work might be applica-ble to SPS use, though in general the militarylasers are pulsed, not CW systems. The differ-ence could be critical and should be studiedcarefulIy.

With regard to laser optics, it is important todevelop components capable of low-loss, high-power-density transmission and reflection oflaser light.40 It appears that adequate tech-nology for SPS systems has a high probabilityof being available within the next 20 to 30years, due primarily to advances being made incurrent military laser research and technologyprograms.

“Jones, et al , op cit“Beverly, op. cit40 Baln, op cit


Transmission options for SPS lasers areessentially of two types: a narrow, highly con-centrated beam or a wide, dispersed beam (fig.19). Advantages of the narrow beam are thereduced land area needed and the smalI size ofthe ground power-conversion system; prob-lems include potential environmental andsafety impacts of the high-intensity beam, con-cerns over military uses, and the need for so-phisticated high-temperature receivers andpower-conversion equipment. Advantages ofthe dispersed beam are its less severe environ-mental impact, the possible use of low-per-formance optics, and simplicity of low-power-density receiving systems. Disadvantages in-clude relatively high atmospheric dissipation,larger land area required and the large mass ofEarth receptors. It is probably too early tomake an informed selection between the twooptions, but the narrow-beam approach ap-pears to offer the principal benefit comparedto reference-system microwave transmission.

A final concern is the ability to point andcontrol the beam to make sure it would alwaysremain within the designated receiver area andto shut it off instantly should it stray. Theadaptive-optics approach to beam control(e.g., phased-array) such as would be used forthe microwave beam, appears adequate toprovide the necessary pointing accuracy andto ensure safety, since any loss of phasing con-trol would cause loss in coherence of the sev-

eral lasers making up the beam, and eachbeam by itself would transmit far too littlepower to cause any problems. Adaptive opticssystems are being studied for use in militarydirected energy weapons and look promising.”It should be emphasized that the overall sys-tem constraints might be quite different forthe large CW lasers needed for SPS than forpulsed military examples.

Laser-Power Conversion at Earth

Several approaches are possible for convert-ing high-energy-density laser radiation to use-ful electric power. The technology of laserenergy converters is relatively new, but prog-ress has been rapid. Laboratory models haveachieved conversion efficiencies of 30 to- 40percent and designers project eventual effi-ciencies of 75 percent for some versions. Table6 summarizes the available technology andprojects future potential efficiencies. 42

The Laser-Based System

Lockheed 43 has generated one possible lasersystem (fig. 20) that utilizes power satellites in

4’Claud N Bain, “Power From Space by Laser,” in “High-Pow-ered Lasers In Space, ” Ast ronaut ics a n d Aeronaut ics , vol. 17,March 1979, pp 28-40

“(;eorge Lee , “S ta tus and Summary o f Laser Energy Conver-sion, ‘ In Progress in As t ronaut i cs , VOI 61 Al AA, N Y , July1978 pp 549-565

4’Jones, et al , op clt

Figure 19.—Optics and Beam Characteristics of Two Types ofLaser Power Transmission System (LPTS) Concepts

Optics Optics

m

SOURCE: Claud N. Bain, “Potential of Laser for SPS Power Transmission,” report No. R-l WI,PRC Energy Analysis Co., DOE contract No. EG-77-C-01-4042, September 1978.


Table 6.—Projections for Laser Energy Converters in 1981-90

Current 1981-90

Photovoltaics. . . . . . . . . . . .

Heat engines . . . . . . . . . . . .

Thermionics . . . . . . . . . . . . .

Photochemical cells . . . . . .

Optical diodes . . . . . . . . . . .

—30% efficiency—megawatt power levels—wavelengths below 1 micron

—Piston engine: Otto or diesel cycles—50% efficiency—1-10 k W—wavelengths near 10.6 microns

—40% ef f ic iency—1-10 kW—wavelengths near 10.6 microns

—Photoassisted dissociation of water—15Y0 efficiency—wavelengths near 0.4 microns

—Evaporated junction arrays—not ready to convert power

—45% efficiency—megawatt power levels—wavelengths below 1 micron

—Turbine—75% efficiency—megawatt power levels—wavelengths near 5 microns

—50% efficiency—megawatt power levels—wavelengths near 5 or 10 microns

—Photoassisted dissociation of water—30% efficiency—wavelengths near 0.6 microns

— Evaporated junction arrays—50% efficiency—megawatt power levels—respond to wavelengths from UV to

over 10 microns

SOURCE: George Lee, “Status and Summary of Laser Energy Conversion, “ in Progress in Astronautics, vol. 61, AlAA, N. Y., July 1978, pp. 549-565.

low Sun-synchronous orbit and relay satellites(laser mirrors) both in LEO and CEO. One geo-stationary relay serves each power satellite.Based on an analysis of five candidate systemsin three power ranges, Lockheed selected aCO, EDL powered by a wave energy exchanger(EE) binary cycle and a similar binary cycle forground power conversion.

The specific 500 MW system selected is dia-gramed in figure 21; hardware details of thepower satellite appear in table 7, and the Over- .

all system characteristics are summarized intable 8.

A major potential advantage of the lasersystem is that it could be demonstrated via asubscale 500-kW pilot program using the spaceshuttle to deliver the power and relay satellitesinto LEO orbits.

Other laser systems are possible. For exam-ple, Rockwell44 has investigated a geosyn-chronous laser SPS powered by photovoltaicceils and using 20 to 24 100-MW CO EDLlasers. The CO laser was chosen because it hasgreater overall efficiency and is lighter than aC 02 laser.

This study will use the LEO-based C02 lasersystem in its subsequent analysis because of

‘*Beverly, op. cit.

the significant difference in space basing (i. e.,LEO rather than CEO) which it presents com-pared to the reference system. Because of thesignificant uncertainties present in the lasersystems concepts and the relative lack of tech-nology base for laser devices, the optimumlaser system would undoubtedly look ratherdifferent from any system so far devised.

A laser system that used photovoltaic arraysto collect and convert the Sun’s energy wouldsuffer from the fundamental difficulty that theoveralI efficiency of the system wouId be quitelow compared to projected reference systemefficiency .45 The major limiting factors are theprojected efficiencies of the laser itself (50 per-cent for an EDL), the atmospheric transmis-sion (84 to 97 percent), and the conversion effi-ciency of the terrestrial receptor (40 to 75 per-cent). When multiplied together with thehigher efficiency of other system components,they result in an overall efficiency of 17 to 36percent after photovoltaic conversion of sun-light to electricity to power the laser. When theefficiency of the solar cells (17 percent) istaken into account, the overalI system efficien-cy falls to only 2.8 to 6 percent compared tothe projected reference system efficiency of 7percent. Although this decrease would con-

45D0E, op. cit.

Ground site

SOURCE: W. S. Jones, L. L. Morgan, J. B. and J. “Laser Power Conversion Analysis: Final Report, Vol. Lockheed Missiles and SpaceCo., report No. NASA report No. CR-159523, contract No. 137, Mar. 15, 1979.

Figure 21 .—Components of the Laser Concept

Synchronous relays

Occulted ,Power

SOURCE: W. S. Jones, L. L. Morgan, J. B. and J. “Laser Power Conversion System Analysis: Final Report, Vol. 11,” Lockheed Missiles and Space Co.,report No. NASA report No. CR-159523, contract No. 137, Mar. 15, 1979

Ch. 5—Alternative Systems for SPS • 85

Table 7.—500 MWe Space Laser Power System

Powergeneration Spacecraft,

EE/binary and structure, Transmitter apertureCollector Solar cavity cycle conditioning Laser radiators, etc. and optical train

Unit efficiency (%) . . . . . 85 86 73.5 93.1 23 98.7System efficiency (%) . .

—

85 73.1 53.7 50.0 11.5 — 11.4Power in (MW). . . . . . . . . 7,913 6,726 5,784 4,251 3,958 910Power out (MW). . . . . . . .

—6,726 5,784 4,251 3,958 910 899

Orbital weight (kg) . . . . . 242,850—

517,750 1,326,330 717,660 1,809,000 128,653 97,811Spacecraft 4,108 Telescope (2)

89,812Structure 94,433 Beam reduction

5,379Radiators 6,032 Phasing array

1,539Stabilization Optical train 1,181

24,080

Space Atmospheric Ground Thermal Binary Electricaltransmission Space relay transmission receiver cavity cycle generation

Unit efficiency (%) . . . . . 95 99 85 96 98 75.5 98System efficiency (%) . . 10.8 10.7 9.1 8.7 8.5 6.5 6.3Power in (MW). , . . . . . . . 899 854 845 718 690 676 510Power out (MW). . . . . . . . 854 845 718 690 676 510 500Orbital weight (kg) . . . . . – 105,438 — — — — —

Transmitter 44,703Receiver 46,729Optical train 945Spacecraft 5,900Radiators 5,762Structure 1,023

Miscellaneous 376

SOURCE: W. S. Jones, L. L., Morgan, J.B. Forsyth, and J. Skratt, “Laser Power Conversion System Analysis: Final Report, Vol. 11,” Lockheed Missiles and Space Co.,report No. LMSC-D673466, NASA report No CR-159523, contract No. NAS3-21 137, Mar 15, 1979.

Table 8.—Laser Power Station Specification

Solar power collected (MW). . . . . . . . . . . . . . . . . 7,913.0Collector diameter(m). . . . . . . . . . . . . . . . . . . . . 2,710.0Electrical power to laser(MW) . . . . . . . . . . . . . . 3,958.0Laser power output (MW) (20 lasersat 45.5 MW each). . . . . . . . . . . . . . . . . . . . . . . . . 910.0

Transmitter, aperture diameter (m). . . . . . . . . . . 31.5Secondary mirror diameter (o). . . . . . . . . . . . . . . 3.0Transfer mirror size (m) . . . . . . . . . . . . . . . . . . . . 3.0 x 4.2Mirror reflectivity (%). . . . . . . . . . . . . . . . . . . . . . 99.85Optics heat rejection (MW) . . . . . . . . . . . . . . . . . 11.8Radiator area (m2). . . . . . . . . . . . . . . . . . . . . . . . . 2,656.7Mirror operating temperature (“C) . . . . . . . . . . . 200.0

stitute a potential problem for the lasersystem, it must be emphasized that many othercomplex factors (e. g., the smaller terrestrialreceivers, or lower mass in GEO), might com-pensate in complex ways for lower efficiency.When added up, the combination might makethe laser system more acceptable overall thanthe microwave systems. ’b

“Abraham Hertzberg and Chan-Veng Lau, “A High-Tempera-

SOURCE: W. S. Jones, L. L., Morgan, J. B. Forsyth, and J. Skratt, “Laser Powerture Ranklne Binary Cycle for Ground and Space Solar AppIica-

Conversion System Analysis: Final Report, Vol. 11,” Lockheed tions, ” m “Radiation Energy Conversion in Space, ” K W,Missiles and Space Co., report No. LMSC-D673466, NASA report No. Billman (cd,), Progress in Astronautics and Aeronautics, vol. 61CR-159523, contract No. NAS3-21137, Mar 15, 1979. (New York, AlAA, July 1978), pp 172-185.


MIRROR REFLECTION

Instead of placing the solar energy conver-sion system in orbit as in the reference SPS,several authors have suggested using large or-biting mirrors to reflect sunlight on a 24-hourbasis to ground-based solar-conversion sys-tems. 4 7 4 8 4 9 5 0

Typically, this option would use plane mir-rors (fig. 22) in various nonintersecting low-altitude Earth orbits, each of which directssunlight to the collectors of several ground-based solar-electric powerplants as it passesover them (the so-called “SOL ARE S“ concept).

Each mirror would be composed of a thinfilm reflecting material stretched across a sup-porting structure made up of graphite-rein-forced thermoplastic. As they pass withinrange of the terrestrial receiving station, themirrors would acquire the Sun and the groundstation nearly simultaneously. They wouldmaintain pointing accuracy by means of built-in reaction wheels.

Two typical “limiting cases” have been iden-tified from among several alternatives.51 onewouId use a 1,196-km circular equatorial orbit(O 0 latitude) serving 16 equatorial ground sta-tions each generating about 13 CW (baseload,with minimum storage) and another 6,384-km40 ‘-inclination circular orbit serving four 375GW ground stations at 300 latitude. Additionalground stations in each case (to accommodatedemand growth) could be achieved simply by

47 Hermann Oberth, “Wege zur Raumschiffahrt, ” Oldenburg-Verlag, Berlin, 1929; also see “Ways to Spaceflight, ” NASA tech-nical translation TT F-662

48 Krafft A Ehricke (for example), “Cost Reductions in EnergySupply Through Space Operations, ” paper IAF-A76-24, 27th lrr-ternationa/ Astrorraut;ca/ Congress, Anaheim, Calif , Oct. 10-16,1976.

“K, W. Billman, W, P Gilbreath, and S W Bowen, “introduc-tory Assessment of Orbiting Reflectors for Terrestrial Power Gen-eration,” NASA TMX-73,230, April 1977

‘“K, W. Billman, W. P. Cilbreath, and S W Bowen, “OrbitingMirrors for Terrestrial Energy Supply, ” in “Radiation Energy Con-version in Space,” K, W, Billman (ed ), Progress in Astronautics

and Aeronautics Series, VOI 61 (New York Al AA, July 1978), pp61-80

“K. W. Billman, W. P. Gil breath, and S W. Bowen, “SolarEnergy Economics Revisited: The Promise and Challenge of Or-biting Reflector for World Energy Supply,” DOE SPS ProgramReview, June 8,1979.

increasing the orbit altitude and mirror size,which increases the size of the illuminatedground circle and thereby permits the use oflarger ground stations.52 The orbiting mirrorsthemselves could probably be quite large (upto 50 km’ each) with very low mass density53

and still maintain their required optical sur-face flatness in the presence of disturbingforces.

A mirror system would offer the followingpotential advantages:

●

●

●

●

●

●

●

●

The space segment would be simple andof low mass. It would consist only ofplanar reflective thin-film mirrors.It would minimize the need for large-scalespace operations, since recent designsallow terrestrial fabrication and packag-ing with automatic deployment i n space.The system would be modular and highlyredundant, i.e., there would be many iden-tical mirrors capable of mass production.The mirrors would operate at low-orbit al-titudes, thus not requiring the CEO trans-portation system of some other alterna-tives.It would eliminate the need for develop-ing microwave- or laser-transmitting tech-nology.The mirrors would reflect ordinary sun-light, thus eliminating many of the poten-tial damaging environmental effects dueto laser or microwave transmission.It could be used for a variety of terrestrialuses where enhanced 24-hour sunlightwouId be useful. SOLARES couId increasethe solar product fivefold over the samesystem operating on ambient sunlight.Demonstration would be very inexpensivecompared to laser or microwave options.

‘2K W Billman, “Space Orbiting Light Augmentation Reflec-tor Energy System: A Look at Alternative Systems,” SPS ProgramReview, June 1979.

“John M Hedgepeth, “Ult[ ghtweight Structures for SpacePower, ” in “Radiation Energy Conversion in SpaceJ” K W, Bill-man (ed ), Progress in Astronautics and Aeronautics, vol. 61 (New

York Al AA, j uly 1978), pp. 126-135.

Ch. S—Alternative Systems for SPS ● 87

Figure 22.–The Mirror Concept (SOLARES)


SOURCE: W. Bill man, “Space Orbiting Light Augmentation Reflector System: A Look at Alternative Systems,” Review, June 1979.

-.

On the other hand, mirror systems would ●

possess the following potential disadvantages:

● They would require a large number of sat-ellites each with individual attitude con- ●

trol. Maintenance might be expensive anddifficult to accomplish.

The mechanisms needed to keeprors pointed accurately might becated.

the mir-compli-

The mirrors might cause unwanted weath-er modifications around the ground sta-tions (see below and ch. 8).


●

●

●

Scattered light from the mirrors and thelight beams in the atmosphere would in-terfere with astronomical research (seech. 8).The large power production per site (10 to135 GW) and necessary centralization ofthe electrical supply from them would notbe attractive to the utilities (see ch. 9).The large area of the receiving sites (100to 1,000 km2) would be likely to makeland-based siting extremely difficult if notimpossible from a sociopolitical stand-point (see ch. 9).

The Mirror System

The “baseline” Mark 1 SOLARES54 design(table 9) would require a total mirror area ofnearly 46,000 km2. If each mirror were 50 km2,about 916 of them would be necessary for aglobal power system that would produce atotal of 810 GW from six individual sites, orabout twice 1980 U.S. electric generation. Itwas chosen for comparative purposes becauseit demonstrates the potential for large scaleenergy output that might be achieved with mir-rors. It is by no means the optimum SOLARESsystem. A low-orbit version (altitude 2,000 km)with 15 smaller ground stations (10,000 to13,000 MW output) might be more feasible ordesirable. One of the principal features of theSOLARES concept is that it could be used forany energy use where enhanced sunlight wouldbe used to advantage. By using many moresmaller mirrors, the mass per unit area couldbe minimized, and the total mass in orbit forthe entire baseline system then becomes about4X105 tonnes. Thus, the entire SOLARESbaseline system would require only the samemass in space as eight 5,000 MW reference sys-tem satellites.

Several Earth-based energy productionmethods currently under development mightbe used in conjunction with orbital reflectorsystems: 1 ) photovoltaic arrays of varying sizesare projected for commercial deployment inthe late 1980’s, and 2) solar-thermal electric

54 Billman, et al., “Solar Energy Economics Revisited. ThePromise and Challenge of Orbiting Reflector for World EnergySupply, ” op. cit

Table 9.—SOLARES Baseline System

configuration:Space system

4,146km inclined orbit, 45,800km2 total mirror areaGround system

6 sites with DOE 1986 goal solar cells @ 15% efficiency11 0/0 overall system conversion efficiency, ~~-circlearea = 1.168km2 each, 135 GWe each

Impact:Total system would produce 3.24 times current U.S. con-

sumption, total area = 84 x 84km2 (52 x 52 mi2)

Baselined costs (in 1977 dollars)Implementation schedule

5-year development, design, test, and evaluation (DDTE)2-year manufacturing and transport fleet facilities

preparation6-year space and ground hardware construction

System complete about 1995Direct costs estimate (billions of dollars)

Facilities . . . . . . . . . . . . . . . . . . . . ... ... ... ... ..$ 47.30Hardware. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 885.65

Total direct . . . . . . . . . . . . . . . . . . . . ... ... ... .$932.95Indirect costs estimate (billions of dollars)

15% contingency on direct costs ... ... ... ... .. $139.94Design, development, test, and evaluation . . . . . . 43.80Interest a:

Facilities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23.58Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101.26DDTE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41.01

Total indirect. . . . . . . . . . . . . . . . . . . . . ... .. .$349.59Total cost . . . . . . . . . . . . . . . . . . . . ... .. . $1,282.54

Indirect cost factor. . . . . . . . . . . . . . . . . . . . . . . . . . .....1.38Installed cost per rated output ($/kWe)b. . ...........1,508Capacity factor(%) . . . . . . . . . . . . . . . . . . . . . . . . . .......951995 O&M costs:

Fixed ($/kW-y). . . . . . . . . . . . . . . . . . . . . . . . . . . . ........3Variable (mills/kWh). . . . . . . . . . . . . . . . . . . . . . . ........2

Levelized capital cost (mil ls/kWh)C . .................27.2Levelized O&M cost (mills/kWh)d . . . . . . . . . . . . . . . . . . . . 4.5Levelized busbar energy cost (mills/kWh)e. . ..........31.6

Comparison baseload power systems (CIRCA 1995):Conventional coal/nuclear mixf

Levelized busbar energy cost (mills/kWh)e . . .......45Ambient sunlight photovoltaicf g

Levelized busbar energy cost (mills/kWh). . .......115a4Y@ first year, 8% per annum until positive cash flow after Year 11.blncludes all direct costs, 157” contingency, interest during implementation at

8% per annum.c15% fixed charge rate 30 years at 60/0 annual inflatiOn.d30 years at 6% annual’ inflation,e15y& fixed charge rate.fsee text; these d. not include their historically eXtenSive R&D costs that are

Included, in SOLARES costing.91Jses same terrestrial costing algorithm as SOLARES that results in indirect

cost factor of 1.37.

SOURCE: K. W. Billman, W. P. Gilbreath, and S. W. Bowen, “Solar Energy -Economics Revisited: The Promise and Challenge of OrbitingReflector for World Energy Supply,” DOE SPS Program Review,June 8, 1979.

plants should become commercially feasiblein selected locations about the same time, pos-sibly also for “repowering” of existing coal- oroil-fired fossil-fuel plants with solar boilers.Much of the economic disadvantage of bothtypes of solar-electric powerplants is associ-

Ch. 5—Alternative Systems for SPS Ž 89

ated with the energy storage needed to allowthem to serve as intermediate or baseloadplants. Should these plants prove to be evenmarginally successful, relieving their storageneeds by keeping them I it for 24 hours a day bysunlight from orbiting reflectors would en-hance the attractiveness of these terrestrial op-tions.

The various benefits of a mirror system mustbe weighed against the percentage of time theground-based energy production facilitieswould be obscured by clouds, smog, fog, andother atmospheric obstruct ions. However,there is some evidence” that the concentratedsunlight provided by the orbiting mirrorswould tend to disperse water-based obscura-tions such as clouds and fog, as a consequence

“Ibid

of the accelerated evaporation produced bythe high-intensity solar radiation.

If the orbiting mirrors can disperse clouds ofmoisture around the SOLARES ground station,what effects may they have on the climatenearby? Large orbiting mirrors have been sug-gested for use in climate modification,56 buttheir possible detrimental side effects have notbeen studied (see ch. 8). However, even ifreflected sunlight could be shown to have asalutary effect on certain regions of the Earth,there is no reason to believe, without furtherstudy, that regions whose weather patternscould benefit from enhanced sunlight wouldnecesssariIy coincide with the SOLARESground stations.

—*’I Bekey and J E Nagle, “Just Over the Horizon in Space,”

Astronaut/es and Aeronautics, May 1980.

SPACE TRANSPORTATION AND CONSTRUCTION ALTERNATIVES

Space transportation and construction (withthe possible exception of SOLARES) are com-mon to all the options. NASA contractors whodeveloped the transportation, construction,and assembly plan for the reference systemdevoted considerable effort to the processof winnowing out a host of alternative ap-proaches. Nevertheless, several other construc-tion/assembly schemes have been proposed forvarious phases of SPS program development.If feasible, they would mostly serve the pur-pose of reducing costs by using technologydeveloped for other programs or by reconfigur-ing the reference system scenario. Becausetransportation costs are a significant percent-age of any systems cost (see section on costsbelow), it would be important to explore thesealternatives fulIy.

Transportation

Transportation strategy in the early develop-ment phase and engineering verification is touse the shuttle or an upgraded shuttIe to theirmaximum capacities. In these, as well as laterdemonstration and production phases, using

shuttle size vehicles at high launch rates couldbe cheaper than developing and using largerlaunch vehicles (see section on costs). Perhapsthe most obvious approach is to upgrade theshuttle-based space transportation system toperhaps five times the capability (i.e., totalmass to space in a given time as represented bypayload size, launch rate, and turn-around) ofthe present shuttle.57

The need to conduct relatively sizable ex-periments, and possibly prototype or demon-stration projects in geostationary orbits ratherthan in low-Earth orbits, would pose a serioustransportation problem. Current space-shuttleupper stages, or “orbital transfer vehicles, ” arenot capable of carrying large payloads to geo-stationary orbit and are not able to supportany servicing operations there, since theseunits are not reusable.

Several innovative approaches have beensuggested that circumvent the need for devel-oping new vehicles. One such approach em-ploy; an in-orbit propel

‘7 Salkeld, et al,, op. cit.

ant processing facility

83-316 0 - 81 - 7


built into one of the shuttle’s big “throwaway”propellant tanks to convert water into hydro-gen and oxygen –the best propellants for high-performance rocket engines. The water re-quired as the feedstock for this process wouldbe carried into LEO as an “offload” on everyspace shuttle flight whose payload is less thanthe maximum shuttle capability. The hydrogenand oxygen, after being liquefied and stored inthe propellant processing facility’s tank, arethen used as the propellants for a reusable low-thrust “space tug” whose principal componentis also a leftover shuttle propellant tank. Thetug, which replaces the cargo orbital transfervehicle of the reference system, would carrySPS prototype or demonstration hardware upto CEO. Although such a system is rather com-pletely defined,58 considerable technology ad-vancement and development would be re-quired, e.g., for the in-orbit electrolysis andliquefaction plants, the space-tug-develop-ment, and the system logistics and integration.Cost estimates have not yet been released.Nevertheless, this concept represents an in-teresting suggestion for eliminating the de-velopment of a major new (or upgraded)launch vehicle just for an SPS demonstration,thereby reducing the “up-front” costs of anysizable SPS prototype or demonstration proj-ect.

Another scheme would use an electro-magnetic propulsion device59 called a “massdriver” to provide orbital transfer thrust in-stead of the chemical-rocket-powered spacetug. The mass driver is simply a solar-poweredlinear electric motor, which derives its thrustby accelerating chunks of waste mass (e.g.,chopped-up or powdered shuttle propellanttanks) into space at high exhaust velocities. 60 61

Since it uses electricity, its energy could comedirectly from the Sun via photoelectric conver-

58 Central Dynamics Corp (Convair Dlvlslon), “Utilization ofShuttle External Tank in Space, ” unpublished presentation, j une1978.

5~F, Chiiton, B, H ibbs, H. Kolm, G K O’Neill, and J. phil lips,“Electromagnetic Mass Drivers,” in “Space-Based Manufactur-ing From Nonterrestrial Material s,” G K C)’Neil I (cd.), Progress inAstronautics and Aeronautics, vol. 57 (New York AlAA, August1977), pp. 37-61.

bochllton, et a]., “Mass-Driver Application s,” ibid , PP. 63-94.“Gerard K O’Neill, “The Low (Profile) Road to Space Manu-

facturing,” Astronautics & Aeronautics, March 1978, pp. 24-32.

sion. This concept is far more ambitious thanthe in-space propellant processing scheme; fur-thermore, it depends on a device that, al-though tested extensively on Earth in experi-mental high-speed trains and in the laboratory,has yet to be demonstrated at the scale and ac-celeration levels required by the orbital trans-fer application. A modest research effort onthis concept is currently being supported byNASA’s Office of Aeronautics and Space Tech-nology.

The production phase of the SPS programwould present a number of opportunities fortransportation alternatives that could not onlyreduce production costs, but could also miti-gate environmental and other impacts. Be-cause of the high proportion of total space seg-ment construction costs (both nonrecurringand recurring) taken up by transportation,many of the proposed innovations center onalternatives to the family of four transporta-tion vehicles selected for the reference system.

The most direct approach to transportationcost reduction would be to improve the HLLV,since it absorbs the bulk of transportationdevelopment and operations costs. The mostlikely technological alternative appears to bethe use of fully reusable single-stage-to-orbit(SSTO) vehicles. 62 Very advanced wingedSSTO vehicles that could reduce LEO payloaddelivery costs to the order of $1 5/km are pro-jected as becoming practical in the last decadeof this century, provided sufficient demandexists. 63

For orbital transfer the personnel and cargoorbital transfer vehicles selected for thereference system probably represent the bestavailable technology in the two principal op-tions: chemical and electric propulsion.

Alternatives for routine high-mass payloadhauling might include solar sails, laser propul-sion, and various forms of electric propulsionother than the ion (electrostatic) rocket de-scribed for the reference system, e.g., elec-

62 Beverly Z. Henry and Charles H Eldred, “Advanced Technol-ogy and Future Earth-Orbit Transportation System s,” in Space

Manu(actur;ng Facilities //, jerry Grey (ed ) (New York: Al AA,Sept 1, 1977), pp 43-51

“lbld


tromagnetic (plasma) thrusters or the massdriver discussed above. None of these optionshas been studied in enough detail to makechoices about them at the present time.

Space Construction

As currently designed, the space componentof the reference system would be constructedin CEO. However, it may be more cost effec-tive to build the necessary facilities andsatellites in LEO and transport them to CEOfully constructed. Such a scenario would re-duce the number of personnel needed in CEOas well as lower the total mass that must betransported there.

Introducing one of the LEO scenarios (i. e.,laser or mirrors) would open up significantchanges in the construction and transportationoption for the SPS. Even a change in one majorcomponent of the reference system satellitecould alter the ways in which the transporta-tion and construction components are con-figured. For example, if the photovoltaic cellswere to be replaced by solar thermal conver-sion systems, it would be attractive to con-struct satellites in LEO and transport them toCEO on their own power because they wouldsuffer less from passage through the Van Allenradiation belts.

Of all the alternative options for SPS con-struction in the production phase, the prospec-tive use of nonterrestrial materials is perhapsthe most innovative and, ultimately, capableof the maximum potential return on invest-ment.

The basic premise of the nonterrestrial ma-terials option is that the cost, energy and mate-rials requirements, and environmental impactof lifting the enormous cumulative massesneeded to establish and operate a system ofmany satellite power stations off the Earth canbe markedly reduced by utilizing first lunarmaterials, and eventually materials obtainedfrom asteroids. The fundamental physical prin-ciple that supports this premise is that it takesover 20 times as much energy to launch an ob-ject to geostationary orbit from the Earth as itdoes from the Moon, and the situation for as-

teroidal materials could be even more favor-able. The primary drawback is the high “up-front” cost of establishing the necessary min-ing base on the Moon and the space-based fa-cility needed to construct and assemble theSPS. Hence, it is not likely that nonterrestrialmaterials would be used in the prototype,demonstration, or even the early phases of SPSproduction. However, if a commitment ismade to produce a large-scale SPS system inCEO, the lunar materials supply option couldwell be less expensive than the Earth-launchedoption (including payback of the initial invest-merit) . 64 It has been argued that by “bootstrap-ping” the operation (i. e., using nonterrestrialmaterial right from the beginning, not only tobuild the SPS but to build all the necessaryfacilities as well), there is no need for any newlaunch-vehicle development (a major elementin the “up-front” investment); i.e., the presentspace shuttle can provide all the Earth-launchspace transportation needed to implement anoperational multi-SPS network. 65

Decisions on the nonterrestrial materials op-tion clearly hinge on the results of current andprojected SPS technology studies and experi-ments. Sufficient research on the two techno-logical factors unique to nonterrestrial materi-als development—the mass driver (both forlunar materials transfer and for in-space pro-pulsion) and lunar materials mining and proc-essing capability —should be done so that adecision to proceed with either the Earth ornonterrestrial materials options could be prop-erly made. Other study and research require-ments for the nonterrestrial materials optioninclude system analyses (including design ofan SPS that maximizes the use of lunar materi-als), more intensive searches for appropriateEarth-approaching asteroids, and establishingcapabilities for the host of space operationalfunctions needed for other space programs.

As is clear from the preceding discussion, itis difficult to establish a priori alternatives toconstruction, assembly, and transportation,

“Davld L Akin, “Optimization of Space Manufacturing Sys-terns, ” in Space Manufacturing ///, Jerry Grey and Christine Krop(eds ) (New York. AlAA, November 1979)

b50’Nelll, op cit


since each of the SPS alternative optionswould call for a different approach. Generalguidelines can be identified, minimizingtransportation and construction costs duringthe evaluation, development, prototype, anddemonstration phases by: 1) utilizing a phased,step-by-step approach (e. g., ground-based ex-periments, only then followed by dedicatedspace experiments); 2) maximizing use of the

essentially developed space shuttle; 3) max-imizing the common utilization of technologyand development efforts by other programshaving related requirements (e.g., large com-munications antennas and other large spacestructures, spacecraft power generation, con-trol and transmission, etc.); and 4) developingnew transportation vehicles and constructionhardware only when economically necessary.

SPS COSTS

Although knowledge of the overall costs ofan SPS program will be essential to making adecision about developing the SPS, currentcost estimates are inadequate. Today’s projec-tions are based on extrapolations from currenttechnology and in most cases assume majoradvances. Thus, the technical uncertainties ofthe concept are too great to provide a firmbasis for economic analyses. Here, as in mostother areas, it is only possible to develop thefoundation for future analysis that would seekto reduce the current uncertainties.

Reference System Costs

The most detailed cost estimates have beenmade by NASA66 for the reference system (fig.23). According to these estimates, which arebased on detailed hardware specifications andassociated transportation and industrial in-f restructure, achieving the first completereference system satellite will require an in-vestment of $102.4 billion over a 20-yearperiod. Figure 24 illustrates one estimate67 ofhow the costs could be allocated over time.Each additional copy of the satellite and asso-ciated terrestrial facilities would cost $11.3billion. Expenses are divided into the followingphases:

● Research — $370 million. This phase of SPSdevelopment (table 10) is by far the small-est, constituting less than 0.4 percent ofthe total SPS program. About half of these

bbPiland, op. cit.“Woodcock, “Solar Power Satellite System Definition Study,”

op. cit.

Figure 23.—Reference System Costs(dollars in billions)a

aNASA estimates—1977 dollars.

SOURCE: National Aeronautics and Space Administration


Figure 24.— How Cost Could Be Allocated

o

Years

SOURCE: National Aeronautics and Space Administration.

Table 10.—Research—$37O Million

Millions Percentof dollars of total

Power generation . . . . . . . . . . . . . . $ 79 21Power transmission . . . . . . . . . . . . 40 11Structures and control. . . . . . . . . . 22 6Space construction . . . . . . . . . . . . 25 7Space transportation . . . . . . . . . . . 20 5System studies. . . . . . . . . . . . . . . . 19 5Research flight test . . . . . . . . . . . . 165 45

$370


●

●

costs are chargeable to the developmentof the transportation system.Engineering–$8 billion. This part of theprogram (table 11) contributes the com-plex engineering knowledge necessary forcreating a useful space structure. Thework includes developing an engineeringtest article in LEO, capable of generating1 MW of power. It is the direct precursorto the demonstrator and provides the test-ing ground for constructing and using col-lector and transmitting subarrays, a rotaryjoint and satellite attitude control.Demonstration –$23 billion. This phase ofthe reference program (table 12) culmi-nates in a 300-MW satellite and the asso-

Table 11 .—Engineering—$8 Billion—


SPS. . . . . . . . . . . . . . . . . . . . . . . . . .Test article hardware . . . . . . . . . . .LEO base (8 man) . . . . . . . . . . . . . .Manned orbital transfer vehicle. . .Shuttle flights. . . . . . . . . . . . . . . . .Shuttle booster. . . . . . . . . . . . . . . .Management and integration . . . .

Total. . . . . . . . . . . . . . . . . . . . . . .

$ 370 5210 3

2,400 301,200 15

870 112,900 36

61 1

$8,000

NOTE: Percentages do not total 100% due to rounding errors.


Table 12.—Demonstration—$23 Billion


Demonstrator:DDT&E . . . . . . . . . . . . . . . . . . . . . $2,700Hardware. . . . . . . . . . . . . . . . . . . 2,500

Pilot production facilities . . . . . . . 400Shuttle DDT&E and fleet . . . . . . . . 3,000Construction:

DDT&E . . . . . . . . . . . . . . . . . . . . . 3,100Hardware. . . . . . . . . . . . . . . . . . . 3,000

Space operations (4 yearsoperations, construct bases,and demonstrations) . . . . . . . . . 2,800

Personnel orbital transfer vehicle(DDT&E and hardware). . . . . . . . 1,700

Electric orbital transfer vehicle(DDT&E) . . . . . . . . . . . . . . . . . . . . 1,800

Demonstration rectenna . . . . . . . . 1,800Management and integration . . . . 200

1211

213

1313

12

7

881

Total. . . . . . . . . . . . . . . . . . . . . $23,000


●

ciated rectenna and ground facilities tocollect and disperse electrical power tothe grid. The demonstrator requires a sec-ond generation shuttle and orbital trans-fer vehicle to provide the transportationcapabiIity to GEO.Investment—$57.9 billion. By far thelargest percentage (57 percent) of the non-recurring costs of the reference system aredevoted to this phase (table 13). In addi-tion to providing for the transportationand construction capabilities for thespace component, it also includes thecosts ($7.8 bill ion) for developing the ter-restrial factories needed to produce satel-lite components.


Table 13.—SPS lnvestment—$57.9 Billion

Millions of Percentdollars of total

Heavy lift launch vehicle . . . . . . . . $16,600 29Development. ... ... ... ... .. .$10,500 18%Fleet (6 boosters, 7 orbiters) ... $ 6,100 11 0/0

Electric orbital transferVehicle (21 x 284). . . . . . . . . . . . . 6,000

Construction bases . . . . . . . . . . . . 17,200 30Development. ... ... ... ... ... $ 4,300 8 %

Hardware and launch ... ... .. .$12,900 22%.SPS development . . . . . . . . . . . . . . 2,200 4Ground-based factories(klystrons, solar cells, etc.) . . . . . 7,800 13

Launch and recovery sites. . . . . . . 7,300 13Program management andintegration. . . . . . . . . . . . . . . . . . . 800 1Total. . . . . . . . . . . . . . . . . . . . . . . $57,900


Though these are the best estimates currentlyavailable, they suffer from an unavoidablelack of specific engineering details, as well asfrom insufficient manufacturing experiencefor most of the system components. Moreover,in some areas, (e. g., klystrons, slip ring, phasecontrol) current technology is inadequate todefine solutions to engineering problems.Thus, the estimates could eventually turn outto be high or low. The DOE SPS Cost Review68

examined five different elements of the SPSreference design and concluded that the pro-jected costs are “based on optimistic assess-ments of future technological and manufac-turing capabilities. ”

●

●

Rectenna support construction. Projectedcosts were found to be low by a factor of3 to 5. Automated production mightreduce costs to a level more in keepingwith the reference system estimates, butsignificant advances over today’s meth-ods would be needed.Graphite fiber-reinforced thermoplastic.Currently used for golf clubs, fishing rods,and for any other use where low weightand high stiffness are required, this is therecommended material for the satellitetruss work. The proposed structures areinsufficiently defined to specify the costs.Estimates of future costs for the materials

‘*J. H. Crowley and E J. Ziegler, “Satellite Power Sy5tems (SPS)Cost Review,” DOE/TIC-11190, MaV 1980

●

●

●

alone vary by a factor of 30 ($40 to$1 ,250/kg).Photovoltaic cells. GaAs cell cost esti-mates are extremely optimistic given thecurrent state of technology. Break-throughs will be needed to reach thedesign goals for mass, efficiency, andcosts. Silicon cell cost estimates are lessoptimistic but will still require significantsimultaneous reductions in mass and costand an increase in efficiency to achievethe SPS goal (2 g/W, $0.17/Wp, and 17-percent efficiency).Slip ring. It is not well enough defined toappraise the slip ring components or theiroperational capabiIity.Satellite electrical systems. The degree ofdetail is insufficient to judge the credibili-ty of the cost estimates of the subsystem.

Thus, the $102.4 billion estimate of “frontend” costs and the $11.3 billion estimates foreach satellite may be an optimistic estimate ofSPS costs.

On the other hand, if unexpected break-throughs were to occur in space transporta-tion, rectenna or satellite technology, the costsof the reference system could be lower thannow estimated. Since NASA estimates alreadyassume some technological breakthroughs(e.g., in solar cell production, space construc-tion, rectenna construction), they are morelikely to be low than high. In either case, theestimates reflect a troublesome feature of thereference system —the high costs that are nec-essary to demonstrate the feasibility of the SPS(about $31 billion). A further $71 billion wouldbe needed to build and use a single referencesystem satellite (investment of $57.9 billionand a first satellite costing $13.1 billion).Because the initial costs have a direct bearingon financing the project, they are more fullydiscussed in chapter 9.

A number of opportunities exist for reducingSPS development expenses. Some involve pur-suing alternative concepts; others, revising thereference system. Because the reference sys-tem is by no means an optimal design, im-provements could lead to significant costreductions. Common to all potential systems


would be the division of SPS development intothe phases outlined above: research, engineer-ing verification, demonstration, and invest-ment, with increasing commitment of re-sources in each successive phase. For micro-wave and laser systems, space transportationand construction would constitute a high per-centage of the system costs in all phases. It isin these areas that there would be a highpotential for reducing overall costs.

The precise costs of an SPS program wouldalso depend strongly on the nature and scopeof national and global interest in space. Ifcommercial ventures in space grow at a strongenough rate (e. g., for telecommunications sat-ellites, space manufacturing, etc.), the currentshuttle and its related technology would be in-adequate, and pressures would be strong fordeveloping expanded space capabilities. Theexplosive growth of the domestic airline in-dustry since the 1930’s has been suggested asthe appropriate model to use to investigatethis eventuality. 69

Much of the technology and experienceneeded for space construction (manned LEOand GEO bases, large-scale antennas, studiesof space productivity, etc. ) and space transpor-tation (manned and unmanned orbital-transfervehicles, shuttIe boosters, HLLVS, etc.) of SPSwould be developed for other programs aswell. Of these, the SPS program should bearonly its share. By charging only those coststhat are unique to SPS to the SPS program, itsfront end costs would be reduced by a signifi-cant amount. Seen in this light, the massivespace capability needed for mounting an SPSprogram would be less of an anomaly (giventhe future evolution of space technology), ’”and SPS would need to shoulder fewer of thedevelopment costs for this capability.

There is also the possibility that a percent-age of the investment phase could be shoul-dered by private investment, thereby reducingthe burden to taxpayers. This would be all themore likely to happen in a milieu in which

“C, R. Woodcock, “Solar Power Satellites and the Evolutionof Space Technology, “ AIAA Annual Meeting, May 1980.

701 bid.

private investment in space is strong for otherreasons. Under these combined circumstances,the total risk to the U.S. taxpayer would besubstantialIy reduced.

One interesting option for reducing trans-portation costs of a CEO SPS would be toassemble the satellite in LEO and send it toCEO under its own power. This might beparticularly applicable to the demonstrationphase of the reference program, since it wouldavoid the need for premature investment in anexpensive manned geosynchronous construc-tion/assembly facility.

Whatever their potential savings, all of thesepossibilities could only be evaluated after theproper scale of a demonstration satellite hadbeen determined. This decision, in turn, woulddepend on considerable terrestrial and space-based testing, some of which will take place inother space programs (see ch. 5).

Because the HLLV would be used later on inthe production phase of the reference SPS ab-sorbs the bulk of transportation costs, it is ofconsiderable interest to find less expensiveways of transporting mass to space. Some ofthe alternative high-capacity transportationvehicles have been discussed earlier in thischapter. The heavy Iift launch vehicles achievetheir cost reductions by economies of scale. Ithas been suggested that smaller vehicles,perhaps only slightly larger than the currentspace shuttle, could be used instead of themuch larger HLLV.71 The smaller vehicleswould use higher launch frequencies toachieve the same or better benefits. Accordingto this proposal, the minimum-cost individualpayload necessary to launch as many as fivereference SPS satellites to orbit is about 50tonnes (compared to the Shuttle’s 30 tonnes).The prospects for employing routine airline-Iike launch practices opens a whole new ap-proach to the logistics of major space manu-facturing enterprises as well as providingpotential cost reductions for SPS.

“R. H Miller and D. L. Akin, “Logistics Costs of Solar PowerSatellites,” Space So/ar Power Review, VOI 1, pp. 191-208,1980.


ALTERNATIVE SYSTEMS

Systems other than the reference systemmight be more or less costly, depending on fac-tors such as the achievable efficiency, themass in orbit, and the state of development ofthe alternative technologies that make upthese systems. At present, these alternativesare much less defined and their costs accord-ingly even more uncertain than the referencesystem costs. The following discussion summa-rizes available cost data and the greatest costuncertainties of the alternative systems.

●

●

●

The Solid-State System

The unit cost of the solid-state devices is un-known. However, the semiconductor indus-try has considerable experience in producinglarge numbers of reliable solid-state com-ponents at low cost, and the learning curvefor such production is well-known. In princi-ple, it should be possible to make a realisticprediction of costs when the appropriate de-vice or devices are well characterized.Solid-state efficiencies. Present efficienciesare much lower than for the klystron. Cur-rent research is aimed at increasing theiroperating efficiency (to reach at least 85 per-cent).Mass in space. Current estimates of the massper kilowatt of delivered power72 suggestthat the mass in space would be higher thanthat of the reference system making thetransportation costs higher as well.

Since many components of the solid-statesystem are shared with the reference system(e.g., the graphite fiber reinforced thermo-plastic support structures, the photovoltaic ar-rays, the rectenna design, etc.), it would bepossible to generate realistic relative costs ifthe above uncertainties are reduced.

7*G. Hanley, “Satellite Power Systems (SPS) Concept Defini-tion Study,” vol. 1, Rockwell International SSD-8O-O1O8-I, Oc-tober 1980.

The Laser System

The largest unknowns for the laser systemare the efficiency, specific mass and the costof the transmitting lasers themselves. This isbecause the technology of high-power CWlasers is in a relatively primitive state (currentCW lasers achieve outputs of 20 kw or greater,operated in a so-called loop move, i.e., theIasant is recirculated). Space lasers for SPSwould have to operate at much higher outputs(megawatts) and at higher efficiencies (i.e., 50v. 20 percent) for current lasers. Concepts suchas the solar pumped laser and the free electronlaser are completely untried in a form thatwould be appropriate to SPS. Therefore theircosts are even more difficult to ascertain. Ingeneral it can be said that the cost of thesystem would be tied to the overall efficiencyof the system and the amount of mass inspace, but considerable study and some devel-opment would be needed to make suitablyreliable projections.

●

●

●

Transportation. The laser systems that havebeen explored project higher mass in orbitthan for the reference system, which maydrive the cost of the laser system up. How-ever, if a substantial portion of this mass isin LEO rather than in CEO, the overall trans-portation costs might not exceed the trans-portation costs of the reference system andcould turn out to be lower.

Demonstration. Because the laser system isintrinsically smaller it should be possible tomount a demonstration project for consid-erably less than for the reference system.

Terrestrial component. The ground stationswould have to have a certain amount of re-dundancy in order to accommodate lasertransmission when cloudy weather obscuresone or more receivers. The precise amountof redundancy would depend on the particu-lar location and would include extra trans-mission lines as well as extra groundreceivers.


The Mirror System

Figure 25 summarizes mirror system costestimates for the SOLARES baseline case 73

based on the DOE 1986 cost goals for photo-voltaic cells. These “up front” cost estimates,which include contingency and interest on theborrowed money, lead to an estimated level-ized busbar energy cost of 31 mills/kWehrcompared to 1990 estimated costs of nuclear/coal mix of 45 mills/kWehr. I n comparison, astrictly terrestrial system of photovoltaics pro-

7 3 et “Solar Energy Economics Revisited: ThePromise and Challenge of orbiting Reflector for World EnergySupply, ” cit.

ducing the same overall output computed onidentical assumptions would cost 115m i I Is/k Wehr.

Since electricity production from the mirrorsystem would depend heavily on the use of ter-restrial solar photovoltaic or solar thermalsystems, cost variations of either conversionsystem would have a strong effect on totalsystem costs. Figure 26 summarizes the effectof varying several system parameters on thecost of electricity delivered to the busbar inthe SOLARES system. The three most sensitiveparameters are solar cell efficiency, solar cellcost per peak kilowatt and total space cost

Figure 25.—Elements and Costs, in 1977 Dollars, for the Baseline (photovoltaicconversion, 4,146 km, inclined orbit) SOLARES System

Solar cells

NOTE: Total costs are proportional to the areas of the circles. Interest and contingency constitute 33 percent of the total SOLARES costs.SOURCE: K. W. Billman, W. P. Gilbreath, and S. W. Bowen, “Space Reflector Technology and Its System Implications” AlAA paper 79-0545,

AIAA 15th Annual Meeting and Technical Display, 1979.


Figure 26.—Sensitivity of the SOLARES MirrorSystem to Variations in System Parameters

% Variation of parameters

(transport, construction, mirrors in space). Acost over-run of about 2 times (to $1,000/pkkWe) could be tolerated before a busbar costof 45 milis/kWehr wouId be reached. Similarly,a space system total cost over-run of a factorof 4.25 could be tolerated. Finally, because ofthe projected high energy production per unitof mirror mass in space, a twenty-three-fold in-crease in space transport cost (or $1 ,380/kg)would still result in a production cost of 45mills/kWehr. For comparison, the charge fortransporting mass to space by means of thespace shuttle is estimated to be between $84and $154 (1975 dollars). ”

74 National Aeronautics and Space Administration, “SpaceTransportation Reimbursement Guide,” JSC-11-802, May 1980

SOURCE: Ken Billman, W. P. Gilbreath, and S. W. Bower, “Space ReflectorTechnology and Its System Implications” AlAA paper 79-0545 AlAA15th Annual Meeting and Technical Display, 1979,

Chapter 6

SPS IN CONTEXT

ContentsPage

Energy. . . . . . . . . . . . . . . . . . . . . . .......101Introduction . . . . . . . . . . . . . . . . . . . . .. 101Overview . . . . . . . . . . . . . . . .......,101Determinants of Demand. . ..........102Energy Supply Comparisons . . . . . . . ...104Implications. . . . . . . . . . . . . . . . . . . . . .131

The Effects of SPS on Civilian SpacePoilcy and Programs . . . . . . . . . . . .135

Space Pol icy. . . . . . . . . . . . . . . . . . . . . .135Current and Projected Space Projects. . .137Institutional Structures. . ............139indirect Effects and ’’Spinoffs”. . ......139

LIST OF TABLES

Table No. Page14. Criteria for Choice, , . ..............10515. Characteristics of Five Electrical

T e c h n o l o g i e s . . . . . . . . . . . . . . . . . . . . . 1 1 0

Table No. Page

16.

17.18.19.

20.

21.22.23.

Description of Milestones of MajorBreeder Programs . . . . . . . . . . . . . . . . .116Summary Assessment. . . . . . . . . . . . , .125Major Environmental Risks. . ........127Terrestrial and Space InsolationCompared. . . . . . . . . . . . . . . . . . . . . . .128Terrestrial Insolation at DifferentLatitudes and Climates . ............129Costs of Onsite Photovltaics. . ......131Range of Energy Demand in 2030,....132Upper Range of SPS Use . ..,........135

LIST OF FIGURES

Figure No. Page27 Recent and Projected Solar

Photovoitaic Prices. ., . . . + . . . . . . ...11428 Levelized Lifecyle Cost of Electricity ..12429 Quarttified Health Effects. . .........126

Chapter 6

SPS IN CONTEXT

ENERGY

Introduction

Because of its long development Ieadtime,solar power satellites (SPS) will not be avail-able to any extent before the early part of thenext century and will therefore do very little torelieve our dependence on imported oil. SPS’sprimary use would be to replace old power-plants and meet any new demand for elec-tricity. Consequently, the potential value ofthe SPS must be determined in competitionwith other future electricity sources and in thecontext of U.S. and global electricity demand.This chapter examines this topic in detail bylooking at the future demand for energy, andelectric power in particular, in the UnitedStates, and the various supply options thatcould compete with the SPS. Global energy de-mand and the SPS in a worldwide context is ex-amined in chapter 7.

Overview

The U.S. energy future can be divided intothree time periods according to the supply op-tions that will be available. These periods areroughly the next 10 years (near term), from1990 to approximately 2020 (the midterm ortransition period), and beyond 2020 (the longterm). Although these boundaries are not hardand fast, they roughly define periods in whichparticular energy supply forms will dominate.

Near Term

In the near term, there will be no significantchange from our current reliance on oil, natu-ral gas, and coal. Currently about 92 percent ofour Nation’s energy supply comes from thesefuels. About one-quarter of the total is im-ported (almost all in the form of oil). Becauseof finite suppIies, overalI consumption of theseliquid and gaseous fossil fuels must eventuallybe reduced. However, the most important goalover the next decade is the reduction of oil im-ports in order to avoid the severe economic

problems that would result from potential sup-ply interruptions and to improve the U.S. tradedeficit. To do this, concentration must beplaced on lowering demand growth by increas-ing the efficiency of energy use, and switchingto the use of more abundant domestic fuels.Of the two, improving energy efficiency will bethe major new source of energy because of themuch longer Ieadtime needed to bring on newfuel supplies such as coal and nuclear. Do-mestic oil and natural gas can be developedmore quickly, but it is not likely that they willcontribute to reducing oil imports since bothwill probably decline in production for thedecade. A recent OTA technical memoran-dum’ estimates a 25-to 45-percent drop in U.S.oil production by 1990. Thte use of nuclearenergy will increase, but at a slower rate thanin the 1970’s. Finally, solar and biomass energyproduction will grow rapidly during the 1980’sbut the absolute magnitude will be low com-pared to oil imports. Therefore, although an in-crease in the amount of coal, solar, biomass,and possibly nuclear energy sources is ex-pected, they will probably not be able to con-tribute enough by themselves to relieve thepressures caused by U.S. dependence on im-ports.

Transition Period: Midterm

In the period from 1990 to 2020, substantialsupply shifts will occur. Although the periodwill begin with heavy dependence on coal, oil,and natural gas, it will end with a much greaterreliance on renewable and inexhaustible ener-gy resources. U.S. dependence on imported oilwill almost surely come to an end if for noother reason than that the availability of oil onthe world market will have dropped substan-tially. World oil production may drop as muchas 20 percent by 2000 and fall off sharplythereafter. The dominant fuels during this

‘Office of Technology Assessment, U.S. Congress, “WorldPetroleum Availability, 1980-2000,” technical memorandum, Oc-tober 1980, OTA-T M-E-5

101


period are likely to be coal (for synthetic fuels,direct combustion, and electricity generation),natural gas, and possibly conventional nu-clear. During this period, strong growth of re-newable and inexhaustible sources such assolar and biomass can be expected. Uranium isa small enough resource that conventionalnuclear must be considered a transition energysource. However, the supply of coal appears tobe substantial enough to play a major role wellinto the 22d century. Whether these fuels con-tribute significantly beyond the midterm de-pends on the successful resolution of theirshort- and long-term environmental and safetyquestions.

It is also during this period that SPS andother long-term candidates such as breeder re-actors and perhaps fusion may begin to reachcommercial status. The transition period willbe the time when a number of long-term tech-nologies will compete with one another for arole in the future on the basis of economicsand public acceptance. This competition willalso depend heavily on the relative economicefficiency of different ways of using energy, aswill be discussed below.

Long Term

In the long term, the United States and theworld will be almost totally fueled by in-exhaustible energy sources. Although rapidgrowth of sources such as the SPS during thefirst decades of the century may be seen, it willnot be until the middle of the next century thatthey could become as commonplace as coal,electric, or even nuclear plants are today.

It is not clear which renewable and in-exhaustible sources will dominate. It may bethat small-scale, onsite solar systems coupledwith an extremely energy-efficient economywill be the ultimate future. It may also be thata mix of technologies such as onsite solar,biomass, fusion and/or SPS will be used.However, the choice will be made in the transi-tion period and will be based primarily on theprojected costs of competing supply systemsand demand technologies.

Determinants of Demand

SPS would fit most easily into a high electricgrowth future. Such a future is contrary to re-cent low growth trends. In fact, many conser-vation initiatives have been directed at reduc-ing the use of electricity because of the highenergy losses at powerplants. Nevertheless,changes in relative fuel prices and gains in theefficiency of electric generation and use coulddramatically change the picture.

The energy technology choices the UnitedStates and the world will make in movingthrough the three periods described above willbe primarily dictated, as always, by relativecosts. Until recently the dominant factor deter-mining the development of energy tech-nologies has been the type of resource and itsavailability. The abundance of oil and naturalgas, and the ease with which it could betransported and burned, dictated the de-velopment of most of the energy-using equip-ment currently in existence. Some of thisequipment could have been powered more ef-ficiently by electricity, but this advantage wasoften dwarfed by the cost advantage thesefuels had over electricity. However, many ap-plications such as electric motors can be madesignificantly more efficient, reducing the fixedcost penalty.

In the past few years the relative prices ofthese energy forms have changed because ofthe rapid increase in oil and natural gas prices.Current average electricity prices are abouttwice that of oil and four times that of naturalgas. In 1960, the ratio of electricity to oil andnatural gas prices was 7 to 1. Even though thecosts of new powerplants are rising rapidly,those of electricity will probably rise moreslowly than oil and natural gas, primarilybecause of the relative abundance of coal anduranium. It is even possible that synthetic fuelsfrom coal and biomass may be more expensivethan electricity from coal, particularly asnewer, more efficient coal combustion tech-nologies are introduced.

The total cost to the energy user also in-cludes the cost of the energy consuming equip-

Ch. 6—SPS in Context ● 103

ment. Electric powered equipment is oftencheaper than gas or oil fired counter parts.This advantage will become increasingly im-portant as the prices of oil and gas narrow thegap with the price of electricity.

The implication of these effects is that elec-tricity may become the cheapest energy form,when both supply and demand are considered,for many applications that could use a multi-plicity of energy forms. The reason is that theprice differential between electricity and theother energy forms (liquid and gaseous fuels,direct solar, etc.) will likely be small enoughthat it could be overcome by cheaper andmore efficient electric end-use technologies.Some of these, such as heat pumps for spaceand water heating, are already in use, whileothers, such as inexpensive electrochemicalprocesses and long-life storage batteries, re-quire further development, [f such develop-ment is successful and electricity does becomethe cheapest energy form for most uses, thenelectric demand growth could become quiterapid even though total energy demand maygrow very slowly or not at all.

If this holds, solar power satellites will havean easier market to penetrate than if the elec-tric utilities continue their recent slow growth.Thus, the fate of SPS rests as much on the abili-ty to create energy efficient electrical end-usetechnologies as it does on the relative eco-nomics of other electric generating technol-ogies. One caveat must be added, however. Ifdemand technologies for fuels keep pace withthe efficiency improvements of electric de-mand technologies, such dramatic switching

may not occur.

Electric Demand Technologies

To see if such a future is technically possiblea closer look is taken at current and potentialuses of electricity. Because of electricity’sunique properties it has been used forspecialized tasks such as lighting because ofthe high temperature needed to excite the visi-ble spectrum. Here, electrical energy is con-verted to visible electromagnetic radiation aswell as to heat. Nearly 60 percent of all elec-tricity is used to perform mechanical work

through the use of motors. Electricity is alsoused for industrial electrochemical processessuch as in aluminum and steel production, forspecialized induction-heating applications andfor microwave and infrared furnaces. A smallbut crucial amount is used to power the Na-tion’s electronic systems. Finally, electricity isused in the crudest form possible, namely fordirect conversion to heat.

Although these uses are more varied than forthe other major fuels, they account for lessthan 12 percent of the total end-use energy de-mand in this country. The other 88 plus percentis direct combustion to provide direct heat,steam and mechanical drive. As indicated, forelectricity to penetrate this latter market it willbe necessary to make technical advances togive electricity a cost advantage at the end-usethat can compensate for its higher cost at theproduction point.

To do this requires making use of the specialcharacter of electricity as an energy form.Electricity is a high-quality fuel (thermo-dynamically work that is heat at infinite tem-perature). Therefore, it can be used for anykind of mechanical work or it can be con-verted to heat at any temperature. The bestknown example of the latter property is theheat pump for space heating. This is now beingapplied to water heating and certain drying ap-plications with a substantial reduction inenergy use over electric resistance heating andapparent cost advantages over solar.

In the industrial area, there is considerablepotential for increased use of electricity. Forinstance, in steel making it can be used for theplasma-arc process and direct-electrolytic re-duction of iron. Although these processes havebeen arourd for several years, technical de-velopment is still needed. In a nearer term ap-plication, the direct reheating of steel by high,pulsed electric currents could result in a sig-nificant reduction in fuel use compared todirect-fired processes, and also reduce mate-rial loss by eliminating oxide formation thatoccurs with direct firing. In other areas ad-vances have been seen recently in the efficien-cy of electric motors that are now competitivewith steam drives in many applications such as


mechanical presses for metal forging. A morespeculative but very interesting area is the useof laser or microwave radiation to drive in-dustrial chemical reactions, instead of heat.

In ground transportation the principal prob-lem is the development of long-lived, light-weight, reliable storage batteries. EIectricdrive using motors with precise solid-statespeed control can be made very efficient, ashas been demonstrated on many of the world’srailroads. Advances have recently been madein battery technology but the general feeling isthat “ideal” batteries are at least a decadeaway.

The industrial sector is presently only 13-percent electrified, while the transportationsector only uses a negligible amount of elec-tricity. Thus, these are the markets that elec-tricity must penetrate to become the dominantenergy form. However, some new technologieshave the potential to reduce industrial de-mands without creating new markets for elec-tricity. In the chemical industry, for instance,biogenetic methods of feedstock synthesiscould replace thermochemical methods, re-ducing fuel usage without substituting elec-tricity. About half the present industrial elec-tric demand could be offset by cogeneration, atechnology that is not strictly a demand tech-nology but which could nevertheless reduceelectricity needed from the grid. I n the trans-portation sector, battery research as a key toelectric vehicles must compete with the effi-ciency improvements possible with high-mileage advanced vehicles using synthetic orbiomass-derived liquid fuels. The buildingssector is already the most heavily electrifiedand some electric technologies, such as com-mon appliances, are nearing saturation.

The achievement of highly efficient, electricdemand technologies would change not onlythe balance of fuels now used but also the sec-toral usage patterns of electricity, withdramatic growth in the industrial and transpor-tation sectors, and less in the buildings sectorwhich has shown the greatest postwar growthin electric demand.

Conclusion

It is likely that as technologies using elec-tricity are improved or new efficient uses arefound, improvements will be made in usingother future nonelectric energy sources suchas biomass and direct solar. While all of thesedevelopments are many years away, it is thisenvironment in which the SPS will compete.The success or failure of these new electrictechnologies will have a great deal to do withdetermining whether or not a market exists forSPS as well as the other large-scale, electric-generating technologies.

Energy Supply Comparisons

Introduction

Comparisons with other energy technol-ogies, both current and future, are a criticalpart of assessing a proposed new energy tech-nology. A host of criteria, only some of whichare readily quantifiable, is available for com-parison purposes. Costs, environmental im-pacts, scale, complexity, versatility, safety,and health risks are some of the more impor-tant factors of choice that ultimately deter-mine the relative desirability of a given energytechnology. For technologies currently inplace these factors are generally well known.For future technologies they are more oftenonly poorly known. Nevertheless, choicesamong future energy technologies must bemade, either in the R&D phase, or, later, in themarketplace.

Criteria for Choice

Whenever decisions to proceed with or haltthe development of a given technology aremade, it is important to lay out the frameworkof choice, to develop a set of criteria by whichone may judge the relative benefits and draw-backs of different technologies. In addition toproviding a basis for choice, such a list canalso help to identify the essential distinctionsbetween technologies and highlight areas thatwill need further R&D.

Table 14 lists 32 criteria developed in anOTA workshop that are often used in compar-


Table 14.—Criteria for Choice

Plant description1. Scale of power output (range in megawatts)2. Power output in relation to load profile (baseload,

intermediate, peaking)3. Versatility (other output besides electricity)4. Complexity (high, medium, low) and maintenance

requirements (controllability)5. Reliability (percent of time available to the grid)6. Nominal capacity factor (percent time operating)7. Material requirements8. Labor requirements9. Land requirements

10. Construction Ieadtime (years)11. Lifetime (what are key determinants)

costs12. Opportunity costs of RD&D (dollars and people)13. Net energy ratio14. Operating costs (cents/kWh)15. Capital costs ($/kW)16. T&D costs (cents/kWh)17. “Decommissioning” costs

Impacts18. Institutional (organization and ownership) impacts19. Safety and health risks (magnitude and distribution)20. Environmental risks (magnitude and distribution)21. National security risks of normal or unintended use22. Military vulnerability

Deployment consideration23. Time period to commercialization24. Geographic location; location of plant with respect to

load centers25. Compatibility with other technologies and utility grid

Other26. Probability for success (high, low, medium)27. Initial demonstration requirements (large or small)28. Resource constraints (domestic, international)29. Risks/impacts of RD&D failure (chance it may become

prematurely obsolete)30. Relative uncertainties to be resolved by RD&D (e.g.,

sensitivity of efficiency to design parameters)31. Is it a viable example for rest of world?32. Nature of R&D process (public, private, classified)

SOURCE: Office of Technology Assessment

ing electrical generating technologies. Most fitinto four broad categories: plant description,costs, impacts, and deployment considera-tions. These criteria establish a context forevaluating the SPS in relation to other futureenergy technologies.

Five Future Energy Technologies

In the timeframe that the SPS would be mostlikely to play a role in the U.S. energy future,the other energy sources that are likely tocontribute wilI be predominantly the renew-able and inexhaustible ones. OTA has chosento study the SPS in comparison to terrestrial

solar thermal technologies, terrestrial solarphotovoltaics, advanced fission (the breeder),and fusion. If the health and safety problemsof coal are satisfactorily solved, it could alsobe a major electric supply technology in theperiod that SPS could become available. In ad-dition, there may also be a component of con-ventional nuclear power still operating in thesecond and third decades of the 21st century(the timeframe after 2010 that is most likely forSPS deployment).

The data that OTA generated for these tech-nologies are supplemented by the electricalsupply comparisons which Argonne NationalLaboratory made for the Department ofEnergy (DOE/SPS) assessment program.3 DOEchose to study conventional and advancedcoal technologies, light water reactors, liquidmetal fast breeder reactor (LMFBR) breedersfusion, the reference system SPS, and ter-restrial photovoltaics operating in a peakingmode. Their data will be discussed along withthe results that OTA obtained. Coal and con-ventional nuclear power will be presented firstto provide a reference for the future energytechnologies in the discussions that follow.

THE COAL BENCHMARKThe coal resources of this country are

almost incomprehensibly large. Even if pro-duction were to triple, in that case coal wouldserve about half the present U.S. energy needs,known recoverable reserves would not be ex-hausted until late in the next century. Es-timated additional reserves could take thisproduction well into the 22d century. Thus, forall practical purposes, the supply of coal is in-exhaustible.

Unlike any other long-term energy source,coal can be exploited with known, proventechnology at costs that are competitive now.Advanced coal technologies such as com-bined-cycle gasifiers and magnetohydrody-namics, are not vital to coal’s future but could

‘M E Samsa, “SPS and Alternative Technologies Cost andPerformance Evaluations, ” The F ina l Proceedings o f the Solar

Power Sate//;te Program I?ev;ew, CON F-800491 (DOE), 1980.‘P rogram A$$e$sment Report Sta temen t o f F;nd/ngs, SPS Con-

cept and E valuation Program, DO F/E R-0085, 1980

83-316 0 - 81 - 8


improve the efficiency and economics of coal-fired electric power. Thus, of all the optionsfor large-scale, long-term production of elec-tricity, coal is the least uncertain technolog-ically and economically and it is appropriateto view it as a benchmark for evaluating theothers, including SPS.

Technological and economic criteria are notthe only alternatives to consider. Any energysource must have generally acceptable healthand environmental impacts. Coal evokes de-pressing memories of scarred landscapes, suf-fering miners and smokey skies. Today, thisreputation is no longer deserved. Modern coalmining and combustion techniques, whenproperly applied, have reduced virtually allthese objectionable impacts to the point wheredamage is clearly a small fraction of what itonce was.

The actual future of coal, however, is muchless certain than its potential. Issues arisingwhen expanded mining and use are consideredcan be divided into three categories: interrup-tions, control costs, and risks. These will bediscussed in some detail because if coal doesnot realize its potential, the reasons will prob-ably be found here.

Interruptions are intermittent events thatprevent scheduled plans from being fulfilled.Strikes by miners and transportation break-downs are obvious examples. Opposition by in-tervenors that prevent facilities from beingbuilt might be included here. These factorscan’t be completely eliminated, but properplanning can reduce disruption. The majorlong-term effect is to deter potential usersfrom turning to coal if they have other optionsand are concerned about the reliability of thecoal supply.

The cost of controlling coal’s negative im-pacts is high. Reclaiming surface mined landsand reducing the emissions of combustionhave received the most attention. For instance,the Clean Air Act Amendments of 1977 haverequired the use of the “best available controltechnology” for limiting emissions of sulfuroxides. Utilities have been concerned not onlybecause of the expense of the flue-gas scrub-

bers, but also because the equipment in usehas generally shown disappointing reliability.However, current systems appear to be consid-erably better than early designs, so utilitiescan, if they are careful, be confident that theirequipment will function reliably and effec-tively.

The regulatory approach has been to ensurethat the impacts are controlled to the pointwhere it is clear that known damages aresharply reduced. As mentioned above, it ap-pears that this goal has been achieved. Asmore information is gained, it is possible thatcontrol can be loosened without increasing therisk. For instance, new data on the damagecaused by sulfur oxides and sulfates, and bet-ter data on the long range transport and chem-ical transformation of these and other pollut-ants might allow more selectivity in emissionscontrol. Thus, the costs of controlling impactsmay be reduced rather than increased in thefuture. Such a reduction would improve coal’scompetitiveness with nuclear power or SPS,unless some of the unproven risks are con-firmed.

There are three major risks to long-term coalcombustion that could limit expansion ormake it much more expensive: public healtheffects, acid rain, and carbon dioxide (C02).Coal combustion pollutants have been linkedby statistical analyses to tens of thousands ofdeaths per year. These studies are highly con-troversial and have been neither proven nordisproven. If they are generally accepted, con-siderable reduction of sulfur and nitrogenoxides would probably be necessary. Thisreduction would probably call for greater useof coal cleaning before combustion, combus-tion modifications and higher efficiency flue-gas desulfurization systems. Such changeswould be expensive but unavoidable if thepublic demands cleaner air because of con-cerns over health risks.

The documentation for damage by acid rainis better than for public health effects, but isstill not conclusive. Acid rain is evidentlycaused by the same pollutants suspected in thepublic health issue, but the scientific under-


standing of pollutant transport and chemicalconversion is poor. Furthermore, while acidifi-cation of certain lakes and streams is stronglysuspected, extensive damage to terrestrial eco-systems is only surmised. If this damage isproved and found too costly, the remedywould be the same as for public health effects.However, it must be emphasized that proof ofdamage is insufficient. The pollutants must betraced back to their source in order to knowwhere to implement controls. Otherwise inef-fectual or overly expensive control strategiesmay be implemented.

The final risk, excessive CO2 released to theatmosphere, is by far the most intractable. Theadverse impacts that have been suggesteddwarf those of any other human activities withthe possible exception of nuclear war, The C02

produced by burning fossil fuels and clearingforests accumulates in the atmosphere. Someof the CO2 that is produced is absorbed in theoceans, but the dynamics of the CO2 balanceare not well-understood. The concentration inthe atmosphere is increasing by 5 percent peryear since 1958. C02 is transparent to most ofthe incoming sunlight that warms the Earth.Normally much of this is radiated back tospace in the form of infrared radiation, butCO, tends to absorb and block this longerwavelength radiation. This mechanism, thegreenhouse effect, is an essential ingredient inmaintaining the proper temperature balanceon the Earth. However, if sufficient quantitiesof CO2 are added to the atmosphere, addi-tional heat will be trapped to warm the Earthsignificantly.

A number of studies of atmospheric CO2

levels predict that concentration will rise totwo to eight times today’s level in the 21st and22d centuries. While there is continuing discus-sion about the effects of this buildup, the ma-jority of the scientific community agrees thatthe probability of global warming and otherclimate changes is sufficiently high to warrantexceptional attention.4 Changing climate pat-terns, even if they turned out to be ultimatelybeneficial, would cause enormous disruption,especially with agriculture. At least 10 years

40ffice of Technology Assessment, U S Congress, The Direct

Use of Coal, OTA-E-86, 1979

will be required before enough is known tomake intelligent decisions about the signifi-cance of the effects of increased CO2 in theatmosphere. The contribution of fossil fuelcombustion to the CO2 buildup, the results ofthis buildup on the heat balance and climate,and the effects of climate changes must all bestudied extensively. At some point, however, itmay be necessary to limit coal combustion inorder to limit CO2 emissions since it is highlyunlikely that any practical means of removingCO2 from the flue gases will be devised.

In summary, as far as we can tell now, coal iscapable of supplying most of the electricpower this country is likely to need for manygenerations. The effects of the release of extraCO, to the atmosphere are sufficiently indoubt that other options must be prepared incase they are required. However, until weknow that it constitutes a serious problem thedevelopment of other options must be justifiedon the basis that they will be cheaper or moreattractive in some other way than properlycontrol led coal.

CONVENTIONAL NUCLEAR

Conventional nuclear plants totaling 55,000MW of power are now operational and another106 reactors totaling 118,000 MW are either onorder or under construction.5 This is a substan-tial base for the nuclear technology, but it isquestionable whether it will be fully realizedor expanded because of public opposition,licensing problems, financial uncertainties,and eventualIy resource Iimitations.

Public opposition has been especially visi-ble. While public opinion polls still show sup-port for nuclear energy, this support has beenweakened for several reasons. Low-level radia-tion release and other problems with routineoperations contribute to public concern. Pub-lic support has also eroded because of con-tinued lack of a suitable site and demonstratedmeans for nuclear waste disposal. Further mis-haps such as the accident at Three Mile Islandcould condemn the technology in the eyes ofmany who now reluctantly accept it. Finally,

‘Department of Energy, “U S Central Stations Nuclear Gener-ating Units, r’ September 1980


the possibility that nuclear energy could con-tribute to nuclear weapons proliferation dis-turbs many, though it is debatable whetherrenunciation of the nuclear option by theUnited States would materially reduce thisrisk.

Most of these problems, except prolifera-tion, can be ameliorated by improved technol-ogy, procedures, and regulations. But if im-provements are not made quickly, publicopinion could swing against nuclear power inthe United States as it has on occasion in otherWestern democracies (e.g., Sweden and Aus-tria). Even if opponents remain in a minority,they can find many opportunities to troublethe industry through legal actions, regulatoryappeals and ballot initiative. None of thesemay kill a particular project, but they coulddiscourage utility executives from choosingthe uncertainty and frustration associated withnuclear power as long as they have other op-tions such as coal.

Utility decisionmakers also have to considerlicensing and financial uncertainties. At pres-ent, many design criteria for nuclear plants areso poorly defined that it is virtualIy impossibleto get a new reactor licensed. ’ This problemmay be resolved over the next few years, butrecent trends have not been reassuring. For in-stance, a review now underway—to determineif fundamental changes in reactor designs arenecessary to contain melted fuel cores in caseof severe accidents— is expected to last sev-eral years.

Some regulatory rulemaking problems stemfrom a lack of conclusive data. Others appearto reflect the Nuclear Regulatory Commis-sion’s lack of a clear picture of what it wantsto accomplish and how to do it. Both types ofuncertainties have to be resolved before theutilities wiII consider ordering many more reac-tors.

Utility companies also face uncertainty con-cerning both the capital available to buildplants and the risk of a long-term shutdown.The cost of a new nuclear plant is now close to

‘Office of Technology Assessment, U S Congress, Nuclear

Powerp/ant Standardlzat/on, OTA-E-1 34, April 1981

$2 billion. Not many utilities can raise thatmuch capital, even when the projected costsof power at the busbar are favorable. Evennow, many plants are being built as joint ven-tures by several companies. A continuation ofhigh interest rates could delay many plans forcapital-intensive projects. And after an expen-sive reactor starts operation, the utility bearsan additional economic risk due to the possi-bility of unplanned shutdowns. The Three MileIsland (TMI) accident and the Browns Ferry f ireled to lengthy shutdowns that forced huge ex-penditures by the owner utilities, which thenhad to generate or buy expensive replacementpower. The present financial difficulties of theowner of Three Mile island, General PublicUtilities, illustrate how critical this concernwill be for other utilities.

Availability of fuel will eventually be aserious constraint if conventional reactors areused in the midterm to long-term future, with-out a shift to advanced nuclear breeders. TheCommittee on Nuclear and Alternative EnergySystems (CONAES) estimated that enough ura-nium exists in this country to fuel at least400,000 MW for the lifetime of the reactors (40years). ’ This would allow the construction ofanother 227,000 MW of capacity. If ordering ofnew reactors resumes in 1985 and continues atthe rate of 10 reactors per year, the last onewouId be ordered in 2008. Because of retire-ments, by 2050 nuclear power would be backto near its present level. Peak energy outputunder this scenario would be about 5.6 (enduse) Quads in 2015. However, discovery ratesfor uranium ore and imports and exports ofuranium could change the total availability inan unpredictable way.

The greatest single long-term uncertaintyfacing the industry is the future electricitygrowth rate, just as it is for the SPS. Over thenext several decades, moderately high growthrates might require much more nuclear power,but as discussed in this chapter, the growthrate may be more modest. However, lowgrowth need not preclude nuclear, and might

‘f nergy In Transition, Committee on Nuclear and AlternativeEnergy Systems (CONAES), National Academy of Sciences,VVashlngton, D C , 1979

Ch. 6—SPS in Context Ž 109

enhance the attractiveness of nuclear com-pared to other future central power options,such as SPS, that require large deployments tojustify the development cost.

Nuclear energy can have a future if its prob-lems are addressed effectively and decisively.To some extent this is happening. The accidentat TM I has revealed weaknesses in reactorplant design and operator training, to whichthe industry and the NRC are responding withinitiatives such as the Institute for NuclearPower Operations and the Nuclear SafetyAnalysis Center. As a result of the events in thepast 2 years, both regulators and utilities seemmore conscious that extreme safety is in every-one’s interest.

Whether these measures will ensure safetyin the future and enhance the industry’s publicimage without pricing the technology out ofreach is still an open question.

FIVE FUTURE TECHNOLOGIESThe following discussion summarizes the

salient characteristics of the four centralrenewable or inexhaustible energy technol-ogies that have been chosen for comparisonwith the SPS. While each of these alternativesis compatible with centralized electricity pro-duction in a utility application, they are notequally applicable for baseload power produc-tion. Photovoltaics and solar thermal sourcesvary over the course of a day and the season ina fashion that makes them well-suited forpeaking applications. Fusion, the breeder andSPS would work most efficiently producingconstant power 24 hours per day, so they arenaturally suited for baseload power produc-tion. The applicability of photovoltaics andsolar thermal can be broadened to cover in-termediate and possibly baseload applicationsby the addition of storage capability, but overthe next 10 to 20 years there may be littlecause to do so, for two reasons. The first is thatthe most cost-effective application of solarthermal and photovoltaic systems is likely tobe as fuel savers until all the oil and gas-firedgenerating facilities have been retired fromutility systems. Second, electric storage is farmore versatile and cost effective for a utility if

it is not restricted for use with a single plant. Arecent study by the National Academy ofSciences’ concludes that when wind, photovol-taics, or solar thermal is used in a utilitysystem, “it is typically not desirable to havededicated storage but wiser to provide thebackup energy from the grid.” Except for asmall amount of storage to handle short-termvariations of sunlight in solar thermal applica-tions, the conclusion that dedicated storage isnot appropriate for terrestrial renewable elec-tric technologies is generally well-accepted.

Currently, electrical generation is fueledlargely by oil, natural gas, coal, fissionablematerial, and stored water. For the time periodwhen the SPS is most likely to find applicabili-ty, there may not be as great a diversity ofenergy supply technologies connected with theutility grid as is now enjoyed; hence terrestrialsolar technologies may be used in a differentmode than the one that seems most desirablenow (i. e., peaking or intermediate). It is alsodesirable to compare all the future electrictechnologies on a common basis. For thisreason, OTA has prepared cost estimates forsolar thermal and photovoltaics operating in abaseload mode. Because photovoltaics alsopossess the unique property among thesefuture energy systems of being modular on avery small scale, its use in a dispersed mode—both connected to the electric grid and inde-pendent of it– will be discussed in a separatesection. In the future, it would be also worth-while to compare SPS to an energy scenariocomposed of a number of dispersed solar tech-nologies working in complementary fashion.

The following discussion will give the majorcharacteristics, cost sensitivities and uncer-tainties, factors affecting deployment, andforeseeable impacts of the different renewableand inexhaustible energy sources. First, a shortsummary of each technology will be given, fol-lowed by comparisons. Table 15 presents therelevant characteristics of each of the 5 tech-nologies in matrix form.

*“Energy Storage for Solar Applications,” Committee on Ad-vanced Energy Storage Systems, National Academy of Sciences,1981


Table 15.—Characteristics of Five Electrical Technologies

Criteria Fusion Breeder SPS Solar thermal PhotovoltaicsPlant descriptionScale of poweroutput

Power output inrelation to loadprofile

Versatility

1-100 GW (lasers 10 kW to greater 10 kW-100 MWsmaller) than 100 MW

Base load Peaking, intermediate, Peaking, intermediate,baseload (with stor- baseload (with storageage, but expensive at expensive)high-capacity factor)

Centralized, limited ver- Also cogeneration, Cogeneration?

500-1,500 MW

Baseload

500-1,500 MW

Baseload

Also large-scale, low-temperature processheat; synfuels; pro-duction of fissilematerials

MediumSame as LWR (fuelcycle reliability?)

Same as LWR

None

Like LWR

Same as LWR

Also large-scale, high-temperature processheat; synfuels, pro-duction of fissilematerials

HighBetween 0.6 and 0.75

satility. Some militaryconnection andrelevance to spacecolonies and spacemanufacturing

HighNo good reason tothink it’s worse thansteam technologies.Between 0.6 and 0.9(laser-exception)

Between 0.6 and 0.9

high-temperature proc- -

ess heat

ComplexityReliability

Low LowestBetween 0.6 and 0.9, Greater than 0.9 ( = 1-Iike other steam time for repair)plants

Nominal capacity 0.6 to 0.75 Without storage: 0.2 to Without storage: 0.2 to0 .25 . Wi th s to rage : U P 0.25 . Wi th s to rage : U Pfactorto 0.9 to 0.9. Also depends

on regionPlentiful, domesticmaterials, like nuclear

Materialrequirements

Design specific, candesign around; stayaway from specializedalloys

Like LWR

Can design around,common material, so-phisticated process-ing

Few and skilled forspace construction,less skilled for receiv-er construction

Comparable to other

Plentiful, domesticmaterials; need tobuild manufacturingindustry

Moderate to large, de-centralized larger

Laborrequirements

Moderate to large,decentralized larger

Landrequirements

Same as LWR. Lessthan 1 acre/MW (in-cluding fuel cycle)

5 to 12 years?

5 to 10 acre/MW 10 acre/MW incre-mental addition couldbe zero

Short; minimum 48hours for 7 kW

Greater than 30 years

centralized solarsystems; 6.5acres/MW or less

5 to 12 years (including Similar to other cen-ConstructionIeadtime

Lifetime

5 years for 1OO-MWplantlicensing) tralized technologies,

5 to 12 yearsGreater than 30 years;design like othersystems, but limitedexperience

$40 billion to $100billion to achieve firstoperating satellite

2- to 20-year payback

Greater than 30 years(first wall material)

Greater than 30 years(replace steamgenerator;

$10 billion to $15billion (?)

l-year payback

1 to 2¢/kWh

$1,500 to $2,000/kW

Greater than 30 years

Costs of RD&D $20 Billion to $30

Unknown

Almost no fuel costs.Same as LWR, butless confidence

$2,000 to $2,500/kW;

Low $0.5 billion plus$0.5 billion to $1.0billion


$1 billion to $2 billion

Net energybalance

Operating costs


0.3 to 1.5¢/kWh; low aspercentage ofdelivered cost

$1,500 to $17,000/kW

1 to 4 percent of capital 1 percent; $20/kW/yr;costs; $40 to less for centralized$60/kW/yr

$1,500 to $3,000/kW $2,000 to $3,000/kW(peak) ($1.60 to$2.20/PW) (withoutstorage)

Centralized—same as Centralized—same asother systems; decen- other systems; decen-tralized is negligible tralized is negligible

Capital costslower for a 5-GW plant

T&D costs Same as any centralsystem

Minor

Similar to presentinstitutional structure

Same as any centralsystem

Minor

Similar to presentinstitutional structure

Similar or greater thanother central systems(reliability). Need toconsider outage prob-lem

Push out of orbit. Smallat 4-percent discountrate over 30 years

Decommission-ing costs

Negligible Negligible

ImpactsInstitutional im-pacts (owner-ship)

Requires new manage-ment organization; in-ternational involve-ment possible

Decentralized— medi- Decentralized— medi-um to high impacts; urn to high impacts;centralized— similar centralized— similarto present infra- to present infra-structure structure


Table 15.—Characteristics of Five Electrical Technologies (continued)

Criteria Fusion Breeder SPS Solar thermal Photovoltaics

Safety and health Safer than PWR Fuel cycle? Same as Microwave bioeffects Smallrisks PWR (higher power uncertain; ionizing Low; possible safety

density, lower radiation in GEO hazard with decentral-pressure) ization in event of fire

Environmental Small for routine opera- Small for routine opera- Upper atmosphere ef- Smallrisks tion tion fects uncertain

Low possible manu-facturing risk of PV

National security Designs other than Significant weapons Not efficient weapon None, possible benefits None, possible benefitsimplications hybrid less significant Proliferation potential but transportation ca- of exporting benign of exporting benign

than breeder -

Military Same as any centralvuInerability ized powerplant

Deployment considerationsTime to commer- 30 years plus

cialization

Geographic Ioca- Low population areation with re-spect to loadcenters

Compatibility Goodwith other tech-nologies andutility grid

OtherProbability for Low to mediumcommercialsuccess

Demonstration Large, but not as largerequirements as SPS

Resource Noneconstraints

Risks of RD&D High, but for next 10failure years little risk, $20

billion

Relative High, complexuncertainties

Is it a viable ex- Yesample for therest of theworld?

Nature of RD&D Magnetic—public;process inertial —classified

pabilities significant technology are good technology are goodSame as LWR Slightly greater than Low Low

other central power-plants, depends onspace capability ofother nations

(Developed) 15 to 20 Long (greater than 20 Between 5 and 10 years Decentralized—5 years;years domestic (Iicen- years) centralized— 10 yearssing)

Low population area Low population, no Decentralized—very Decentralized—verywater needed; mixed close; centralized— close; centralized—

S. W.-less than or S. W.-less than orequal to other sys- equal to other sys-tems. Geographic de- tems. Geographic de-pendence high pendence high

Penetration may be Iim- Goes down with higher Goes down with higherGoodited to 20 percent.Competes with othertechnology. Nothingobviously unsolvable

High Low to medium

Moderate cost for 500 Large cost (0.3 to 1to 1,000 MW. About $1 GW)billion

None Manageable

Technology is here, but High—big program;public views regarding depends on programwaste? size (wait until HLLV

available)Small High

Proliferation? for de- Yes, if t worksveloped countriesonly?

Much public money Public funds forspent, remainder RDD&T. Then privatemight be private, but capitalfor regulatory uncer-tainties

percentage penetra-tion; negligible prob-lems

High

Small (1OO-MWaggregate of 2 to 3demos)

Small

Negligible

Small (O&M costs)

Easier to digest insmall to moderatechunks

Needs to be demon-

percentage penetra-tion; negligible

High

Small (community sys-tems are medium)

Small

Negligible

Cell costs

Easier to digest insmall chunks; needmanufacturer capac-ity, but good example

Need not be demon-strated by Government strated by Govern-with private partici- ment, large privatepation; industry will contributiondevelop



1. Central Solar Thermal.– Solar thermaltechnology is the oldest of the technologiesunder study. It may also be the one that isnearest to commercial application, since apilot plant is already under construction in thiscountry. The concept involves simply collect-ing concentrated solar radiation to heat aworking fluid in a central receiver (boiler),which in turn drives a turbine to generate elec-tricity. It has the versatility to provide eitherelectricity or process heat (steam) for in-dustrial applications.

Two generic systems have been proposed forthe solar thermal approach: line-focus andpoint-focus systems. In the line-focus scheme,the Sun’s radiant heat is reflected and focusedby parabolic trough mirrors onto tubes con-taining the working fluid. The working fluid ispumped to a central site where it may be usedto drive an irrigation pump, produce hot wateror steam for a factory, or produce a combina-tion of heat and electricity for a small com-munity. The line-focus approach is alsofavored for process heat applications such asenhanced oil recovery, but is not being ac-tively considered by DOE for central electricapplications.

In the point-focus or “power tower” system,a field of reflectors (called “heliostats”) isfocused on a central receiver atop a tower inthe center of the field. Although there areseveral designs, a heliostat is basically a flatreflective surface mounted on a computer-monitored gimbal that allows it to automati-calIy track the Sun’s course across the sky. Theheliostat/power tower approach is being pur-sued by DOE as a central generating system,though not exclusively so. * It can be used forelectrical generation either in a stand-alonesystem or as a method for repowering existingfossil-fueled power stations. The place of solarthermal in a utility system —whether it servesas a peaking, intermediate, or baseload unit—depends on the storage capability of the solarthermal plant. Without any auxiliary storage,

*In 1980, DOE initiated six major studies of the applications ofthe power tower to a variety of industrial heat demands, rangingfrom low-quality steam for uranium leaching to high-tem-perature steam for reforming methane to ammonia,

its effective capacity factor will be about 23percent in a location such as the southwesternUnited States. Addition of a modest amount ofstorage (sufficient for 3 hours of extendedoperation per day) will increase the capacityfactor to about 40 percent and make it possi-ble for the plant to supply part of the late-afternoon electric consumption peak that oc-curs in many utilities. Because it is desirable tosmooth out the effects of short periods ofcloud cover, it is likely that the technology willincorporate at least a small amount of thermalstorage (up to 1 hour). Solar thermal plantscould be made to operate in a baseload modewith the addition of a large amount of storage,but this increases the system’s conversion losesand raises the overall cost per kilowatt in-stalled. Solar thermal will, therefore, probablybe better suited for intermediate or peakinguses since its daytime availability correspondsclosely with the peak of the electricity loadprofile in many areas.

Solar thermal plants will be intermediate inscale between today’s coal or nuclear plantsand small onsite generators. They can be ex-pected to be deployed relatively quickly– per-haps within 5 years for a 100-MW plant.

The technical feasibility of solar thermaltechnology is established. Engineering ques-tions remain about the materials to be used inthe design of the central receiver. What is atstake in making the technology commerciallyviable is whether plants can be produced eco-nomically. The single most important factor isthe cost of heliostats, which accounts forabout one-half the cost of solar thermal de-signs. Present cost estimates range from $1,000to $3,000/kW of capacity installed.

Much of this high cost reflects the cost ofmaterials. Savings realized from future auto-mated production techniques are built intothese projections. Thus, the economic viabilityof solar thermal technology depends on attain-ing heliostat cost goals.

The research, development, and demonstra-tion (RD&D) costs associated with the solarthermal development are expected to be in therange of $0.5 billion to $1 billion. In addition


to continuing tests and studies to reduce helio-stat costs, R&D for efficient and cost effectivestorage methods, improved receiver designsand transport fIuids are also needed.

2. Solar Photovoltaics. This technology is thenewest of the terrestrial solar options understudy and it is conceptually the simplest, sinceit converts sunlight directly to electricitywithout any working flu ids, boilers or genera-tors. Because the essential element—a semi-conductor wafer or “cell” — is modular at avery small size, the technology has a versatilityin scale of deployment that surpasses anyother option. Photovoltaic (PV) cells havealready proved feasible in small-scale applica-tions for both space and terrestrial purposes.However, central PV systems have not beentested yet, even in a pilot plant size. Becausethe technology is so intrinsically modular, theR&D program is not geared to the demonstra-tion of a series of prototype plants but to theimprovement of the cost and performancecharacteristics of the celIs.

A variety of different semiconductor materi-als is being developed for possible use in cen-tral PV systems. When sunlight falls on wafersof these materials, it produces a direct currentof electricity. The efficiency of this processdepends on many semiconductor properties,and how well those properties match the wave-length spectrum of sunlight. Typically, thematerials produce a direct current (DC) voltagelevel of about 0.5 volts. Some of the morepromising PV developments include the fourtechnologies discussed below.

• The single cell silicon technology is themost highly developed, and its introduc-tion dates back 23 years to the beginningof the National Aeronautics and SpaceAdministration (NASA) space program. Itsproperties are well understood and cellssold commercially for small-scale applica-tions routinely achieve efficiencies of 10to 13 percent; experimental cells haveachieved 15 percent and the theoreticallyprobable maximum is 20 to 22 percent.The single most important barrier to com-mercial use is the high production cost,

●

●

●

even though costs have dropped and per-formance improved over the past decadein line with DOE projections. Further costreductions to ($95/m2) $0.70/peak watt)and performance improvement to 13.5-percent efficiency are the DOE goals for1986.The cadmium sulfide/copper sulfide tech-nology is another approach that is com-mercialIy available and holds promise forimprovement. This material can be usedin thin films because of its high ab-sorbance of sunlight, with a reduction infabrication costs and materials require-ments. Experimental cells have achievedefficiencies of 9 percent, with limitedlifetime. Improved cells have the poten-tial for cost reductions to $10/m2 at 10-percent efficiency. A number of othercadmium sulfide technologies are understudy for thin film and standard cells.The gallium arsenide technology isanother alternative that has achieved effi-ciencies up to 24.5 percent in experimen-tal cells. The material can be fabricated inthin films (with experimental efficienciesto 15 percent) and can withstand concen-trated sunlight at high temperatures. Itsmajor disadvantage is that commercialproduction is still some time away andcosts remain much higher than for single-crystal silicon.The polycrstal l ine and amorphous si l icontechnologies have the potential for ordersof magnitude cost reductions comparedto the single-crystal silicon technology,but the experimental cell efficiencieshave so far only reached 9 to 10 percent.(The probable maximum is estimated tobe at least 15 percent for the amorphoustechnology in thin film cells.) These tech-nologies are not limited to silicon, but arecurrently being investigated along withother novel materials concepts.

All the technologies discussed above arecandidates for use in flat-plate arrays of cellsthat absorb unconcentrated sunlight. Galliumarsenide is also an example of a high-effi-ciency material that can be used with a con-


centrating system. Concentrating systems in-volve different tradeoffs and are further fromcommercial viability than flat-plate systems.Both line- and point-focus collectors are underconsideration for PV concentrating systems.Costs of concentrating systems can in principlebe low, since the receiving area needs only tobe covered with a thin reflective sheet, but thetechnology is not developed enough to makeproject ions yet.

Up to half the cost in a flat-plate design ter-restrial solar photovoltaic plant today is forthe cells themselves. Other requirements for acomplete plant are materials for packagingand supporting arrays of celIs, support struc-tures, cabling to connect the arrays andmodules, and power conditioning equipmentto convert the DC voltage to alternative cur-rent compatible with the utility grid. About 300cells would be combined into one panel, 30panels into one array, and 10,000 arrays intoone module supplying 25 MW of peak power.

A central plant might produce 200 MW from 8modules. Storage could be added to extend thecapacity factor of the plant, at additionalsystem cost. As discussed in the introductionto this section, the economic merit ofdedicated storage for utility-based PV systemshas been seriously questioned.

The pace of technological breakthroughs inPV technology is impressive. Today single-crystal silicon cell arrays cost 15 percent ofwhat they did in 1974, as can be seen in figure27. It is on further orders-of-magnitude costreductions that both terrestrial and SPS PVsystems depend. Such price reductions arecommon in the semiconductor industry forproducts with large markets (e.g., digitalwatches, hand calculators, and now hand com-puters), but they are nearly unheard-of in theenergy industry. Therefore, planners familiarwith conventional thermal and nuclear energytechnology sometimes find them difficult toaccept. The goals for the DOE PV program are

Figure 27.— Recent and Projected Solar Photovoltaic Prices

30

5

n


for array prices of $2.80/peak watt in 1982,$0.70 in 1986, and $0.15 to $0.40 in 1990 (all in1980 dollars). At the 1990 level, complete sys-tems are expected to cost $1.10 to $1 .80/peakwatt.

Although significant breakthroughs have oc-curred in the past 5 years, the principal thrustof PV research is still directed toward the iden-tification, selection, and engineering refine-ment of the cheapest possible semiconductormaterials. A concomitant part of this effort isthe development of suitable mass-productiontechniques (now being most intensively pur-sued for single-crystal silicon and cadmiumsulfide) to open the way for mass marketpenetration. It is upon the outcome of thistwo-pronged effort (development of cells anddevelopment of better manufacturing tech-niques) that the success of central terrestrialPV plants will depend.

The time-scale for commercial readiness ofcentral terrestrial PV plants could be as shortas 5 years or as long as 15 years. The balance ofa central PV plant uses familiar buildingmaterials and readily available power-handlingequipment. Once arrays are available, plantconstruction Ieadtime should be short. Ac-cording to the DOE program, commercialreadiness could occur in the early 1990’s. If theRD&D program for PV cells is accelerated thisdate could be earlier; on the other hand, slip-page in the schedule for cell developmentcould delay commercial introduction.

Subsequent deployment of central PV sys-tems would be paced by the rate of growth ofnational manufacturing capacity for PV cells.To achieve substantial penetration of centralPV in the time period of 1990 to 2010 will re-quire an aggressive program for PV man-ufacturing plants. It is possible that decen-tralized PV centralized terrestrial and SPSenergy systems could all be competing for theoutput of the PV industry during this period.

3. Advanced Fission (Breeder Reactor).– Con-ventional reactors use uranium ore very ineffi-ciently because only a small fraction of theuranium is tapped for energy. Natural uraniumconsists of two isotopes 99.3 percent U-238

and 0.7 percent U-235. Only the U-235 is usabledirectly in a conventional reactor. With con-ventional reactors, uranium resources wouldbe exhausted relatively rapidly by an expand-ing nuclear energy base. Breeder reactors onthe other hand, can extract 100 times as muchenergy from a ton of uranium ore and thus ex-tend the nuclear energy resource by severalcenturies.

In a breeder, the core of the reactor is sur-rounded by a blanket of the type of uraniumnot burnable in conventional nuclear plants.This uranium captures neutrons escaping fromthe chain reaction in the core and is trans-muted into plutonium, a premium v a l u enuclear fuel. In this fashion, a breeder“breeds” new fuel that is extracted from theblanket, converted into fuel rods, and laterburned in the same or another reactor. An ad-vanced breeder will produce about 10 percentmore fuel than it burns. A different fuel cyclecould use thorium in the blanket. Thorium isan element similar to uranium, but it cannot beused directly as a fuel. In the blanket, ittransmutes to U-233 which is a good fuel.

Breeders may also be distinguished by thedifferent types of coolants used to carry heatfrom the core to the generating side of anuclear plant. Because the interconnectionsbetween the core and the generators are quitecomplex, requiring considerable engineeringrefinement, the choice of coolant defines con-ceptually different types of breeders as muchas or more than the choice of fuel. Early inits program, the United States emphasizedbreeders with liquid metal (usually moltensodium) coolants and the reactor concept thatevolved —the liquid metal fast breeder orLMFBR– has become the reference system forbreeder research in other countries, represent-ing more than 95 percent of the dolIar effortdevoted worldwide to breeders. Thirteen reac-tors using the LMFBR concept have been built,the most successful being the French Phenixreactor, and seven countries with majorbreeder programs (table 16) have all empha-sized the LMFBR type. Alternatives are heliumgas, molten salt coolants, and water.


Table 16.—Description of Milestones of Major Breeder Programs

Federal RepublicFrance of Germany Japan

ReactorsRapsodie (24 MWt)Phenix (250 MWe)Super Phenix (1,200 MWe)

KNK-I (58 MWt)KNK-11 (58 MWt)SNR-300 (300 MWe)SNR-2 (nominally 1,600 MWe)

1. 1960—GFK, Karlsruhe projectbegins

2. 1964—Design study for 1,000 MWeLMFBR

3. 1966—SNEAK startup4. 1975—SNEAK experiments for SNR

3005. 1967—INTERATOM F.R.G. and

BENELUX cooperationbegins

6. 1972—KNK-I goes critical7.8.9.

10.11.

12.13.

14.

15.16.17.18.

1976—KNK-11 goes critical1969—SNR-300 safety report1970—SNR-300 company estab-

lished1971—SNR-300 revised safety report1972—SNR-300 sodium fuel pumps

tested1973—SNR-300 construction begins1974—SNR-300 steam generators

and IHX test1975—SNR-300 specification of fuel

and cladding1980—SNR-300 goes criticala

1974—SNR-2 company established1976—SNR-2 preliminary designa

1981 —SNR-2 construction beginsa

Joyo (100 MWt)Monju (300 MWe)

1. 1967-Joyo conceptual design2. 1969—Joyo safety evaluation3. 1970—Joyo construction begins4. 1977—Joyo goes critical5. 1968—Monju preliminary design6. 1969—Monju conceptual design7. 1973—Monju safety evaluation8. 1978—Monju construction begins

-10. 1986—Demo plant begins-11.1991 —Demo plant goes critical-12. 1988—Commercial plant 1 con-

struction begins

critical-14.1991 —Commercial plant II con-

struction begins

critical

as~h~d”l~ as of 197& In 1980, the SNR program currently in flux. SNR-301) designed but not yet licensed. SNR-2 not Yet designed. Entire Pro9ram will sli P substantially,but the new schedule is not known at this time.

SOURCES: France: U.S. Energy Research and Development Administration, The LkfFBR Program In France, ERDA 76-14, March 1976; M. D. Chauvin, “The FrenchBreeder Reactor Program,” 1976.Federal Republic of Germarty: U.S. Energy Research and Development Administration, The /_ J14FBR Program in Germany, ERDA 76-15, June 1976.Jepem Report of Ad Hoc Study Committee organized by Japanese Government Science and Technology Agency, October 1977.

SOURCE: International Energy Associates Limited, 1980.

United Kingdom United States U.S.S.R.

ReactorsDFR (60 MWt) Clementine (25 kWt)PFR (250 MWe) EBR-1 (1.2 kWt)CFR (commercial size) Fermi (200 MWt)

EBR-11 (16.5 MWe)Clinch River (375 MWe)Fast Flux Test Facility

(equivalent of 160 MWe)PLBR (commercial size)CBR (commercial size)

1. 1953—first nuclear power programbegins

2. 1964—second nuclear power pro-gram begins

3. 1963—DFR goes critical4. 1984-PFR construction begins5. 1972—PFR goes critical

1. 1946—Clementine goes critical2. 1951—EBR-1 goes critical3. 1963—Fermi goes critical4. 1966—Fermi shuts down5. 1983 -EBR-II goes critical6. 1971–SEFOR (U.S. and F. R. G.)

goes critical

BR-5 (10 MWt)BOR-60 (60 MWt)BN-350 (1 ,000 MW)DN-600 (600 MWe)

1. 1958—BR-5 goes critical2. 1965—BR-5 operates full core3. 1969—BOR-60 goes critical4. 1973—BN-350 goes critical5. 1973—BN-600 construction begins6. 1979—BN-600 goes critical7. 1975—1,600 MWe reactor design

underway

Ch. 6—SPS in Context ● 1 1 7

Table 16.—Description of Milestones of Major Breeder Programs (continued)

United Kingdom United States - U.S.S.R.

aThi~ ~a~ the IJ,S, program in 1978, Currently there ,~ no planned pLBR schedule, penal Ing final ~eclsions on CRBR. CRBR iS “in Construction, ” but has been in a hold-ing pattern for 2 years.

SOURCES: United Kingdom: Prepared by IEAL from compilation of U.K. documents.United Statas: U.S. Energy Research and Development Administration, .LIquKI k4efa/ Fast Breeder Reactor Program, January 1977; U.S. Energy Research andDevelopment Administration, The LMFBR Program in France, ERDA 76-14, March 1976; Ford Foundation, Nuc/ear Power Issues and Choices: Report of theAJuc/ear Energy Po/icy Study Group, 1977. Note on U.S. program: Items 9-15 refer to the program as it stood in April 1977, The plan and schedule has been inrevision since then, but it is not yet available.U. S. S. R.: United States Nuclear Power Reactor Delegation, “Report of the ~Jnited States Nuclear Power Reactor Delegation Visit to the U. S. S. R,, June 1-13,1975,” 1975.

SOURCE: International Energy Associates Limited, 1980.

As a source of centrally generated electric-ity, the breeder has been proven feasible at thepilot plant scale and at an intermediatescale but awaits demonstration at commercialscale —that is the 1,000-MW size of new con-ventional reactors. Its operating character-istics are expected to be similar to a conven-tional (light water) reactor, except that it willhave higher thermal efficiency and thereforeless thermal pollution. Breeders may also inprinciple be used for industrial process heat.The Russian breeder BNR-600 produces elec-tricity and desalinated water.

The technology was demonstrated at a pilotplant scale in the United States in 1963, when a10-MW reactor named EBR-II started produc-ing electricity in Idaho. Between the 1960’sand 1970’s, technical leadership shifted fromthe United States to France. The Phenix whichhas produced electricity for more than 5 yearsat Marcoule, France, demonstrated successfulscaling from 10 to 250 MW, but suffered sometechnical problems that required the plant toshut down for more than a year. Its breedingrate is considered too slow for commercial use,and some components (especially steam gen-

erators) are not extrapolatable to commercialsize. France, together with the FederalRepublic of Germany and Italy, is now build-ing a 1,250-MW reactor incorporating an im-proved design – Superphenix – at Creys-Malville. Due to go critical in 1985, it will bethe first commercial prototype breeder.

The time until commercialization of thebreeder is 5 to 20 years depending on whichbreeder technology (French or U. S.) is meant.On the face of it, commercial readiness willoccur in 1985, assureing success of the Super-phenix. After that, France plans an aggressiveprogram of breeder deployment, starting a newplant every 2 years for the rest of the century. *The French central utility (EdF) has alreadyordered the first two of these “commercial”plants. Progress on the U.S. plant comparableto the Phenix (the Clinch River breeder) hasstalled, and its technology is outmoded insome respects. Some argue this intermediateplant step should be skipped to go to a com-mercial-size or nearly commercial-size plant.———

*A reevaluation of these plans is apparently underway inFrance following the recent election


The Ieadtime for constructing a conventionalnuclear plant in the United States is 12 yearsand design and construction of a full-scalebreeder prototype under the same ground rulescould take 15 years. Thus, U.S. breeder tech-nology could be commercialized sometime inthe 1990’s, depending on the development se-quence.

The major difference between the Frenchand American technologies is whether thereactor vessel uses a “loop” or “pool” methodof bathing the core with Iiquid sodium coolant.The pool method is simpler, has more thermalinertia, and is considered by the French to bean added safety factor. The loop method ismore similar to conventional reactor technol-ogy and has been tested on an intermediate-scale U.S. breeder used for fuel development(the FFTF). Britain and France espouse the poolapproach; the United States and Japan use theloop method; and the Soviet Union and theFederal Republic of Germany are testing both.

In principle, a U.S. utility could order aSuperphenix reactor now for delivery in theearly 1990’s and in that sense the breedercould be said to be commercially availablealready. But no utility would invest in a centralnuclear plant without reasonable assurance itwould be reliable and could be Iicensed in thiscountry. The licensability of the French tech-nology is an open question.

The RD&D cost of commercializing thebreeder is uncertain because the nationalpolicy for 1976-80 was to not deploy thebreeder. It is also dependent on the demon-stration strategy chosen (i. e., whether to gostraight to a commercial prototype). Estimatesmade by the U.S. program managers in 1975 of$10 billion to $15 billion for commercial dem-onstration should stilI apply.

The obstacles that the breeder programmust overcome before commercialization arenot primarily technical. There is little doubtthat a strong breeder RD&D effort could resultin a reactor that utilities could order in a fewdecades. The questions are economic and in-stitutional and generic to nuclear power. Forthe purposes of this discussion, the economic

questions are less important. Unless thebreeder costs are so high that it is uneconomiccompared to other options, the major concernsare related to light-water reactors. These willnot greatly affect the SPS decision.

Deployment of the breeder is predicated onthe continued expansion of light-water reac-tors. The problems facing the industry arecomplex and difficult as discussed in the sec-tion on conventional nuclear reactors above. Ifthese problems are not resolved, the fission op-tion will be foreclosed, at least as a majorenergy source. Fusion may also be threatened.The breeder exacerbates some of these prob-lems. Proliferation of nuclear weapons will beconsiderably harder to control if breeders areworldwide articles of commerce. While thismight not have a direct bearing on a utility’sdecisionmaking process, the safeguards imp-lemented to prevent diversion might be quiteonerous, and public opinion could be hostile.Health and safety issues will be importantbecause of the plutonium and the operatingcharacteristics of the reactor. Waste disposalwill not be qualitatively different, but the vast-ly greater potential of breeders to producewaste make the problem greater, especially ifdisposal sites are difficult to find. While theseproblems, individually or collectively, neednot be overwhelming, they can all adversely af-fect a utility’s inclination to order a nuclearpIant. As long as a utility has a choice within areasonable economic range, it is likely toselect the less controversial options. Thus,while breeders could in principle supply all theelectric power needed in the 21st century, theymay in fact supply Iittle or none.

4. Fusion.– Of the future energy sourcesconsidered here as competitors to the SPS, fu-sion is the furthest from realization. Fusionconsists of nuclear reactions that are createdby bringing together light nuclei at speedsgreat enough to exceed their mutual repulsiveforce. The result of this reaction is the creationof nuclear energy that is carried off by neu-trons and/or charged particles, depending onthe nature of the reactants. In order to createthis reaction it is necessary to: 1 ) raise thetemperature of the fusion fuel to very high


levels and, 2) confine the fuel for sufficienttime. The criterion to be met by these two con-ditions is that more energy is released by thenuclear reactions than is used to heat and con-fine the fuel that is in a wispy, gaseous form(plasma).

Since the fusion reaction would be rapidlycooled by the reactor walls, containment bysolid materials is not possible. Such an ap-proach would quench the plasma. This dif-ficulty, incidently, would also make a fusionreactor easier to turn off, making it safer thanfission. Two alternate approaches are beingtaken: using a magnetic field in one of manypossible shapes that have been proposed,(magnetic fusion); and using a laser or ionbeam to produce a miniexplosion of the fuel insolid form so that confinement occurs by theinertia of the fuel (inertially confined fusion orICF). The second approach draws on nuclearweapons work for some of its research and ispartially classified. The discussion to followwill center on the magnetic approaches.

Among different magnetic confinement con-cepts—or types of “magnetic bottles” —theleading contender is a toroidal shape calledthe tokamak, after the Russian acronym givenby its inventors. As a reactor, it would be con-siderably more complex than a conventionalpowerplant. The mixture of deuterium andtritium fuel planned for use in first-generationfusion reactors burns at a very high tempera-ture, 100 million 0 C. The natural current in atokamak system is not sufficient for heatingthe fuel that hot, so additional and complexheating systems are required. The fusion corewill be large enough that electrical losses inthe magnets would be a significant drain onthe output of the plant, unless superconduct-ing magnets are developed specifically for fu-sion applications. Other complexities arisefrom the fuel requirements and operating re-quirements. Any fusion system must breed halfits fuel (the tritium component), and tokamaksystems currently under development mustoperate in a pulsed (few hour) mode ratherthan a continuous power mode.

These factors make fusion more complexthan either conventional reactors or breeders.

Particular difficulties in understanding thebehavior of the fusion fuel in its very hot(plasma) state explain why scientists have hadso much difficulty making progress in fusionresearch (which began in 1954).

Fusion is unique among future energy tech-nologies because it has not yet been proventechnically feasible—that is to say, no con-trolled fusion reaction has yet operated in aself-sustaining fashion or produced electricityeven on a small scale. It has a broad range ofpotential applications, e.g., electricity produc-tion, high temperature process heat, syntheticfuel production, and fissile fuel production.

The fusion community can point to a recentstring of successful experiments as evidencethat fusion is on the verge of a scientificbreakthrough. One of the goals is “break-even, ” meaning the achievement of positivenet energy production. DOE expects break-even to be achieved before 1985, and a recentreview by the research oversight board ofD O E9 concluded that fusion was ready tomove from the research stage to the engineer-ing development stage. Nevertheless, theweaker understanding of the principles of con-trolled fusion compared to other energy tech-nologies means that more emphasis is neces-sarily being placed on basic research. Con-sequently, the engineering-related considera-tions that influence commercial readiness andacceptability—that is the technical, eco-nomic, and environmental factors — are moreuncertain than for breeders, solar thermal, PVor SPS.

Despite the high degree of uncertainty,much more can be said about the engineeringfeatures of fusion than was possible a fewyears ago, based on a set of thorough anddetailed engineering studies. Using the toka-mak as a reference system, a powerplant islikely to be in the range of 500 to 1,500 MW,with 1,000 MW being the nominal planningsize. A tokamak fusion reactor would operateas a baseload plant, with capacity factors, con-struction Ieadtimes, plant lifetimes, land,labor, and materials requirements similar to

9ERAB Report (DOE), 1980


conventional nuclear plants. The high-tech-nology core would constitute a substantiallylarger percentage of the total plant than forconventional (or breeder) nuclear plants, andfusion would have some unusual maintenanceproblems that arise from the character of thefusion reaction itself. Since the nature of thefusion core must be considered hypotheticaluntil technical feasibility is proven, the eco-nomics of fusion is perhaps the most uncertaincharacteristic at this time. Two different engi-neering studies prepared at the University ofWisconsin 10 and Argonne National Labora-tory” put the busbar costs at 75 and 44 mills/kW respectively (in 1980 dollars).

Because of the special character of fusion,estimates of the timetable to commercial read-iness vary widely. A recent survey of opinionfound the majority of estimates to fall be-tween 2000 and 2025, with some as early as1990 and a few extending to the 22d century ornever. 2 It appears unlikely that fusion will becommercialized before 2010— the earliest Iike-Iy date for SPS – and the present DOE programis on a schedule calling for “demonstration” in2015, with the dates 1995 or 2000 consideredpossible at increased cost. The DOE programcalls for two steps after breakeven in 1985, thefirst a fusion engineering demonstration in1990 that produces thermal power but no elec-tricity. Pending success with this plant, a fu-sion demonstration plant would be started byabout 2000, that could produce 500 to 1,000MW of electricity. However, more steps arelikely to be needed prior to commercializa-tion. Fusion research is in such an early phasevis-a-vis other technologies that it is difficult todetermine reliably the path to “commercial”fusion.

To be commercialized, fusion must also findpublic acceptability. From an environmental,health, and safety standpoint, the principle ad-vantage of fusion over fission power is that

‘O’’ NUWMAK A Tokamak Reactor Design Study, ” Fusion En-glneerlng Program, Nuclear Engineering Department, Universityof Wisconsin UWFDM-330, March 1979

1‘Argonne National Laboratory, Start;re

“’’Chase Delphi Study on Fusion, First Round Results, ” ChaseManhattan Bank, September 1979

there is no conceivable possibility of a run-away reaction. But first-generation fusionplants will use relatively large quantities oftritium, a radioactive gas harmful to humans.Advanced fusion fuel cycles would greatlyreduce the quantity of tritium that must behandled. To make fusion safe, the problem ofhandling industrial quantities of tritium with-out routine small emissions will have to besolved. There will also be a substantial wastedisposal problem, because the “first wall” ofthe containment chamber for magnetic sys-tems will have to be replaced every few yearsdue to radiation damage. Since the replace-able “wall” may be up to 1-m thick, the quanti-ty of waste could be high, measured in the tensor hundreds of tons per reactor per year. Thismaterial will be highly radioactive and wilI pre-sent a long-term waste disposal problem,though the radioactivity will not be as long-Iived as conventional fission reactor wastes.The amount and lifetime of radioactivematerial can possibly be reduced substantiallyby using other materials for the first wallwithout changing the nature of the fusion reac-tion. Analogous changes for fission reactorsare not possible since the waste materialgenerated is an inherent part of the fuel ele-ment. Finally, fusion carries some proliferationrisk because the energetic neutrons of the fu-sion reaction comprise a high quality sourcefor producing weapons material. It is con-ceivable that unless proper safeguards aredeveloped, a world full of fusion reactorscould be highly proliferation prone. However,there are many other technologies that areavailable or could be available for the samepurposes earlier, more readily, and morecheaply than fusion.

To a degree, fusion may also inherit thepublic acceptance problems of nuclear fission.Fusion is a different technology, with fewer in-trinsic risks but greatly increased complexity.But since it is a nuclear technology, even if itturns out to be relatively benign compared tofission, it may remain associated with conven-tional nuclear power in the public mind.

The greatest uncertainty in the developmentof fusion remains the physics associated with

Ch. 6—SPS in Context • 121

breakeven. Although many of these uncertain-ties can be resolved by small experimentscosting on the order of $1 million to $10million, complete resolution will still require afew large sophisticated experiments, costing inexcess of $1 billion. It should be noted,however, that the nature of the fusion reactiocis such that a demonstration reactor wouId re-quire very little increase in scale or cost fromthese large experiments. The total cost to de-velop fusion to the stage of commercialviability depends significantly on the cost ofthis “hardware” and is projected by DOE to be$20 billion to $30 billion. If more than two ma-jor steps are needed before a commercial pro-totype can be built, the cost will be somewhathigher.

5. Comparisons of Central Electrics. -Becauseeach of these future electric technologies isdesigned for use in a central plant mode, theyare best compared in the context of a utilitycompany’s needs. If each of the different tech-nologies were at the same stage of develop-ment, comparison based on projected powercosts would be the most powerful and appro-priate method of analysis, particularly if allwere close to commercial maturity. But thefive are at quite different states of technicalmaturity — so much so that even the defini-tions used for “commercial” maturity used inthe different programs may be qualitativelydifferent. Lacking information that may take 5to 20 years to acquire, a close look was takenat other characteristics, with particular atten-tion to properties–such as complexity, healtheffects, and safety — which past experience hasshown to be closely related to both capital andoperating costs<

After costs, the most important issue theutilities must consider in deciding to riskcapital on a particular investment in a genera-ting technology is the way in which a plant isexpected to function and its associated im-pacts. Can the proposed technology be suc-cessfully integrated in the grid and meet theassociated requirements for reliability andcapacity? These issues are discussed for theSPS in chapter 9. This section will highlight the

factors most important for the other centralbase load technologies.

Scale of Power Output. – Plants must bedesigned on a scale that can be readily inte-grated into the existing grid at the time of de-ployment. Using the rule of thumb that no oneplant should comprise more than 10 to 12 per-cent of the system’s capacity to guarantee in-tegrity of the grid during a plant failure, thelargest plant that could be presently accom-modated by a single utility in the United Stateswould be 2,500 MW, and that only by the Ten-nessee Valley Authority. (See ch. 9. for adiscussion of this issue.) Cooperative agree-ments among utiIities on the same grid can ex-pand the maximum acceptable size. Currentbaseload plants generate from 500 to 1,300MW. Both fusion and breeder plants are plan-ned to fit closely within this range. Very largepowerplants (greater than 1,500 MW) were therule in fusion planning several years ago, butencouraging new research results coupled withnew interest in smaller powerplants allowedfusion engineering designers to direct effortstoward conceptual designs in line with presentpowerplant scales. Larger plants would meanimproved economies of scale for the breeder(as it would for fusion), but for utility com-patibility reasons (as well as licensability), theprojected size of the breeder has also beenkept below 1,500 MW.

Solar thermal and solar PV pIants achievetheir economies of scale at much lower out-puts–100 to 200 MW maximum. Both canfunction economically at still smaller scales.Photovoltaics are modular and economic at afew kilowatts or less.

Only the reference system SPS appears tohave economies of scale that make it imprac-tical at a size that can be accommodated bythe present utility systems. Whether it could beaccommodated in future utility systems de-pends on the growth of future electric de-mand. Smaller microwave systems or a lasersystem would fit the utility grid more readily.

Reliability and Capacity Factor. – Prior tothe demonstration of a technology, both its

83-316 0 - 81 - 9


capacity factor and its projected reliability aresubject to considerable uncertainty. However,it is expected that breeders will operate muchas conventional light water reactors do today,with capacity factors of 60 to 75 percent andforced outage rates (that is, unplanned shut-downs) of less than 15 percent.

The steam and electric generation parts offusion plants are expected to be similar to con-ventional reactors and breeders. But the fusioncore will be much more complex than thenuclear parts of a conventional or breederplant. One indication of this is that the fusioncore is expected to represent a much largerfraction of the plant investment (50 v. 10 per-cent for nuclear). Because of the vast uncer-tainties surrounding the actual operatingcharacteristics of fusion technology, it is im-possible to predict what capacity factors andforced outage rates are likely to be. It is clearthat to compete with breeders or light waterreactors, fusion should be just as reliable andcapable as they are.

Solar thermal is a steam technology, with abalance of plant that will be similar to, thoughsmaller than, that for a conventional baseloadplant. The solar-thermal part will be chieflyvulnerable to failure of the heliostats or theboiler. The heliostat fields could have trackingor maintenance problems, the boilers couldhave materials and integrity problems due tothe high solar flux. Nevertheless, it is projectedto operate with reliability similar to othersteam technologies —60 to 90 percent.

Solar PV is the simplest technology, withoutsteam systems or moving parts or (necessarily)high solar flux, if flat plate systems prove mosteconomic. Because it is simple, the reliabilityof solar PV is expected to be very high (greaterthan 90 percent). There may be unsuspecteddurability problems with some solar PV cells,however. Although PV are an intrinsically sim-ple technology, it currently has higher materialand manufacturing costs than other alter-natives. Both solar thermal and solar PV havean inherent limitation of plant capacity factor,due to the daily and yearly variation of am-bient sunlight, which differs with latitude and

climate. In the Southwestern United States, thecapacity factor of a plant without storagewould be 23 to 25 percent. Storage for a solarthermal or solar PV plant redistributes the col-lected energy to other times of day, but doesnot appreciably change the amount of energyCoIIected per year per acre of plant area.

The SPS would circumvent the 25-percentcapacity factor limitation of terrestrial solarplants by being exposed in space to directsunlight 24 hours per day all year (except forbrief, predictable eclipses if located in geosta-tionary orbit, or unpredictable cloud cover if alaser or mirror system). The question with SPSis not solar capacity but availability. As withfusion, it is impossible to predict just howreliable the SPS wouId be. As a system it is verycomplicated, involving a massive transporta-tion system, untried satellite technology, andlarge ground systems. Reliability factors ashigh as 95 percent have been predicted for theoperation of the satellite and rectenna com-bined, 13 but they have not taken into accountthe entire SPS system, including maintenanceand repair. Research on transportation andspace platforms will provide considerable in-sight into the expected reliability of thesatelIite.

Complexity. –Given the extreme range ofphysical requirements for a sustained, con-trolled fusion reaction, fusion is clearly themost complex technology under considera-tion, requiring a plasma hotter than the core ofthe Sun, powerful large superconductingmagnets bigger than any yet built, andmaterials problems in a radiation environmentmore severe than that of the breeder. Thereference system SPS is less complex than fu-sion, since it uses more nearly proven technol-ogies. Nevertheless, the overall engineeringand logistics problems of the SPS could makeit an undertaking that approaches the com-plexity of fusion when all the technical hurdlesare considered. It should be noted, for in-

‘” SPS/Utlllty Grid Opera t ions , ” sec 14 o f Boe ing Corp , re -por t No D 180-25461-3


stance, that the SPS as it is described in thereference system could only begin to beassembled as a system after major break-throughs in two other technologies—spacetransportation and PV — are achieved.

The breeder is considerably less complexthan either the SPS or fusion, but is more com-plex than conventional nuclear systems. Themain potential difficulties are the nuclearproperties of the breeder core, the peculiari-ties of the liquid metal coolant, and the poten-tial difficulties of the breeder fuel cycle.Although these factors are incremental addi-tions to the complexity of a nuclear pIant, theyare the driving factors behind the projectionsthat the breeder will cost 25 to 100 percentmore than a light water reactor (LWR).

The solar thermal plant is also a steamsystem that has much of the complexity ofother steam systems, such as coal or nuclear,mitigated by the reduced size of the plant andthe modularity of the heliostat field. Theremay be special problems in having a centralplant boiler at the top of a tall tower, but solarthermal plants appear to be less complex thannuclear, fusion or SPS technologies. Their com-plexity may be comparable to current base-Ioad coal technologies.

Central PV plants have by far the least com-plexity of the alternatives discussed here, fortwo reasons. First, the basic technology is sim-ple, modular, and should be manufacturedcheaply if the experience with mass-producedsemiconductor products holds as expected.Second, the additional technology needed fora central plant is electrical rather than me-chanical or thermal, and is already proven atthe appropriate scale.

Costs. –The cheapest acceptable technol-ogies available in any future time period willbe the ones deployed, so cost is the most im-portant — and most problematic —factor. Twoaspects of technology cost will be discussed.The busbar cost is the cost at which truly com-mercial versions of the various electric tech-nologies will produce power. The opportunitycost is the total cost of RD&D for a technologyfrom inception through the construction of a

commercial prototype pIant. It is the cost oflost opportunities in other areas for which themoney could have been spent. A componentof the opportunity cost is the cost of the com-mercial prototype itself, which is the dem-onstration cost.

The busbar cost is the actual cost of produc-ing electricity with a technology when capitalcosts, fuel costs (if any) and operation andmaintenance costs have been considered. Forcurrent technologies, these costs are well-known and therefore detailed comparisons be-tween technologies are possible. However,even for current technologies the task can bedifficult–witness the debate over whethercoal or conventional nuclear is cheaper. Forfuture technologies, the task is much more un-certain. Therefore, cost estimates of deliveredelectricity are of Iittle use in deciding betweentechnologies in early development stages. Fur-thermore, technologies reach commercializa-tion at different times. Therefore, cost es-timates for one technology are more reliablethan for another, with the most fully de-veloped technologies having the most thor-oughly tested cost data. For example, coalplant costs are well known, but breeder costsare less so, and fusion costs are much less so.Though it is a current technology, the futurecosts of PV for onsite, central, or SPS plants,depend strongly on the future costs and effi-ciencies of PV cells and are consequently un-certain as well. A final note on busbar cost es-timates is that as a technology matures, theprojected cost may fall (as has happened withcomputers) but much more often rises. Thematuration effect of costs during R&D hasbeen particularly borne out in aerospace andenergy technologies.14 15

Although busbar cost estimates are useful inthe research phase to identify cost sensitivitiesand indicate preferred research directions toreduce costs, they become crucial at the

“U S General Accounting off ice, “Need for ImprovedReporting and Cost Estimating on Major Unmanned Satellitel’roject~, ” PSAD-75-190, 1975.

“F W Merrow, S W Chapel, and C Worthing, “A Revtew of(-ost E ~tlmatlon in New Technologies Impllcatlons for EnergyI’recess Plants, ” R-2481-DOE, Rand Corp , 1979


deployment phase. The DOE prepared costestimates for coal, light water reactors, coalgasification systems using combined cyclesystems, LMFBR breeders, peaking terrestrialPV plants, fusion and the SPS (fig. 28). ” Thefigure indicates the high and low ends of therange of estimates for each technology in2000. It shows that capital costs do indeed in-crease with complexity, rising steadily for coal,LWR, LMFBR, fusion, and SPS systems. Costsare also relatively high for the terrestrial PV.Although it is an unlikely circumstance, thechart indicates that alI could cost the same in2000.

OTA prepared estimates that consideredthese future electric technologies including fu-sion (but not combined cycles), in terms oftheir busbar costs in 2010. The resuIts are givenin table 17, using common financial consid-erations, equal capacity factors (65 percent in

“Program Assessment Repor t s ta tement o f f ind ings , SPS Con-cept and Evaluation Program, DOE/E R-0085, 1980

Figure 28.—Levelized Lifecycle Cost of Electricity

Levelized generation cost (1978 mills/kWh)

SOURCE: Program Assessment Report Statement of Findings, SPS Con-cept and Evaluation Program, DOE/E R-0085, 1980.

all cases), and the assumption of baseloadoperation for each technology. As notedabove, these numbers may be indicative butare Iimited in their use because the uncertaintyrange represented by the range of costs meansdifferent things for each different technology.Factors that are small contributors to theestimated costs may have uncertainties thatare substantial (such as nuclear waste disposalcosts) but are difficult to identify and measure.Finally, baseload operation is not necessarilythe most attractive operating mode for solarthermal and solar PV though it provides a basisfor comparison.

RD&D Costs. –One of the most difficulttasks in choosing the wisest course for RD&D isto maintain the proper balance between therisks and the potential payoffs associated witha particular line of research. The goal is tominimize the risk and maximize the payoff. Inenergy research, the risk is associated with theexpenditure of RD&D funds for a project thatcould conceivably fail. The hoped-for payoff ischeap energy. The associated RD&D funds re-quired to pursue some of the future electricoptions under consideration are so great that itis Iikely that not al I can be pursued at an op-timum rate. By according priority to some, op-portunities for payoffs from others will beforegone.

As the matrix of table 16 makes clear, SPSwiII have the highest front-end costs by a con-siderable margin, followed by fusion and thebreeder. The solar thermal and solar PV sys-tems will have lower RD&D costs, in the rangeof $0.5 biIIion to $2 billion.

The costs of the breeder will be large–inthe range of $10 billion to $15 billion—assuming the United States does not changethe present policy of developing domesticrather than foreign technology. But this figureis nevertheless comparable to the front endcosts of other centralized energy technologies.Cumulative RD&D for light water reactors, forinstance, is estimated to have total led $10billion. Fusion’s costs will be the same orsomewhat higher, estimated at $20 billion to$30 billion, including a commercial prototype


Table 17.—Summary Assessment

Prospectiveeconomic-cost Relative Commercialrange a (1 980 $) environmental Engineering/ readiness

Technology (mills per kWh) costs Scientific technical Commercial (year)

Satellite power system . . . . . . . 80-440 Unknown Proven b Unproven — 2005-2015

Solar photovoltaic with storage 65-86 Negligible Proven Proven Unproven Late 1980’sSolar thermal with storage. . . . 62-89 Negligible Proven Proven ● Unproven Late 1980’sBreeder reactors . . . . . . . . . . . . 58-73 Substantial Proven Proven Proven 2000Fusion . . . . . . . . . . . . . . . . . . . . 44-75C Moderate- Unproven — — ?

substantial

LWR-201O . . . . . . . . . . . . . . . . . . 58 Moderate- P r o v e n – Proven Proven Operationalsubstantial

LWR-1980 . . . . . . . . . . . . . . . . . . 47 — — — — —

aPlant starting in 2010.bEnvironmental impact still unknown, other aspects generallY accepted.CNote this range reflects differences between two studies’ estimates (footnotes 1 Cl and 11 On p 120).aMassive scale-up of known technologies.

SOURCE: OTA working paper.

plant. Fusion and the breeder may thus com-pete with each other for R&D funds.

The costs of the SPS will be substantiallyhigher than for any of the other options, at anestimated figure of $40 biIIion to $100 bilIion. 7

The high number assumes all space develop-ment and pIant investment costs are allocatedto the SPS (see ch. 5), while the lower numberassumes the total cost but allocates $60 bill ionto other space programs that could benefitfrom the same technical capability.

The SPS RD&D cost is so high that commit-ment to it could foreclose fusion or thebreeder. As such, a decision at some point inthe future to commit to the SPS would be adecision with potentially far-reaching con-sequences.

In fact, the SPS is the first proposed energyoption whose RD&D costs enter the budgetaryrange that has previously been limited to veryhigh-technology, high-cost national defenseprograms such as the MX missile system. Thatsystem, as proposed, will cost” $34 billion to$50 billion. Thus, from a policy point of view,the SPS is qualitatively different from anyother proposed long-range energy solution.

Institutional Impacts. — Neither fusion norfission requires much that is new institution-ally because their size, health and environ men-

170TA Workshop on Technical OptIons, December 1979

tal impacts, and operating structure are similarto current LWR technology. As technologiesused in the centralized mode, the solar tech-nologies will not require different institutionalattention than do any other peaking or inter-mediate plant. As dispersed plants, they arelikely to be subject to a much different regula-tory regime’ 8 and utility structure that encom-passes a much broader technological scopethan is now the case.

SPS, however, because it is a space systemrequiring very high capital investment, wouldlikely involve an institutional structure veryunlike those in use today in the utility industry(see ch. 9). The main point is that the utilitiesare unlikely to want to invest directly insatellites, or perhaps even rectennas. It willcreate far fewer regulatory and capital prob-lems for the utilities for them to buy powerfrom a single SPS corporation and incorporateIt directly into their grid. A national S P Smonopoly would necessarily be federally, aswelI as internationally regulated (see ch. 7).

National Security Risks. – Both of the nu-c I ear technologies u rider consideration(breeders and fusion) can be used to generateweapons material and therefore they carrysome risk of increasing nuclear weapons pro-liferation. The terrestrial solar technologies—.—

“Office of Technology Assessmentr U.S. Congress,“Decentralized Electric Energy Generation Systems,” upcomingreport, fal I 1981


seem to have purely beneficial national securi-ty effects, however. They can be exported andused around the world for peaceful purposes.Because they would be used in relatively smallunits, they would be much less vulnerable thanany larger unit and less of a military risk for acountry selling the technology.

SPS would have indirect military potential,largely from the technology that would bedeveloped for space transportation and spaceconstruction. However, the system itself wouldserve as a poor weapon. The question of vul-nerability of an SPS system to nuclear or otherattack is a different issue. On the whole it is Iit-tle more vulnerable than any of the larger ter-restrial electricity options (see ch. 7).

Economic Risks of RD&D Failure.— Ingeneral, the risks of failure are tied directly tothe opportunity costs for the different centralelectric technologies. Therefore, the risks arehigher for fusion and SPS than for any of theothers. However, the financial risks of failuremay be mitigated if some of the RD&D costsare recoverable for other uses. For example,the space spinoffs from developing the SPScould be significant (an upgraded shuttle,space platform technology, an orbital transfervehicle technology, high powered microwaveor laser transmission devices), which wouldreduce the economic risks. Here, as in thestrictly research phase of an SPS program, it isvery important to be cognizant of other spaceand energy programs that could benefit fromdollars spent on SPS research and vice versa.

Safety and Health Risks. –OTA pursued noindependent study of health and safety risks ofthe five technologies. This assessment hastherefore relied on the work of Argonne Na-tional Laboratory that was funded by the SPSoffice of DOE. ’9 The reader is referred to itsreport for a comprehensive treatment of theproblem (see also app. D). The Argonne studyattempted to quantify risks in terms of thenumber of fatalities that would occur per yearfor a specified plant output (see fig. 29). Someof the issues are unquantifiable, and for the

‘(’G R Woodcock, “Solar Power Satellites ~nd the Evolutionof Space Technology, ” presented at A I AA Meeting, May 1980

Figure 29. —Quantified Health Effects

77

10.0rOperation andmaintenance, publicOperation andmaintenance, occupationalConstruction, mfr.

LWR CG/CC LMFBR CTPV SPS MCFusion& cc

SOURCE Program Assessment Report Statement of Findings, SPS Conceptand Evaluation Program, DOE/ER-0085, 1980.

SPS and fusion, most of the issues are in thiscategory. The difficulty of quantifying issuesfor SPS and fusion is a function of the uncer-tainties about the final configuration thesetechnologies will take as well as the lack of ex-perience with them upon which to base esti-mates of fatalities. This is an area that needsconsiderable further study, not only for SPSbut in every other comparative study of energytechnologies. The major needs are to put allthe data on as common a basis as possible andto quantify risks where they are currently un-quantified (see ch. 8 for a summary of SPShealth and safety risks).

Environmental Risks. –As with health andsafety risks, OTA attempted no independentanalysis and has relied on the comparativeassessment study of Argonne National Labora-tory. 20 Table 18 summarizes the most impor-tant environmental effects for each of thetechnologies under study, plus coal. The nu-clear technologies have been grouped togetherbecause their effects are common to all thenuclear technologies.

‘“L J H abegger, J R G a s p e r , a n d C D B r o w n , “ H e a l t h a n d

Saft’tV Pr~~llmlnary C o m p a r a t i v e A s s e s s m e n t o f t h e SPS a n d

O t h e r F nt’rgy Alternatlve~, ” DOE report No DOE/E R-0053, April

1 98()

Ch. 6—SPS in Context . 127

Table 18.—Major Environmental Risks

Coal Nuclear SPS

Air pollution Catastrophic events Atmospheric changesAtmospheric changes Land use Bioeffects from microwaves,(CO 2, particulate) Thermal discharge waste lasers, reflected light

Esthetic deterioration disposal Electromagnetic disturbanceLand use Land use


Other factors. – How well would SPS com-pete with other baseload electric tech-nologies? This question can ultimately beanswered only in the context of overall de-mand for electricity, considerations that aretaken up at the end of this chapter. However, ifdemand for electricity is such that SPS may beneeded to supply a portion of that demand,then the competitive position of SPS vis-a-visthe other technologies will depend primarilyon its being cost competitive, and presentingcomparable health or environmental hazardsto the other technologies. Other utility con-cerns such as its reliability and rated capacityfactor have direct and obvious economic im-pacts that are subsumed in the condition of itsbeing cost competitive. It is too early to tellwhether SPS can compete effectively. What isclear, however, is that factors beyond thescope of control of an SPS program may deter-mine more effectively whether SPS is com-petitive than the important concerns overcosts or health and environmental effects. Theeffects of reduced coal useage are examinedbelow. However, before the United Statesneeds to decide whether it is prudent to con-tinue or expand coal burning (c 2000), it mustmake a decision about the use of breeder reac-tors (c 1990). If we institute a strong breederprogram, then SPS is less likely to be neededthan otherwise, simply because breeders areapparently cheaper to build and operate thanthe SPS. They have the further competitive ad-vantage that they strongly resemble LWRS,both in operating characteristics and in health,safety and environmental impacts.21 Thus, util-ities are more Iikely to purchase breeders thanto take on a brand new technology whose ma-

“E. P Levine, et al , “Comparative Assessment of Environmen-tal Welfare Effects of the Satellite Power Sytem and OtherEnergy Alternatives, ” DOE report No DOE/E R-0055, April 1980

jor resemblance to terrestrial technologies isthe fact that it produces electricity. However,perhaps more important is the fact thatbreeders could play a significant role in sup-plying electricity 10 to 20 years before the SPS,thus giving them an automatic competitive ad-vantage.

Although the fusion program has not yetproven that it is possible to generate moreenergy than is fed to the fusion process, the fu-sion community is confident that the produc-tion of electricity from fusion is a matter ofcontinued R&D. The costs are more uncertainthan for SPS. However, fusion has a strongfollowlng inside and outside the fusion com-munity. Furthermore, the utilities are alreadyactively pursuing fusion studies. Therefore, iffusion’s costs turn out to be competitive withSPS, it too may be chosen over SPS because ithas a strong following and because beyond thefirst wall, it is similar to other nuclear optionsin the way in which it generates electricity.However, it may not be capable of making asignificant impact on the supply of electricityuntiI welI after SPS, i.e., not until 2030 or later.

Because several proposed versions of theSPS are designed to use PV cells, a terrestrialPV system constitutes an obvious comparisonto the SPS. The satellite or SOLARES groundsite would receive continuous sunlight. A ter-restrial system, however, receives constantlyvarying sunlight. Table 19 compares the peakand total annual insolation in space, at aSOLARES ground station and in Boston andPhoenix for an optimally tilted flat-plate, non-tracking solar collector. Therefore, a terrestrialPV in Phoenix the size of a reference systemrectenna would, in theory, be capable of pro-ducing as much electricity on a yearly basis asthe reference satellite. However, the output of


Table 19.—Terrestrial and Space Insolation Compared

Average annual Area needed to produce 1,000 MWPeak insolation (per insolation (per (per continuous output on Earth

square meter) square meter) (17-percent efficiency cells)

Space. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3 kW 11,800 kWh 10 km2

SOLARES GND Station (29° latitude). . . . . . . . . 1.3 kW 9,734 kWh 6 km2

Boston. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.8 kW 1,430 kWh 44 km2

Phoenix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.0 kW 2,410 kWh 26 km2

Equivalent rectenna area for referencesystem—35° latitude. . . . . . . . . . . . . . . . . . . . . — — 28 km2

—.SOURCE: Office of Technology Assessment,

such a central terrestrial system would be sub-ject to short-term and seasonal variations inoutput due to fluctuations in insolationbrought out by cloud cover. This effect is il-lustrated in table 20 for the Boston andPhoenix areas. The daily insolation for themonth of December is 28-percent less than forthe average month, resulting in 28- percent lessPV output for the same sized array. Phoenix,by contrast, experiences average insolationvalues only 14 percent lower than the averagein July, its month of lowest insolation.

Decentralized Electrical Generation

Although technologies that are capable ofproducing electricity in a dispersed mode maynot be direct competitors of centralizedtechnologies, they will compete for a percent-age share of overall electricity supply in thiscountry and the world. In 1977, the residentialsector of the electrical market constituted 36percent of this Nation’s demand for electricity.If a significant portion of this demand as wellas part of the demand for commercial and in-dustrial consumption can be met by dispersedtechnologies such as solar PV, wind, andbiomass at costs that are competitive with cen-tralized electricity, then the demand for cen-trally produced electricity will drop. Low de-mand for centrally produced electricity will inturn reduce the need for new, large-scalegenerating technologies and place them in apoor competitive position with respect toproven technologies. Thus, it is of considerableinterest to investigate the role that dispersedelectrical technologies may play in the Na-tion’s energy future.

Dispersed modes of generating electricityare first and foremost attractive in remoteregions where the electricity grid has not yetpenetrated. It is in these areas where windmillsand PV, with storage, are now being installedeven though their cost is high relative to theprice of grid-supplied electricity.

As experience with these technologiesgrows, and their price decreases due to deepermarket penetration and increased commensu-rate production, they are likely to penetrateareas that are now served by the utilities. Sucha shift will be aided by the Public UtilitiesRegulatory Policies Act of 1978 (PURPA) thatrequires utilities to purchase electricity fromrenewable-based powerplants at their avoidedcost of power. To date, State regulatory com-missions have established prices that are equalto, or higher than, the retail price of electricity.If this practice should continue into the mid-1980’s, onsite electrical generating systems willnot only provide energy for their owner’s use,but will become income generators as well.

This shift will be further aided by the attrac-tiveness of modular units that allow a home-owner or community to become relatively self-reliant and independent of large-scale generat-ing systems over which they have little control.Additionally, onsite systems can be erectedrapidly and incrementally, allowing a closematch of supply to local demand. Under suchconditions, it can be expected that there wouldbe a rapid increase in demand for small-scalesystems.

The role of dispersed electrical generatingtechnology in the Nation’s electrical supply is


Table 20.—Terrestrial Insolation at Different Latitudes and ClimatesBoston: Latitude 42.2

Jan. Feb. Mar. Apr. May J u n e - J u l y Aug. Sept. Oct. Nov. Dec.

kWh/m 2 3.4 3.7 4.1 4.0 4.4 4.3 - 4.6 4.4 4.4 4.1 3.0 2.8kWh/m2/month 104 104 126 119 135 129 142 137 131 126 90 85

Total insolation per year 1,430 kWh/m2

Average daily insolation: 3.9 kWh/m2

Phoenix: Latitude 33.3

Jan. Feb. Mar. Apr. May J u n e - J u l y Aug. Sept. Oct. Nov. Dec.

kWh/m2/day 6.0 7.0 7.4 7.5 6.6 6.2 5.7 6.2 7.0 7.3 6.7 6.0kWh/m 2/month 184 195 228 225 204 186 178 185 218 227 200 185

—Total insolation per year 2,414 kWh/m2

Average daily insolation: 6.6 kWh/m2

SOURCE: Solar Photovoltaics: Applications Seminar, Planning Research Co

the subject of another OTA study that willdiscuss the full array of dispersed electricaltechnologies: wind, PV, and biomass. However, because much of the technology for con-structing space-rated solar cells will be ap-plicable to terrestrial applications and viceversa, this report explores the possible role ofdispersed PV systems in filling part of thiscountry’s electrical needs in the time frame ofthe SPS.

Dispersed Photovoltaic Systems. —The mostimportant single characteristic that makes PVof considerable interest for dispersed uses istheir relative insensitivity to economies ofscale for generating electricity because PV aremodular, allowing considerable flexibility intheir location. Economies of scale are very im-portant in their production, however. The pres-ent high cost of PV (about $7/peak watt) islargely due to a very small production capaci-ty. About 4.5 MW (peak) of terrestrial capacitywere produced globally in 1979, by only adozen manufacturers. Demand exceeds sup-ply, however, even at $7/peak watt and thusthe market will surely expand, especiallyas new manufacturing techniques allowingcheaper PV are developed. All indications arethat continued reduction in price in line withDOE cost goals will accelerate the demand forPV cells for all applications and in particularfor dispersed systems that are either con-

nected to the utility grid or stand alone.Meeting this cost goal is important for the SPS,which in the reference design, is highly sen-sitive to PV array costs (34 percent of satellitecosts).

The total penetration of PV and other decen-tralized energy technologies into the residen-tial, commercial, and industrial sectors of theenergy economy will depend on a number ofinterrelated factors in addition to cost. Thefollowing summary indicates the most impor-tant ones.

● Average Available Sunlight. –The bestareas for dispersed PV are the same oneswhere centralized applications are mostplausible, i.e., in desert climates such asthe Southwestern United States. However,the variation of regional average insola-tion across the continental United Statesis less than a factor of two. Changes fromyear to year are considerably less. Both ef-fects are smaller than variations in energyconsumption and price patterns. Thus,regional or annual insolation variationsare not likely to be a strong determinantof PV penetration. This will be even moretrue in areas where biomass and windsystems can work in complementaryfashion with PVs.


●

●

●

●

Storage. – Advances in storage technologycould have a significant effect on the mar-ket penetration of PV systems, particular-ly for remote and stand-alone applica-tions. It is generally agreed, however, thatlow-priced storage, if it is ever developed,is a decade or two away.The Use of Centralized Photovoltaic Sys-tems. — Using PV for peaking or inter-mediate generating capacity will enhancethe development of low-priced PV cellsand the auxillary equipment (mountingpanels, inverters, etc.) and speed the in-troduction of dispersed PV systems tomarginal areas (i. e., areas where the cen-trally generated electricity is cheaper thanonsite generation).Conservation. –Conservation has alreadyresulted in important reductions in per-capita energy use. In the Washington,D. C., area for example, use of electricity isincreasing by only 1.4 percent a year,22 asharp contrast to the 7 percent yearly in-crease in consumption that was commonin the mid-1 970’s. Continued price in-creases for energy will increase the desireto conserve energy and make the totalneeds of a residence, for instance, muchless. The Virginia Electric Power Co., forexample, reports that in its service areaall-electric homes, used about 24 MWhr/yrin the mid-1 970’s, but consumed only 19MWhr for 1979,23 a 20-percent drop. De-creases in total consumption make itmore likely that PV systems can be sizedto meet the needs of the residential sec-tor<

Other Dispersed Sources of ElectricalPower. –The acceptance of wind and bio-mass for dispersed electrical generation,or as substitutes for electricity, may en-hance the desire for photovoltaics as indi-viduals and the utilities become accus-tomed to working with dispersed sources.However, if other sources failed to make asignificant impact because they were ex-pensive or because they didn’t work well,

?>wfa5h;ngton Post, Mar 25, 1981, P D-9“Washington Post, June 23,1980, p B-1

●

●

●

they could have the opposite effect on theuse of PVs.Cost of Photovoltaics. – Single-crystalsilicon cells are highly energy intensive.Thus, the energy cost of producing them ishigh, and if energy prices increase, thecost of the cells will be higher than theDOE goals. New production techniquesfor amorphous silicon or other materials,however, may lead to less energy inten-sive cells, and the problem could beavoided.Reliability y. –One of the major reasons forpreferring centralized power generation isthe high reliability of electrical service.Dispersed systems must be reliable inorder to capture a significant portion ofthe electricity market. The PV themselvesare extremely reliable. However, the asso-ciated equipment is subject to a higherfailure rate. Market penetration willtherefore depend on a highly reliableproduct and effective, timely service torepair failures.Institutional Effects. – PURPA regulationswiII enhance the use of dispersed-systems.If these regulations are retained and ifthey are carried out effectively on thelocal level, then they will be effective inspeeding the introduction of dispersedelectrical capacity. However, a number ofnegative effects (e. g., low reliability, highcosts, etc.), could cause such regulationsto be repealed if they are found to workinefficientIy.

In summary, it can be said that the future ofdispersed electric systems, and PV in par-ticular, is subject to considerable uncertainty.If cost goals are met, and the effect of theother factors is positive overall, then dispersedelectrical systems could make a significantcontribution especially in a future in which thedemand for electricity is relatively low. Astable 21 illustrates, the cost per kilowatt-hourfor grid-connected PV systems, though subjectto considerable uncertainty, is competitivewith baseload systems. By combining severaldifferent kinds of dispersed sources of elec-tricity (e.g., wind, PV, and biomass), the pros-pects for dispersed PV sales becomes even


Table 21.–Costs of Onsite Photovoltaics (1980¢/kWh)

H o u s e h o l d Industry

Without storage With storage* Without storage With storage*

Boston Phoenix Boston Phoenix Boston Phoenix Boston Phoenix

Roof replacement. . . . . . . . . . . . . . 3.0¢ 1.8¢ 9.0¢ 7.O¢ — —Flat on roof . . . . . . . . . . . . . . . . . . .

— —3.9¢ 2.3¢ 9.9¢ 7.6¢ — — — —

Columns on roof or ground . . . . . . 8.3¢ 4.9¢ 14.7¢ 10.4¢ 8.O¢ 4.7¢ 18.9¢ 12.9¢

NOTE: These costs were developed assuming photovoltaic arrays costing $35/m2 and 17-percent efficiency in space (18 percent on ground). Further details of theassumed systems can be found in app. B.

● Assumed a 80-percent capacity backup generator,SOURCE: Office of Technology Assessment.

stronger than when used alone. As in the caseof the baseload technologies, these figuresmust be seen as indicative of the range of coststhat may be attained and should not be used asa basis for comparison at this time. Con-siderable development wilI be needed to deter-mine whether the various cost goals can bemet.

Implications

Introduction

The discussions just completed illustratethat the future of the SPS, assuming it can bedeveloped technically, depends on a variety offactors. These include the future demand forelectricity and how SPS compares with othersupply technologies. There are two questionsto be answered: 1) is the SPS necessary at all?2) if so, when do we need it? The section on de-mand showed that future electricity needs arehighly uncertain and are dependent on techno-logical developments that can profoundly in-fluence the costs of various end use technol-ogies. The section on supply contained discus-sion of several technologies that would com-pete, partially or completely, with the SPS tosupply electricity for the long term. The sec-tion gave criteria for choosing between thesetechnologies and the range of uncertaintyabout their potential success. From the discus-sion it is clear that a variety of factors beyondpurely technical success will determine whichsupply technology(ies) wiII emerge.

To see this more clearly, OTA chose threehypothetical U.S. energy futures in order to ex-amine possible future supply mixes. They werechosen to span a wide range of possible elec-

tricity demand scenarios for 2030. The lowestassumes no change from our present end-usedemand for electricity, the highest uses the1979 Energy Information Administration (E IA)high projection for 2020 extrapolated to 2030,and the mid-level is halfway between. Thesefutures were chosen as an exercise to illustratethe way various technologies might be usedand the constraints placed on this selection.OTA does not treat these demand levels asforecasts of what will occur, but as a plausiblerange of future end-use demand.

The extremes of the three scenarios arecharacterized by zero growth in electricity de-mand for the low scenario, and an averagegrowth of 2.8 percent per year for the highscenario from 1980 to 2030. The growth in thehigh scenario is not steady, however, but startsat 4.1 percent in the 1980-95 time period, anddeclines to 1.9 percent by the end of the sce-nario in 2030.

The low scenario represents a conservation-oriented energy strategy, in which the in-creases in industrial output and residential andcommercial space are offset by improved effi-ciency of electricity use for industrial proc-esses and drives, and residential and commer-cial heating, air conditioning, lighting, and ap-pliances. The end-use electricity level in thelow scenario, taken from the CONAES sce-nario A, assumed electricity demand at a con-stant level of 7.4 Quads for 1980 to 2010, andextrapolated the same constant level to 2030.That level is very close to the actual end-useelectrical consumption in 1979 which was 7.6Quads. The total primary energy consumption


in the CONAES scenario A is 74 Quads, com-pared to actual use in 1979 of 78.9 Quads.24

The high scenario represents a major expan-sion of the use of electricity in all sectors. Thescenario is taken from the E 1A Series C projec-tion from the Long-Term Energy Analysis Pro-gram. The total primary energy use in thisscenario is 169 Quads. The scenario projects amajor shift in residential fuel use, with elec-tricity supplying 60 percent of all residentialneeds and 55 percent of residential heating.(Water and space heating alone are projectedat 8 Quads end-use electricity in 2020.) Elec-tricity is expected to provide 70 percent of thecommercial energy demand in 2020. In thisproject ion, EIA forecasts that the industrialsector wilI grow faster than any other sector,and that industrial use of electricity will tripleor quadruple by 2020. Total energy use in theindustrial sector in the scenario is 63 Quads in2020. Electricity’s share of the industrialenergy sector rises from 11 to 20 percent. Thedominant supply technologies in the scenarioare coal and nuclear, with coal providing 60percent, nuclear 33 percent, and hydro andother renewable the remainder. The E 1A sce-nario was extrapolated to 2030, using the sameelectric growth rate as assumed in 2010 to2020, namely 1.9 percent. According to the ex-trapolation of this scenario, the total energyuse in 2030 is 196 quads and the total electri-city use is 30.2 Quads (end use).

The middle scenario is chosen to be the mid-point between the high and low scenarios ateach of the decades projected. The end-usefigures for each of these three scenarios aregiven in table 22.

OTA does not suggest these demand levelsas forecasts of what will occur. These futures

24[ner~y jn Trans;tjon, OP c I t

Table 22.—Range of Energy Demand in 2030

End-use electrical Primary totalScenario (Quads) energy (Quads)

High . . . . . . . . . . . . . . 30.2 196Mid . . . . . . . . . . . . . . . 18.8 135Low . . . . . . . . . . . . . . . 7.4 74


were chosen to illustrate the way various tech-nologies might be used and the constraintsthat might be placed on their selection.

To characterize the mix of supply technol-ogies possible under these scenarios, a numberof questions was addressed. Among thesequestions were the numbers and kinds of tech-nologies that would contribute to the supplymix under the various scenarios, the maximumreasonable SPS contribution under each sce-nario, the most likely technologies to replaceSPS were it not deployed, and the relative im-plementation rates of the various technologiesunder different demand conditions. The exer-cise carried the simplifying assumption thatone technology could be substituted foranother These questions cannot be answeredprecisely, but their discussion leads to in-teresting insights into the potential role of SPS.

Low-Demand Future

For this case, end-use energy demand forelectricity is selected to be 7.5 Quads (today’slevel). A zero electric growth future is likely tobe the result of substantial conservation –probably resulting from high energy prices —and the failure to develop end-use technol-ogies that use electricity at a lower net costthan technologies using liquid or gaseous fuelsand direct solar. The principal feature of thisfuture is that electricity demand can be satis-fied without SPS, fusion or breeder reactors.The supply potential of coal, hydro, groundbased solar (including wind) and conventionalnuclear would be more than sufficient to meetdemand Even if coal were to be phased outdue to negative findings about the CO, build-up, its share could probably be absorbed byother sources. Zero growth in electricity de-mand gives the nation considerable time fordeveloping new technologies.

In this situation utilities would only need toreplace retiring plants. Therefore they wouldhave considerable latitude in choosing tech-nologies. Further, a zero growth rate would notfavor large plants because they would add toomuch capacity at one time. Therefore, small-scale, dispersed technologies may play a majorrole in this future. If any of the new tech-


nologies under discussion are introduced theywill have to appear in relatively small in-crements in order to maintain system reliabili-ty. For example, one could expect SPS to pro-vide no more than 1 to 2 Quads at any giventime to the 7 to 8 Quad total. This would actstrongly against an SPS the size of the ref-erence system since it would only require 7 to15 units of 5,000 MW at a 90-percent capacityfactor to supply this much energy. Thereforedeployment of any SPS would depend on an in-ternational demand for electricity and/or thedevelopment of much smaller units than thereference system (perhaps on the order of 500MW). A similar argument could be made aboutfusion and breeder reactors, although currentdevelopment plans show the size of eventualcommercial plants to be 1,000 MW or less.

In summary, a scenario that shows little orno increase in electricity demand for the nextseveral decades does not appear to be attrac-tive for accelerated SPS development, particu-larly of the reference system. At the same time,development of other central, baseload supplyoptions ultimately competing with SPS couldalso be slowed. The choice among these, ifneeded at all, would primarily depend onwhich ones could most economically be de-veloped in smaller sizes.

Middle Demand Future

In this case net electricity demand reachesabout 20 Quads in 2030 representing about a 2-percent growth rate per year that is close tothat which the Nation is now experiencing.Although this is about 2.5 times current elec-tric energy demand, it too could be met with-out using the SPS, fusion or the breeder reac-tor. For example if two-thirds of the 20 Quadswere produced by coal, it would require a tri-pling of present yearly production, which iswithin the Nation’s capability. Current esti-mates of domestic uranium reserves are suffi-cient to supply another 6 Quads in 2030. In ad-dition, a major contribution from terrestrialsolar (wind, onsite PV) can be expected to helpmeet increased intermediate and peak loaddemands that coincide with solar peaks (spaceheating and cooling). If growth continues past

2030, this mix may be insufficient. Yearly coalproduction could probably not be expandedtoo much beyond this (tripled) level withoutstraining other sectors of the economy, and by2030 the Nation may be near its uranium re-source limits. Therefore, to ensure supplybeyond 2030 and to replace retiring nuclearplants, some level of new, centralized tech-nologies would probably be needed.

If coal and conventional nuclear remain ac-ceptable, it is not likely that all three of themajor centralized technologies under develop-ment would be needed. The contribution theycould make by 2030 would be small because ofthe time needed to bring them on line and thefact that they would be starting from a zerobase sometime near 2010. A 10-percent con-tribution to 20 Quads would require anywherefrom 60,000 to 100,000 GW, depending oncapacity factor. Unlike the low demand future,this would allow SPS units of up to 5,000-MWsize to be added if continued growth past 2030is expected. A 2 percent per year growth ratemeans about 0.4 Quad/yr added at that time.This could be supplied by three SPS plants peryear at the reference design size, in addition tobaseload units to replace retired pIants. This isstiII a small enough increment that smaller SPSpIants appear to have an advantage. In addi-tion, this demand increment is still not toolarge to rule out its being met by onsite solar,wind, and centralized solar. All have muchlower energy densities than fusion or breeders,however, and eventually their contribution willbe limited by available area. About 25 m2 arerequired to supply a continuous kilowatt ofsolar electricity assuming PV conversion effi-ciencies of 20 percent. The entire 0.4 Quadcould be supplied by about 125 mi2, not anunreasonable area.

If coal is not acceptable because of C02

then there will have to be a substantially largercontribution by the newer technologies. In thiscase it is plausible that all three, plus substan-tial ground based solar, would be needed.Such a replacement could be achieved withthese new technologies but it would be asizable effort. If coal supplied just half of theelectricity in the case discussed above, about


10 Quads of new electric energy would have tobe found, requiring 300 to 500 GW. If newplants were on the order of 1,000 MW in size, aconstruction rate of 15 to 25 per year would beneeded assuming they were first available in2010. Under this future of constrained coal,then, there would appear to be sufficient de-mand for al I technologies to be introduced at arate that would pay for their development in areasonable period. Also, it is not Iikely that anyone technology wouId be relied upon to supplythe entire 10 Quads at the end of this 20 yearphasing-in period. An even three-way split, forexample, would mean that SPS would supplyabout 100 to 150 GW by 2030.

High-Demand Scenario

This future assumes a final demand for elec-tricity of 30 Quads (about four times the cur-rent level), meaning a growth rate of about 2.8percent per year. At that rate, about 0.8Quad/yr would be added in 2030. If oneassumes an increase in net conversion effi-ciency from today’s 29 to about 35 percent andan increase in capacity factor from 42 to 55percent, then this total demand could be metby an installed generating capacity aboutthree times today’s figure. Efficiency andcapacity factor will almost certainly have toincrease if a 30-Quad demand is to be met.Total system capacity would be in the range of1,200 to 2,400 GW (1,800 GW at 55-percentcapacity factor).

To be able to supply this much electricenergy, all technologies would probably beneeded. Further, larger plants are likely since ademand increment of 0.8 Quad/yr would re-quire about 40,000 to 50,000 MW of new ca-pacity per year. Therefore, addition of plantsranging from 1,000 to 5,000 MW would notcause any significant short- or long-run over-capacity problems. Because of the largeamount of capacity needed, conventional nu-clear and coal will probably be able to supplyonly about two-thirds of the total (i. e., about1,200 GW) before they reach the limits dis-cussed above. Thus, about 600 GW must besupplied by hydro, ground based solar, geo-thermal, and some combination of SPS, fusion

and breeders. Breeders are likely to supply thebulk of this by 2030, provided they are accept-able, since they are the closest to commercialreadiness. Even so, as much as 200 GW of SPScould be needed by 2030. The SPS develop-ment would have to be accelerated if it is tomeet a goal like this. The same holds true forfusion, which could also be required to supplyaround 100 GW by 2030.

The mix of technologies will be determinedsubstantially by constraints such as environ-mental concerns, capital, land and water avail-ability, materials Iimitations and labor require-ments. For example, limited water would favorSPS and ground-based solar PV. Limited cap-ital, however, would favor the least capital-intensive technologies such as coal and actagainst the SPS. In any event, these constraintswill be very important at this demand levelbecause of the large number of powerplantsneeded

If coal must be phased down or eliminatedthen even larger demands will be put on thenew technologies. For example, if coal andconventional nuclear couId only meet one-third of the demand, an additional 600 GW ofcapacity would be needed. In this case it isprobable that an all-out breeder programwould be needed. This should not affect theSPS– in fact, more satellites may be needed–but it could actually reduce fusion’s contribu-tion since it is a competing nuclear technol-ogy. The terrestrial, onsite solar contributionwill have to be large in either case but is veryunlikely to be able to supply even one-half ofthe 30 Quads. Even 20 percent of the demandwould require a very large deployment of PVsystems — nearly 400 GW of dispersed gen-erating capacity.

Conclusion

The size of future electric demand will bethe major determinant in the amount of SPScapacity installed, assuming successful de-velopment and competitive price. Table 23shows estimates of the upper range of SPScapacity available for each future for the caseof fulI coal development and coal phaseout.


Table 23.–Upper Range of SPS Use (in GW)

Future (Quads) With coal Without coal7.5 0 0-30

20.0 0-60 100-20030.0 100-200 100-200


In addition to determining the upper rangeof the contribution of SPS the demand leveland rate of growth will also determine thepreferred unit size. For the low scenario,smaller plants would be preferred since over-capacity problems caused by adding too muchat once would probably more than offset gainsmade by any economy of scale. For the upperfuture, however, for even the largest SPS pro-posed plant size, it is unlikely that too muchcan be added at once for any reasonable con-

struction schedule. The mid scenario, however,gives somewhat ambiguous results, althoughthe smaller size SPS systems appear generallyto be more desirable.

For the first two scenarios it is unlikely thatalI three major, centralized supply technol-ogies will be needed simultaneously, even ifcoal cannot be used. Onsite, dispersed solarwill be able to make up a larger percentage ofthe needed capacity and could eliminate theneed for any new centralized technology in thelow demand case. In all cases, coal can be thedominant source and continue in that role forseveral years past 2030. Finally, as the demandfor electricity increases,pacity mix will becomependent on physical andcause of the sheer sizequirements.

THE EFFECTS OF SPS ON CIVILIANSPACE POLICY AND PROGRAMS

The effects of SPS development on the U.S.civilian space program would be great, thoughtheir precise type and magnitude would de-pend on the kind of SPS built, the overallspeed of the development program and thestatus of space capabiIities at the time. An SPSprogram would stimulate more rapid develop-ment of space transportation, large-structureassembly and manned-mission capabilities,and automated operations. SPS developmentwould also have a bearing on national spacepolicy and institutional structures, both Gov-ernment and private sector. The followingdiscussion will examine four areas: 1) spacepolicy, 2) current and future space projects, 3)institutional structures, and 4) indirect effectsand “spin offs.”

Space Policy

The Nation’s space policy is a reflection ofbroad national goals. The principles guidingthe U.S. civilian program were first enunciatedin the 1958 National Aeronautics and SpaceAct, and have been periodically reaffirmed

with minor modification

decisions aboutmore and morelabor constraintsof the capacity

ca-de-be-re-

and changes of em-phasis. The 1958 Act states that “activities inspace should be devoted to peaceful purposesfor the benefit of all mankind,” to promote the“general welfare and security of the UnitedStates “ The Act specifies that civilian ac-tivities shall be directed by NASA, and mili-tary/defense operations by the Department ofDefense. The specific aims of the space pro-gram include: expansion of knowledge, im-provement of space transportation, “the pres-ervation of the role of the United States as aleader in aeronautical and space sciences,”and cooperation with other nations. NASA wasestablished to “plan, direct and conductaeronautical and space activities. ”25

These general goals and this frameworkhave been reaffirmed subsequently, mostrecently in the “Directive on National SpacePolicy” and the “White House Fact Sheet on

—‘5 ’ ’Nat lona l Aeronaut ics and Space Act o f 1958, as Amended, ”

in Space Law, Selected Basic flocuments, Senate Committee onCommer[ e, Science, and Transportation; U.S. Government Print-ing Of flee, 1978; pp 499-503


U.S. Civil Space Policy,” both issued in 1978. Inthese documents the Carter administrationcommitted the United States to increase scien-tific knowledge, develop useful commercialand Government applications of space tech-nology, and “maintain United States leader-ship in space technology. ” Establishing andmaintaining satisfactory relations between thecivil and military programs was recognized asa priority issue, and the National SecurityCouncil was charged with providing coordina-tion for all Federal agencies involved in space.Cooperation with other nations, including jointprograms and the development of a stablelegal regime allowing all nations to use outer-space for peaceful purposes, were emphasizedas important goals. The investment and directparticipation of the private sector in space ac-tivities was addressed in the context of remote-sensing systems. NASA’s responsibilities forthe operation, as opposed to research, de-velopment, and testing, of applications sys-tems have yet to be clarified.26

The U.S. civil space program can thus besaid to have an ongoing set of policy goals:

●

●

●

●

●

●

scientific — increasing knowledge,political — maintaining U.S. preeminence,andeconomic–developing useful commer-cial applications.

It also has a continuing policy framework:

separation of civil and military programs(with various mechanisms for coordinat-ing different efforts),cooperation with foreign countries andagencies, andseparation of NASA R&D and prototypedevelopment programs from commercialapplications (an unclear relationship).

Would an SPS program alter the basic thrustof U.S. policy? I n terms of goals, an SPS pro-gram would be primarily an applications effortfor commercial purposes, and hence would

26’’ Description of a Presidential Directive on National SpacePolicy, j une 20, 1978, ” and “White House Fact Sheet, U.S. CivilSpace Policy, Oct 11, 1978,” in Space law, pp 558-564.

further the economic goals that have been em-phasized in recent policy proclamations.

The political end of U.S. preeminence inspace, though no longer stressed as strongly asduring the Apollo program, would also beserved by commitment to an SPS. (Thisassumes that the project would be successful;failure of such a high-visibility effort could beextremely damaging to U.S. prestige. Interna-tional cooperation might tend to mitigate thisdanger. )

The SPS program would not be focused onincreasing basic scientific knowledge, butmuch of the research and experimentation re-quired would provide some scientific gains; inaddition, the infrastructure for SPS (e. g., plat-forms, transportation vehicles) could be usedfor a multitude of scientific projects in space.There is some danger, though, that focusingthe national space program on such a majorapplications project as SPS would divert re-sources and attention, at least temporarily,from scientific missions.

The effects of SPS on the U.S. policy frame-work will depend on how it is financed andmanaged. Civil-military relations could bealtered. Although the SPS is not technicallysuited to be used as a weapons system, muchof SPS technology and infrastructure, espe-cialIy the transportation vehicles, would havemilitary uses (see ch. 4). Furthermore, it isunlikely that a project with the scope and im-pact of SPS could be approved by Congresswithout at least the tacit consent of the De-partment of Defense (DOD). In the foreseeablefuture, DOD requirements for aerospace ex-pertise and facilities will be great, and SPS maybe seen as a competitor for scarce resourcesunless direct defense benefits can be realized.Although an SPS program would not be run bythe military, it might be necessary for the civiland miIitary sectors to be more closely coor-dinated than has previously been the case.

Foreign cooperation and joint venturesmight be encouraged not only by the desire toimprove international relations but by moredirect economic considerations. (see ch. 7).These considerations would be strong enough

Ch. 6—SPS in Context • 137

to provide for a greater degree of sharedresponsibility than in any equivalent U.S. pro-gram to date, unless U.S. military involvementproves an insuperable obstacle. Internationalparticipation might be such that the projectcould no longer be run as a U.S. venture withlimited foreign cooperation, but would be-come a truly multinational effort with nodominant U.S. role.

The relation between public and privateparticipants would be a major issue in any SPSprogram. Policy in this area has not been clear-Iy established, though there is precedent fordetaching applications projects, such as satel-lite communications and Landsat, from NASAafter development is completed. NASA hasconducted all U.S. civilian launches on areimbursable basis; it is unclear what wouldhappen if private firms wished to build and/orlaunch their own vehicles, as has been sug-gested for the shuttle. If, as is presently thecase, a Federal SPS program were managed byDOE or some other agency besides NASA,NASA might be responsible for only a limitedpart of SPS development and NASA restric-tions and policies might not apply.

Current and Projected Space Projects

SPS would be strongly affected by currentspace programs and capabilities, and in turnmight also determine what many of those pro-grams would be. However, since an SPS devel-opment decision is unlikely to be made before1990, and may not be possible until 2000, (seech. 4), SPS will not shape NASA projects con-ducted during the next decade (though it mayaffect long-range planning).

Historically, NASA has devoted the majorportion of its resources to a single major proj-ect, first the Apollo lunar-landing program,and then the Space Shuttle. However, there arecurrently no plans for a similar “centerpiece”project to follow the Shuttle; the White HouseFact Sheet asserted explicitly that: “it isneither feasible nor necessary at this time tocommit the United States to a high-challengespace engineering initiative comparable toApollo.” Instead, present plans call for a

number of smaller scale operations and scien-tific missions centered around use of the Shut-tle and other components of the Space Trans-portation System (STS). The lack of a single,clear, overriding project goal for the civilianspace program has been criticized for squan-dering NASA and contractor capabilities, andleaving the United States without a visionaryand profitable use for the new transportationcapabilities under development. This problemwill undoubtedly be addressed during the1980’s, but jurisdictional and philosophicaldifferences, as well as budgetary constraints,may make consensus difficuIt to achieve.

For the next 5 years, NASA plans to concen-trate on a number of areas: those most directlyrelevant to SPS include:

1. Transportation and Orbital Operations:

2

Transportation efforts will concentrate onmeeting shuttle schedules but also in-clude other elements of STS: the inertialupper stage, for placing payloads in geo-synchronous orbit (CEO) (under deve l -opment by the Air Force); Spacelab, formanned and unmanned experimentation(joint program with ESA); development oforbital transfer vehicles such as an elec-tric orbit transfer vehicle (EOTV); systemsto handle payloads outside of the Shuttle;and free-flying platforms. Each of theseprograms will be important for improvingour capability to move and work in space,and hence directly relevant to SPS. Thekey element is the Shuttle, which mustwork and work well if these projects are toproceed during the 1980’s. Delays in Shut-tle operations, or in building additional or-biters, will not only retard these projectsbut also might prevent SPS-specific re-search flights as envisioned in one of thepolicy Options from taking place in thelate 1980’s (see ch. 4).Immediate Appl icat ions: In this area,space processing experiments to be con-ducted on Spacelab could be important indetermining the proper kinds of materialsfor SPS construction, as well as prospectsfor direct processing of raw materials inorbit. Communications and remote-se ns-

83-316 0 - 81 - 10


ing development will involve work withmicrowave transmission, lasers, and mir-ror systems, as well as detailed studies ofthe upper atmosphere,27 which will b evital in determining the environmental ef-fects of launch effIuents and energy trans-mission beams.

3. Solar Radiation:The Solar Maximum Mis-

4

sion (launched February 1980) and the up-coming International Solar Polar Mission,scheduled for 1983, will study solar radia-tion and its effects on the near-Earthspace environment. Such informationcould be important in designing SPS solarcells and in adding to our knowledge ofthe effects of radiation on SPS workers:ionizing radiation in CEO is a potentiallyserious obstacle to human effectivenessand could be decisive in determining theoptimal “mix” between automated andhuman-controlled operations.Humans in Space: The studies of Shuttlecrew performance as well as specificSpacelab experiments will provide a basisfor determining the long-term effects ofweightlessness and cramped quarters, andfor designing appropriate equipment toimprove manned performance. 28

The above projects are already underwayand are those for which funding or explicitplanning are in place. NASA has also outlinedother, longer term plans that would be impor-tant to SPS. NASA’s Office of Space Transpor-tation Systems’ long-term goals are predicatedon the assumption that “the growth of U.S.civilian space programs in the 1990’s will prob-ably continue to be moderate and evolu-tionary, rather than rapid or ‘Apollo-like,’ “and that “space projects will increasingly haveto demonstrate significant economic return orperform essential services to obtain approval.”The specific goals are: 1 ) routine operation ofthe STS by the mid-1 980’s; 2) routine operationof unmanned large low-Earth orbit (LEO) plat-forms by the mid-1980’s; 3) a permanentmanned facility in LEO for research, construc-

Z7N~t10nal Aeronautics and space Adm Inistration, ~AsA f’ro-gram P/an, F;sca/ Years 1987 Through 7985, 1980, p 1 0 7

*a Ibid, pp 3-5

tion, and operations, by the end of the 1980’s;and 4) a permanent facility in GEO, eventuallymanned, by the late 1990’s. Meeting goalswouId involve:

•

●

●

●

augmenting the Shuttle’s thrust, perhapsvia a Iiquid booster;developing EOTVs, such as the low-thrustion-propelled Solar Electric PropulsionSystem (SEPS) for service to geosynchro-nous orbit;equipping the Shuttle and its moduleswith a 25-kW add-on electrical power sys-tem; andcarrying-on a ground and space-based ef-fort to fabricate and assemble precisionstructures in orbit .29

All of these projects could have direct bear-ing on SPS and on any future decision to pro-ceed with SPS development. Some of thelonger term aims, such as SEPs, might overlapwith an SPS development program, that wouldprovide a strong impetus for their completion.

NASA is not the only body with plans forspace. DOD goals, though largely classified,include large platforms, orbital microwaveradars, and space-based lasers. DOD require-ments couId drive NASA projects such as Shut-tle thrust augmentation, or lead to separatedevelopment of SPS-useful equipment.

Other long-range projects have been sug-gested by many individuals and organizations,in and out of government. In the transporta-tion area, these include very large fullyreuseable launchers; laser-propulsion; 30 Iight-sails, to power low-acceleration transfervehicles or deep-space missions; 31 and mass-drivers to lift material off the lunar surface, oras a solar-powered propulsion system forspace vehicles.32 Other than the building offull-scale permanent colonies, SPS is thelargest space project proposed to date, in

2’1 b[d Pp 1 9 0 - 2 0 5‘ ( lA Her tz berg , K Sun, W Jones , “Laser A i r c ra f t , A s t r o n a u t i c s

and Aeronautics, March 1979 p 41“K Eric Drexler, “Spinoffs To and From SPS Technology: A

Preliminary Assessment,” OTA Working Paper, June 1980, p. 9‘2(, O’NeIll, G Driggers, B. 0’Leary, “New Routes to Man-

ufacturing In Space, ” A s t r o n a u t i c s a n d A e r o n a u t i c s , O c t o b e r

1980 Pp 4 6 5 1


terms of expense, returns, timeframe, andamount of people and materials placed in or-bit; if developed it would be a spur to all formsof cheaper space transportation.

SPS’s effect on space projects would dependto some extent on the type of SPS that wouldbe developed, the size of each unit, and thesize of the entire system (as well as the scopeand type of space program in place at thetime). A geosynchronous microwave SPS simi-lar to the reference design would require ex-tensive transfer vehicle capacity and hencelead to accelerated development of EOTVs,chemical-powered personnel vehicles, andmanned GEO construction stations. A laser-SPS in LEO, on the other hand, would requirerelatively little LEO to GEO transfer capacity.A mirror-system might need even less up-graded Iift or construction capacity in order tobe fully deployed (see ch. 5).

A large SPS system consisting of many satel-lites would tend to have greater economies ofscale, leading to the development of more anddifferent sorts of vehicles, and greater mass-production and automation. In-orbit process-ing of lunar or asteroidal raw materials wouldalso be feasible only if a very large systemwere built, to justify the front-end costs oflunar mining and orbital processors.

Institutional Structures

Would an SPS program require a change incurrent national institutions? The completedSPS Concept Development and EvaluationProgram33 was a joint DOE/NASA effort, withDOE providing most of the management andNASA providing technical support. A decisionto have further SPS research, development,and demonstration efforts managed by DOEwould likely prove awkward, since the bulk ofthe up-front development costs would be forspace systems; hence DOE would have to passmost of its SPS funding to NASA, or attempt todevelop its own contractor relations and in-house space capability, which would be time-

“Satellite Power Systems Concept Development and Evalua-tion Program, “Program Assessment Report Statement of Find-ings,” November 1980, DO E/E R-0085

consuming and wasteful. SPS would require amuch clearer and stronger coordinating mech-anism than currently exists for national spaceprograms, since not only NASA and DOE but anumber of other departments and agencieswould be involved. 34

Extensive NASA involvement in SPS wouldrequire clarification of NASA’s appropriaterole in commercial applications ventures, andperhaps modification of NASA’s charter. Bothunderlying policy— i.e., to what extent NASAshouId operate applications systems, such asLandsat and communication satellites—andspecific procedures for turning over patents,technology, and hardware to private industryor other Government agencies, have been sub-ject to continuing controversy. *

It is probable that a separate public orquasi-governmental body would eventually beset up, outside of NASA and DOE, to managean SPS program. Such a decision would be in-fluenced by, among other things, the desiredmix of public and private funding, and thedegree of international involvement. Possibleforms such a body might take are discussed inchapter 9, Financing Ownership and Control,and in chapter 7.

Indirect Effects and “Spinoffs”

There would be three kinds of indirect ef-fects of SPS development:

●

●

●

technology and hardware developed forSPS that could have other uses (and thatotherwise would not be developed orwouId be developed at a much slowerpace),uses of the SPS itself other than providingterrestrial baseload electric power (andthat would otherwise not be provided for),andeconomic/technological changes and ba-sic shifts of national attitudes

SPS developed technologies and hardware:Most, though not all, of these spinoffs wouldrelate to space capabilities. We have already

‘[J( )1 re[)ort o n \ PS .1 nd G o v e r n m e n t dgenc Ief — In press

*See OTA assessment, Space Policy and Applications, i n

p r e p a r a t i o n


seen that NASA’s transportation plans includemany elements directly useful to SPS, whichSPS development would tend to accelerate ormodify. Although the reference system callsfor heavy-lift launch vehicles able to carry 400tons to LEO, and a 5,000-ton payload EOTV,the exact types of vehicles needed cannot yetbe specified. The proper mix between size,numbers, and types of vehicles depends onmany unknown factors, including the type ofsystem, its location, and the number of satel-lites to be built.

The combination of improved and cheapertransportation, robotics and teleoperation,possible new construction materials (such asgraphite composites), and human expertise,would make possible many commercial spaceactivities. Large communications platforms,scientific and industrial research facilities,processing plants for chemical and raw mate-rials —these are a few possibilities. Past ex-perience teaches that commercial exploitationfollows in the wake of the development of newcapabilities, and cannot be accurately fore-seen. 35

Space industrialization could be greatlyenhanced by the use of extraterrestrial rawmaterials. SPS could lead to lunar or asteroidalmining by fostering the development of trans-port and robotics capacity, as well as by pro-viding a major market for processed productssuch as aluminum, steel, silicon, and oxygen.The most detailed studies have examined min-ing the lunar surface, and launching rawmaterials to orbiting processors via an elec-trically powered mass driver. Others have sug-gested mining or capturing a small asteroid,preferably a carbonaceous-chondrite asteroidrich in carbon and high-grade iron/nickel ore.36

Establishing such facilities, which might bedone in the later stages of SPS development,could considerably reduce the costs oftransporting material to high orbits.

On the ground, SPS would require large-scale automated production of solar cells;

‘5 Woodcock, op cit , p 123’Drexler, op. cit , pp 10-11

some of this technology could also be used forground-based solar projects.

Space or ground-based industries using SPS-developed technology or hardware could, atleast temporarily, compete with SPS for scarceresources. A mechanism for allocating prior-ities might have to be established to resolvecompeting claims.

Alternative SPS uses; Depending on the elec-tromagnetic environment (i.e., on the type ofsystem used and the amount and type ofshielding available), the SPS platform, whetherin (GEO or LEO, could be used as a station for avariety of communication and remote-sensingequipment. A GEO SPS wouId be especiallyuseful, due to the relatively small number ofpositions available. Remotely operated opticalastronomy devices could be placed near or onSPS as a way of escaping the interferencefaced by Earth-based telescopes. Given a largeamount of space traffic associated with in-creasing industrial and military space flights,the SPS station could become a focal point forlocal storage, refueling, and rest and relaxationfor crews – a kind of spaceport. Living quartersfor maintenance crews and constructionworkers could be expanded and upgraded intooccasional (and, initially, very high-cost)tourist accommodations.

SPS electricity could be used in orbit, eitherat the satellite itself or at remote sitesequipped with receiving antennas, to providepower for industrial activities. Processing,especially of extraterrestrial raw materials,could require large amounts of electricalpower that might be more efficiently suppliedby a central SPS than by building specific elec-trical capacity.

Some SPS designs, especially the mirror-systems, might produce enough power to beused for local climactic modification. Thiswould require more precise understanding ofweather systems than is now available. Orbitalmirrors have also been suggested as a way ofproviding nighttime illumination of citiesand/or of cropland to enhance growth. 37

‘“Woodcock, op cit

Ch. 6—SPS in Context . 141

Special mirror surfaces that reflect onlyspecific wavelengths would need to be de-veloped for such purposes.

Generic economic and social effects: A suc-cessful SPS could be instrumental in provokingan economic upsurge by stimulating new pro-duction in the aerospace and energy indus-tries, and new industries altogether in spacefabrication, solar cells, antenna construction,and so on. Specific technical advances neces-sary for SPS and Iikely to provide economicspinoffs have been mentioned. The likelihoodof a revolutionary new product, comparable ineffect to the transistor or microchip, resultingfrom SPS is unpredictable. Estimates of the ag-gregate economic and technical effects oflarge research and engineering projects, suchas Apollo or nuclear reactors, vary enormous-ly. Some credit a large portion of the U.S.economic vitality and technical leadership inthe 1960’s, especially increases in research,engineering, and project management skilIs, toFederal investments in the Space program .38

‘8 Drexler, op clt , pp 8-9

SPS might prove equally stimulating. Othersargue that these resources would have beenavailable anyway, and could have been used inmore efficient ways.

Arguments about long-term social vitalityaIso often revolve around the Apollo ex-perience. The optimism and vision thatc h a r a c t e r i z e d t h e “ A p o l l o d e c a d e ” a r e c o n -

t r a s t e d w i t h t h e p e s s i m i s m , u n c e r t a i n t y , a n d

sense of l imi ts o f the post -Apol lo 1970’s . Skep-

tics, however, argue that Apollo represented amisguided effort to escape from more pressingsocial and political problems, and that thespace program lost public support when thisbecame apparent39 (see ch. 9). Whether theUnited States will regain some of its former en-thusiasm for large high-technology projectswiII depend partly on the success of current ef-forts, such as the Space Shuttle, and on themagnitude and type of benefits that such proj-ects offer.

“Klaus Helss, “New Economic Structures for Space In theI Ightlei, Astronautics ancf Aeronautics, January 1981, p 17

CHAPTER 7

THE INTERNATIONAL IMPLICATIONSOF SOLAR POWER SATELLITES

ContentsPage Page

Introduction . . . . . . . . . . . . . . . . ......145

Degree and Kind of Global Interest in SPS .146E c o n o m i c I n t e r e s t . . . . . . . . . . . . . . . . . . 1 4 6N o n e c o n o m i c I n t e r e s t . . . . . . . . . . . . . . 1 5 3

Legal Issues. . . . . . . . . . . . . . . . . . . . . . ...154Status of the Geosynchronous Orbit. . . .155Environmental Considerations . . . . . . . .156Military and Arms Control Issues . .. ...156Common Heritage and the Moon Treaty. 158

Advantages and Disadvantages ofM u l t i n a t i o n a l S P S . . . . . . . . . . . . . . . . 1 5 9

Unilateral Interests. . . . . . . . . ........160Multilateral Interests . . . . . . . ........162P o s s i b l e M o d e l s . . . . . . . . . . . . . . . . . . . 1 6 3

National Security implications of SolarP o w e r S a t e l l i t e s . . . . . . . . . . . . . . . . . . 1 6 7

Vulnerability and Defensibility. . ......168Current Military Programs in Space .. ..170

Use of SPS Launchers and ConstructionFacilities . . . . . . . . . . . . . . . . . . . . . .171

Mi l i t a ry Uses o f SPS . . . . . . . . . . . . . . . . 172ownership and Control . . . . . . . . . . . . . .173

Foreign Interest. . . . . . . . . . . . . . . . . . . . . .174E u r o p e . . . . . . . . . . . . . . . . . . . . . . . . . 1 7 4Soviet Union . . . . . . . . . . . . . . . . . . . . . .174Japan . . . . . . . . 175Third World . . . . . . . . . . . . . . . . . . . . .175

S t u d y R e c o m m e n d a t i o n s . . . . . . . . . . . . . 1 7 5

LIST OF TABLES

Table No. Page

24. Primary Energy Demand. . ..............14625. End-Use Electricity Demand . ...........14726. Amount of Global Installed Capacity ., .. ..14727. SPS Market in 2020/2025. . ..............151

Chapter 7

THE INTERNATIONAL IMPLICATIONSOF SOLAR POWER SATELLITES

INTRODUCTION

The development of solar power satellites(SPS) requires consideration from the perspec-tive of its international implications. First, as aspace technology SPS would operate in aglobal medium, outside of any national terri-tory, which is subject to international law em-bodied in existing treaties and agreements.Secondly, as a major energy project the SPSwould affect supply and demand for what is byfar the largest commodity traded on interna-tional markets, one that is of vital interest toall countries. Thirdly, because of its tremen-dous cost and technical sophistication an SPSsystem could have a strong effect on the econ-omies of states involved in its construction.And finally, development of an SPS and of thelaunchers needed to build and maintain it maygive its builders significant military and/oreconomic leverage over other states.

This chapter will look at the SPS primarilyfrom a political perspective, because in thefinal analysis SPS development will depend onnational efforts, instigated by national leaders,paid for– in large part– by public funds. TheUnited States is the only country in whichthere is any likelihood that there would besignificant private-sector responsibility for SPSdecisions. The importance of national effortswould be especially crucial in the near futurewhen SPS projects are in the R&D and proto-type construction phases.

Actors. – If SPS is developed, Governmentinvolvement would be guaranteed becauseSPS would affect vital national interests in anumber of areas, e.g., external security, pres-tige and influence, and economic growth.Energy policy in itself has become a centralcomponent of national planning in most coun-tries.

Nonstate actors would be involved as well.On the international level these include global

organizations such as the United Nations andits specialized agencies; multilateral groupssuch as the Organization for Economic Coop-eration and Development (OECD) and OPEC;and regional groupings such as the CommonMarket and the European Space Agency (ESA).On the substate level there are numerous in-terests, including those of private companies,public utilities, and governmental agencies,that often conflict and that seek to influencenational decisions. Furthermore, the role of thelarge multinational corporations in interna-tional relations is in some areas very great andoften independent of direct government con-trol

However, for the SPS, national decisions andinterests are likely to predominate. Althoughthe rise of energy as a major global concernhas led to the formation of numerous interna-tional organizations (such as the InternationalEnergy Agency) and to intense discussion ofthe global dimensions of energy prices andshortages, the overall impact has been to placedecisions about energy consumption and pro-duction more and more firmly in the hands ofnational governments. In general, it seems thatthe role of the state in furthering peace andsecurity, stability, prestige, and economic well-being has not been supplanted by other enti-ties.

Forecasting. – B e c a u s e S P S i s a p r o j e c twhich, if pursued, will not reach fruition for atleast 20 years, assumptions must be madeabout future political and economic develop-ments. Since radical changes are by definitionunpredictable, these will be unavoidably con-servative. In general, it is assumed that thebasic political and socioeconomic alinementsof today’s world are likely to continue. In thepast, fundamental realinements of the interna-tional political structure have often been the

145


result of major wars or of deep-seated altera- creasing skepticism in American and Europeantions in political and social expectations, att i tudes towards the space program andneither of which can be confidently predicted. nuclear energy in the Iate 1960’s and earlyEven relatively small shifts in public support 1970’s, for instance, has decisively affectedfor various programs can have large effects; in- our current space and energy capabilities.

DEGREE AND KIND OF GLOBAL INTEREST IN SPS

National and regional interest in the SPS willstem from an evaluation of the ways an SPSsystem would affect all the components of na-tional interest outlined above. The degree andkind of interest shown will vary from nation tonation. In deciding what institutional structureto use for SPS development, it is crucial totake these various foreign interests into ac-count. In this case, interest can be divided —somewhat arbitrarily— into economic and non-economic components. The economic interestin SPS would be focused on SPS’s ability toprovide electricity, and hence on the local de-mand for electricity over the time SPS be-comes available. Noneconomic concernswould include prestige and national securityinterests.

Economic Interest

A recently completed study by the interna-tional Institute for Applied Systems Analysis(IIASA), Energy in a Finite World,1 provides themost up-to-date project ions of long-rangefuture global energy demand. The IIASA studyuses a global model with several differentscenarios, broken down on a regional basis.We will present the high and low estimates togive the entire range of predictions; it shouldbe noted that the lower estimates are closer tothose of some recent U.S. studies, such asEnergy in Transition 1985-2010, by the NationalAcademy of Sciences.2 (See app. C.) In generalthe slowdown in gross national product (GNP)growth over the past several years, and thesharp rises in oil prices in 1979, have caused

‘Energy in a Finite Worid, A Global Systems Analysis, EnergySystems Program Group, International Institute for Applied Sys-tems Analysis (Cambridge, Mass.: Ballinger Publishing Co,, 1981).

‘Energy in Transition 1985-2070 (Washington, D. C.: NationalAcademy of Sciences, 1979).

recent energy forecasts to be much lower thanthose of only a few years ago. Since OTAbelieves that IIASA’s analysis may tend tooverestimate future energy demands (see app.C), especially in the advanced industrializedcountries, the following figures should be usedwith some caution.

The IIASA projections for primary energydemand are based on an integrated model inwhich supply and demand are matched on aglobal basis (see table 24). (See app. C.)

Historically, the rate of growth in electricaldemand has been approximately twice as highas that of total energy demand. IIASA predictsthat it will remain higher, but by a factor of 1.4instead of 2.0.3

Currently, electricity a c c o u n t s f o r a naverage of 11 percent of global end-useenergy, ranging from 6.5 percent in developingcountries to 12 percent in the OECD. By 2030,IIASA expects this figure to rise to 17 percent(in both high and low scenarios), with develop-ing countries using 13 percent and OECD 21percent, reflecting an annual increase in usageof 2.6 percent (low) to 3.4 percent (high).4

‘Finite World, op. c it , p. 482.‘Ibid

Table 24.—Primary Energy Demand (Quads)—

1975 2000 2030— Low High Low High

OECD. . . . . . . . . . . . . . . .146.8 200.3 224.5 266.3 393.4SU/EE (Soviet Union,

E. Europe) . . . . . . . . . . 55.0 98.9 110.3 149.4 219.1Developing . . . . . . . . . . . 37.7 107.0 148.9253.8 453.1Global Total. . . . . . . . . . .239.5406 .2503.7669.5 1,065.6S6URCE: Energy in a Finite World; conversion to Quads done by the Office of

Technology Assessment.

Ch. 7—The International Implications of Solar Power Satellites ● 147

Electricity use is affected by many factors,including changes in end-uses, (such as heatpumps or electric cars), saturation of demand,and the cost and availability of fuel (see ch. 6).Table 25 shows the IIASA figures for end-useelectricity demand.

Assuming 70-percent load factors and 15-percent losses in transmission and distribution,IIASA estimates for installed generating ca-pacity in 2030 are shown in table 26.

Although the IIASA report is pessimisticabout the possibility of extensive use of alter-nat ive energy sources, such as fusion orground-based solar, by 2030, it points out thata breakthrough in fusion or solar-cells wouldchange the supply and cost of electricity dras-tically. Cheap photovoltaics might encouragea shift towards a “hydrogen economy, ’’withelectricity produced in high-insolation desertareas being “stored” and transported as hydro-gen. 5

Barring such developments, future baseloadelectrical demand will be met overwhelminglyby coal and nuclear sources (see app. C). IIASAalso predicts that coal will be used extensivelyfor producing liquid fuels, especially in coal-rich regions such as North America and the

‘I bid., p. 163.

Table 25.–End-Use Electricity Demand (Qe)

1975 2030— Low High

OECD . . . . . . . . . . . . . 12.5 35.3 50.2SU/EE . . . . . . . . . . . . . 3.9 15.5 25.4Developing. . . . . . . . . 1.8 23.3 41.3Global Total . . . . . . . . 18.2 74.1 116.9

SOURCE: .Errergy in a Finite Wor/d, p. 659. These numbers should be taken asapproximations, since they are based on IIASA estimates of the per.cent of end-use demand that will be met by electricity. For graphicpresentation, see Energy, p. 481.

Table 26.—Amount of GlobalInstalled Capacity (GWe)

1975 2000 2030Low High Low High

1,600 3,550 4,390 6,320 9,845

SOURCE: Energy in a Finite World, p. 483.

Soviet Union — up to 55 percent of coal pro-duction in North America by 20306 (see app. C).

Regional Variations

In order to understand how different coun-tries might view SPS, it is crucial to highlightthe major regional differences that will affectdemand for electricity. Foremost among themis the question of regional or national self-sufficiency.

SELF-SUFFICIENT AREAS

In the 50-year time-frame considered, it ap-pears possible for three major consumingregions — North America, Soviet Union/EasternEurope, and China –to achieve energy self-sufficiency. This would require rapid develop-ment of indigenous sources of North Americanoil shale, tar sands, and Western coal; for theSoviet Union, untapped oil, gas and coal re-serves in Central and Eastern Siberia; forChina, development of oil and coal depositsand expanded exploration in Western China. Inall three cases very substantial growth innuclear and/or solar, hydro, and other gen-erating sources would also be required. Withthe possible exception of U.S. and Soviet coal,none of these regions is likely to export sig-nificant energy supplies, since indigenousgrowth will absorb most new capacity evenunder optimistic scenarios.

The costs of achieving regional self-suf-ficiency would be very high. Development ofNorth American oil shale and tar sands, for in-stance, on a scale sufficient to produce oil andgas in quantities comparable to the large com-mercial oilfields of today, will cost hundredsof billions of dollars. Such development willalso be “dirty” environmentalIy, involving ex-tensive surface-mining, and hence expensive toclean up and to regulate.

In the Soviet Union, currently the world’slargest oil producer, finding the capital for ma-jor energy investments during the 1980’s willbe difficult. Inefficiencies in central planningpractices are likely to be magnified as de-

“1 bid , p 669,


mands for consumer goods and services in-crease.

China’s energy production potential is notwell enough known to predict future supplieswith any certainty. Oil, coal, and oil shale areknown to be present in large quantities. Cur-rent modernizat ion plans cal l for sizableenergy investments.

ENERGY-DEPENDENT AREAS

Regions without sufficient local resourceswill include Western Europe, Japan, and largeportions of the (currently) developing world.Western Europe and Japan can be expected toinvest heavily in nuclear plants, especially fastbreeders.

Unfortunately neither Western Europe norJapan is in a good position to exploit alternatenonnuclear technologies to alleviate depend-ence on imported oil. Except for a relativelysmall part of Southern Europe, average annualinsolation is low—only 1,000 kWh/m2 in Cen-tral Europe, compared to 2 ,500 kWh/m2 i nArizona. ’ Hydroelectric resources are limitedand already extensively developed. There areno large wooded areas to provide biomass, andregional cropland in densely populated regionsis scarce.

It is likely that Western Europe and Japanwill try to develop assured foreign sources forfuture needs. This may take the form of jointdevelopment of capital-intensive North Ameri-can energy projects, gaining through partialownership an assured source of supplies.Foreign interest in U.S. coal, including invest-ment in mines and shipping facilities, has ac-celerated since the 1979 rise in oil prices. 8

However, it is unlikely that national policy inthe United States and Canada wi l l permitextensive ownership of energy resources byforeign countries or enterprises, or significantexports of nonrenewable fuels, even to friendlycountries. Though the size of the capital re-quirements may allow for foreign participa-tion, it will not be enough to alleviate Euro-

‘K. K. Reinhartz, “An Overview of European SPS Activities, ”Firta/ Proceedings of SPS Program Review, Department of Energy,April 1980, p. 79.

8See “The Coal Ships,” Washington Post, Oct. 13,1980, p, 1.

pean or Japanese shortages. Investment in orlegal control of foreign assets provides little in-surance against price rises or expropriation,when the local government is so inclined.

The underdeveloped energy-poor regionsvary greatly in their levels of development andtheir degree of energy dependence. In virtuallyall cases oil-price rises have seriously ham-pered economic growth. 9 In some instancesthe increases have spurred development of in-digenous sources– nuclear plants in Brazil,Argentina, a n d I n d i a ; b i o m a s s i n B r a z i l ;numerous small-scale hydro and solar projectssuited for decentralized generation. It is in theless developed countries (LDCs) that the great-est proportional surge in energy demand andelectrical usage will come over the next 50years, rising from 12 percent’” to 31 to 35 per-cent of global electrical demand (see app. C).Decentralized systems can be effective inregions without developed utility grids andwhere demand is for small units for domestic,agricultural, and light industrial use. But thebaseload power needed for extensive growthand modernization will be expensive and inshort supply.

ENERGY-EXPORTING AREAS

Current energy-exporters include OPECmembers as well as a few non-OPEC oil pro-ducers, such as Mexico, Malaysia, and theSoviet Union. Over the next 50 years, manycurrent oil-surplus states will cease to export,due to increased domestic consumption and/ordecreased output. The time and rate at whichcurrent oil production in exporting countrieswill diminish depends on the rate of consump-t ion as wel l as future discoveries. I IASApredicts only small increases in exportingcountry production through 2030, with de-mand increases being met primarily by coalliquefaction and unconventional oi ls . Thereport emphasizes that: “The ‘energy prob-lem,’ viewed with a sufficiently long-term andglobal perspective, is not an energy problem,strictly speaking, it is an oil problem, or, more

—‘See Energy in the Developing Countries, World Bank, August’

1980, pp 3-6‘“I bid , p 44.


precisely, a liquid fuels problem.’’ 11 As de-mand grows over the next 50 years, the abilityof countries to import such fuels to make upfor local shortfalls will dwindle, and prices willrise sharply.

In summary then, the 50-year forecast is foran increase in demand for energy of somethree to four times, and an increase in demandfor electricity of some four to six times withrates being somewhat higher in the currentlydeveloping regions. These forecasts are basedon a declining rate of growth in GNP, averag-ing some 2.7 percent (in the low scenario) to 3.7percent (high scenario) per year. (Compared toa global average of 5 percent from 1960 to1975.) In general, energy scarcity will causehigher prices, reducing demand and increasingsupply. The question is whether future supplieswill be so high cost as to force a radical changein Iiving standards and growth rates. Maintain-ing a moderate rate of growth in the developedcountries and a somewhat higher growth ratein the developing world —to provide for popu-lation increases as well as the prospect of realincreases in living standards —will place de-mands on energy resources that guarantee thatenergy costs will consume a larger proportionof national income than in the past. IIASApredicts an increase of 2.4 to 3.0 times in theproportion of gross domestic product (GDP)spent on energy. Even if IIASA’s projectionsprove to be on the high side, future energysources can expect to be competitive within avery high-cost ceiIing.

SPS Contribution

SPS could begin to provide electricity by2010-20 and could be a substantial source ofnew power within the selected 50-year period.None of the global projections to date has con-sidered the possible impact of an SPS systemon future energy scenarios. The rise in elec-trical consumption is expected to be met bylarge increases in coal-fired generators andnuclear plants. However, there are seriousproblems with both methods.

Coal, like oil, is abundant only in certainareas. Unlike oil, it is expensive to ship com-

I I Fjnjte wor/d, Op. cit., P 653

pared to the cost of mining (because of itsbulk), especially overseas and in areas withoutextensive rail Iinks, While oil and gas aresuitable for small-scale household use, coal isexpensive to store, and prohibitively dirty touse (especially in urban areas). And increasedburning of coal could have disastrous environ-mental consequences, including acid rain andglobal temperature increases (see ch. 6). IIASApredicts a 10 to 1.50 C average increase,through 2030, depending on high or low growthrates,

Nuclear plants are characterized by widelypublicized environmental dangers. Even ifthese can be resolved, public opposition tonuclear power, as well as the rapidly increasingcosts of building new nuclear capacity, havealready delayed the production of nucleargenerators, especially in the United States(where al ternat ive fuels are more readi lyavailable than in many other countries). Fur-thermore, the spread of nuclear technology,especially breeders, into more and more partsof the world will almost inevitably make iteasier for more states to manufacture nuclearweapons. Since uranium is concentrated inscarce deposits, largely in North America, theSoviet Union, and parts of Africa, many areaswill be inclined to depend increasingly onbreeders. The safeguards and restrictions setup by the United States to prevent prolifera-tion have been only partially successful whenthe main reason for building reactors has beenprestige-they will be even less effective asenergy needs make nuclear plants essential.

For these reasons, SPS may be attractive asan alternative to other methods of generatingelectricity. In addition, unpredictable factorssuch as a major nuclear accident or the failureof alternative energy sources could spur inter-est in the SPS. SPS would by no means replacecoal or nuclear power within the next 50 years,but could reduce otherwise excessive relianceon these technologies.

Economic acceptance of an SPS systemwould depend on several factors. Overall costsof delivered power will be crucial; these mustbe competitive with other systems. Perhapsequally important would be the division of


these costs between developers, owners, andusers and the way these are shared betweenparticipating countries. Development of anSPS system would require large amounts ofcapital and a high level of technical/engineer-ing expertise. There are three distinct areaswith capital and expertise: 1 ) North America; 2)the rest of the OECD countries (i.e., WesternEurope and Japan); 3) the Soviet Union andEastern Europe. Assuming that extensive co-operation between the Soviet Union and othercountries is unlikely (see p. 161), the two possi-ble collaborators have somewhat different in-terests. North America has the requisite tech-nical/industrial capacity in space transporta-t ion and related areas, but is potent ial lyenergy rich, while Europe and Japan have in-creasing expertise in aerospace and face con-tinued large energy shortfalls. If the future in-terest of these possible participants were es-timated, North American interest would rate aspotentially moderate to high and West Euro-pean and Japanese (along with some other in-d u s t r i a l i z e d a r e a s – S o u t h K o r e a , T a i w a n ,South Africa, Australia) as potentially veryhigh. In North America, capital and interest inSPS would be competing with coal and synfueldevelopment, as well as nuclear energy; in therest of OECD, primarily with nuclear develop-ment. In general, development of technologiesusing renewable or inexhaustible fuel sources,(such as SPS, but also fusion, ground-basedsolar, and biomass) would be preferred todepletable ones.

The possible cooperative mechanisms forSPS development and operation will be dis-cussed later (see Advantages and Disad-vantages of Multinational SPS, pp. 159-163). It isimportant here to see that potential SPS userswith limited initial capital and expertise tocontribute to an SPS system might need spe-cial incentives to participate in buying SPSpower. A major economic consideration forsuch SPS users might be the lack of direct andindirect spinoffs from SPS part ic ipat ion.Ground-based antenna construction would re-quire large amounts of unskilled labor, butwould provide few technical or managerialposts. The capability to participate directly in

building and deploying the satellite portion ofthe system is probably beyond the reach ofmost of the present LDCs over the next 50years, so that relying on SPS power might beseen as undercutting efforts to develop an in-digenous energy infrastructure. Payments toforeign companies for such power would be adrain on scarce foreign exchange reserves com-pared to development of local resources,which cause ripple effects in the economy.User governments would be sensitive aboutdepending on a foreign high-technology energysource, even if costs and other aspects arefavorable.

What is the potential global market for SPS?To date, only the studies by Maurice Claverieand Alan Dupas have attempted to estimatethis in any detail. Their recent papers12 presenta possible methodology for making SPS projec-tions. Unfortunately, their results are based onenergy demand projections completed in 1976and 1978 that are now considered to have con-siderably overestimated future electricity de-mand’ 13 14 (see app. C).

From these projections Claverie and Dupasestimate the maximum demand for large elec-tric powerplants (LEPP) (see map in app. C),and calculate SPS demand assuming either 10-percent or 50-percent market penetration by 5gigawatt (CW) SPSs (see table 27).

Even allowing for the high estimates of theenergy projections used, the Claverie-Dupascalculations must be considered very roughupper estimates of future demand; in particu-lar, cost comparisons with alternative sourceswere not taken into account. Claverie andDupas attribute much of SPS’s potential at-tractiveness to environmental and politicalfactors rather than strict cost advantages. 15

—‘*M Claverie a n d A . Dupas, “Preliminary Evaluation of

Ground and Space Solar Electricity Market in 2025,” 29th IAFCongress, October 1978; “The Potential Global Market in 2025for Satellite Solar Power Stations, ” May 1979; “PossibleLimitations to SPS Use Due to Distribution of World Populationand World Energy Consumption Centers, ” 31st IAF Congress,September 1980

‘ ‘Edison Electric Institute, Economic Growth in the Future(New York McCraw-Hill, 1976), pp. 215-234

“World Energy Conference, Wor/cf Energy Demand (New York:IPC Science and Technology Press, 1978)

‘5Claverle and Dupas, “Potential Market, ” op cit., p. 4.


Table 27.–SPS Market in 2020/2025 (G We)

10% of New LEPP 50% of New LEPPCWEa WECb CWR WEC

OECD. . . . . . . . 135 75 685 365SU/EE. . . . . . . . 40 260 195Developing . . . 50 85 430 435Global . . . . . . . 275 200 1,375 995

*WR - Case Western Reserve.bWEC. World Energy Conference.

SOURCE: Adapted from Claverie and Dupas, Potential G/oba/ Market, p. 4.

Within the limits of this study the Claverie-Dupas estimates using the IIASA projectionscannot be dupl icated. However, by usingIIASA’S estimates of installed capacity in 2030,a rough estimate of global demand can bemade. We can assume that 20 percent of ca-p a c i t y w i l l b e r e s e r v e , t o g u a r d a g a i n s toutages, and that of the remaining 80 percent,65 percent will be baseload. Moreover, if weaccept Claverie and Dupas’ estimate that 10percent of world demand will be met by decen-tralized sources, then the global estimate ofthe maximum possible demand for installedbaseload capacity in 2030 would be: 80 per-cent (peakload) x 65 percent (baseload) X 90percent = (approximately) 47 percent of totalinstalled capacity.16 Using the IIASA estimates(tabIe 26) of 6,320 (low scenario) to 9,845 (high)GWe, then we get 2,970 to 4,627 GWe as thepotential demand for baseload capacity.

The amount of new capacity supplied bySPS would depend on the percent met by SPSas opposed to alternate generating sources. Ifwe assume 10-percent market penetrat ionthere would be demand for 295 GWe (low) to465 GWe (high); if market penetration were ashigh as 50 percent (which is not probable, atleast by 2030) there would be demand for 1485to 2315 GWe. However, it should be noted thatconventional generators built from 1990-95 onwill still be in operation by 2030; since SPSwould not be available until 2010-15, the newcapacity market will be considerably smallerthan the total demand.

The number of satellites this demand repre-sents would depend on their size; estimates

“See: “SPS-The Implications for the Utility Industry,”working paper for OTA workshop, July 1980, p, 12,

range from 5 GW down to 0.5 GW (see ch. 5).Development of smaller sizes would greatlyimprove the market penetration of SPS by miti-gating two serious obstacles: the large size ofreference rectennas, and the problems ofinserting large blocs of power into utility grids.

Rectenna size in the 5 GW reference designis 10 x 13 km at 350 N., including a 2 km buf-fer zone. Reducing the size of the design to 1.5GW would necessitate a receiving antennaonly 6.5 X 5.5 km, lowering costs and makingsiting more feasible. In European demandcenters, mostly located from 450 to 650 N.,rectennas would need to be much larger.Given Europe’s high population densities,many experts have suggested placing recten-nas offshore in shallow North Sea waters. 17

Similar problems would be faced in the North-eastern United States, Japan, Eastern China,and India. Though apparently feasible, placingrectennas offshore would add considerably totheir cost.

Even more important, a reduction in sizewould enable SPSs to be used by smaller utilitygrids, since utilities in developed countries donot generally make use of single generatingunits supplying more than 15 percent of theutility’s total capacity, because of the need toensure against generator failure (see ch. 8).Conversely SPSs, even in less than 5 GW units,may be a spur to integration of utility grids inorder to make use of the SPS’s large power in-crements. Currently, there is widespread in-tegration of national grids in both Eastern andWestern Europe. Western Europe has an inter-connected high-voltage network, with routinecommercial exchanges of power, which is co-ordinated by organizations such as the “Unionpour la Coordination de la Production et duTransport de l ’Electr ici ty.” 18 In Eastern Eu-rope, Comecon has established an integrated150-GW grid including all of Eastern Europeand the Ukraine.

‘7P Q Collins, “Potential for Reception of SPS MicrowaveEnergy at Off-Shore Rectennas in Western Europe,” Fina/Proceedings, p. 529.

“Arnaldo M, Angelini, “Power for the 80’s: A Challenge forWestern Europe,” Spectrum, September 1980, p. 44.


Successful integration of national grids ispossible only where there is an expectation oflong-term stable relations with neighboringcountries. Unfortunately, though LDCs couldbenefit greatly from regional interconnections,such expectat ions are rare in developingregions where integration may be necessary toaccommodate large blocs of power, and toshare the costs of building expensive recten-nas. Countries and regions with a successfulhistory of cooperation in other areas would bemost likely to join together for SPS integrationas well.

In many developing regions, where the bulkof the population lives in rural areas, thefeasibility of large centralized power plants isreduced by a lack of costly infrastructure,especially transmission l ines and end-usecapabilities. In such an environment decen-tralized generating capacity is preferable toSPSs or other large plants. It has been sug-g e s t e d19 that such countries may be able tomake use of large amounts of electricity forproducing liquid fuels, such as methanol, di-rectly from the basic elements; such fuels canbe easily integrated into economies that cur-rently depend on kerosene or wood for cook-ing and heating. However, using electricity inthis fashion would not be economically feasi-ble. Methanol can be produced from coal at aprojected cost of $0.50 to $1 .00/gal. But at5q/kWhr, the cost just to separate from waterthe amount of hydrogen necessary to make agallon of methanol also lies between $0.50 and$1.00. There would be the further expense ofproviding the necessary carbon (which couldbe provided from carbon dioxide taken fromthe atmosphere). However, producing meth-anol from biomass or from coal (in which thehydrogen, carbon, and oxygen necessary tomanufacture methanol are already present)would be far more cost effect ive. A morereasonable need for SPSs might be for energy-intensive uses such as desalination of sea-water or fertiIizer production. 20 These projectsmight be coordinated on a regional basis.

“J. Peter Vajk, Doomsday Has Been Cancelled, Peace Press,1978,

Z“”D. Criswell, P. Glaser, R. Mayor, et al., The Role of SpaceTechnology in the Developing Countries,” Space So/ar PowerReview, vol. 1,1980, p. 99.

Geographical location may also be an im-portant factor to developing countries. If theSPS were located in geostationary orbit, itwould cost more to beam power to areaslocated far north or south of the equator.Europe, as we have seen, is at a disadvantage;the Soviet Union is in a s imi lar posit ion.Equatorial and tropical states, on the otherhand–most of them LDCs–would be in bet-ter positions to build small-size rectennas.Cheaper power could be an incentive to indus-trial development and foreign investments.

In addition, an equatorial position is optimalfor launching payloads into orbit, since theEarth’s rotational speed at the equator (ap-proximately 1,000 mph) is higher than at otherplaces on the Earth’s surface. Spaceports forsending up SPS construction material mightprofitably be located near the equator, pro-viding benefits for the countries in which theyare placed in the form of rents, infrastructureinvestments, and training of local administra-tors and technicians.

Earlier it was assumed that the Soviet Union,barring some radical change in its political andsocial institutions, would not participate in acooperative SPS venture, except with its EastEuropean allies. As a major space power, theSoviet Union has the ability to go it alone,though without a global market for its productthe costs would be considerable. The SovietUnion has a number of economic reasons toconsider an SPS system, including its increas-ingly remote and expensive convent ionalenergy resources, and the large investment ithas put into its space program (currently esti-mated at some 1.5 to 2 percent of GNP, com-pared to 0.3 percent in the United States21) .The large distances involved in providing elec-tricity to many areas within the Soviet Unionare an incentive to develop a system in whichpower can be sent directly to the area beingserved, without transmission lines and withouttransporting fuel long distances, The SovietUnion has a penchant for big projects, espe-cially when competing with the West. How-ever, currently there is no firm indication that

“Walter A McDougall, “The Scramble for Space,” Wi/sonQuarter/y, fall 1980, p. 81.

Ch. 7—The lnternational Implications of Solar Power Satellites ● 153

the Soviet Union intends to proceed with anSPS.

Noneconomic Interest

Any SPS system would have numerous non-economic aspects relating to national prestigeand security, and different national and re-gional interests can be expected to conflict.There are three separate “arenas” in whichsuch confIicts might arise.

Within OECD

Although cooperation between the UnitedStates and other OECD allies is probable, therewould likely be a high degree of competitioncentered around economic interests. Controlof any joint program, the division of respon-sibilities between countries, and the apportion-ment of economic benefits to be gained fromcontracts let during R&D and construction, areall potential problem areas. In the case of SPS,the industries involved —aerospace and ener-gy—are high-prestige ones in which manycountries wish to develop independent capa-bilities. Fear of economic and technologicaldominance by the United States, or of U.S.failure to follow through on program commit-ments, may be a spur to accelerated develop-ment of European or Japanese launch vehiclesand construction facilities. The ESA’s Arianeexpendable launcher program has been largelymotivated by worries about such dependence,especially by France, Ariane’s prime mover.Japan has announced plans for a new genera-tion of launchers, and non-OECD countriessuch as Brazil and India have built soundingrockets and satellites. Increased competitionwith the United States can be expected overthe period of SPS development.22

East-West

Development of an SPS by the Soviet Unionwould have major international consequences.Since Sputnik, each side has reacted to the ac-tions and statements of the other. Althoughspace successes may no longer be seen asproof of the superiority of one social system to

another, as Khrushchev used to claim, they arestill a vehicle for peaceful competition, and away of impressing allies and potential allieswith individual achievements. Because of itsscope and visibility, the SPS would be a majorsymbol of successful efforts in advanced tech-nology. “Visibility” here is meant literally:23 acompleted SPS, even in geosynchronous orbit,would be easily visible to the naked eye. Theimpact of such an effort would be direct andgreat. It is unlikely that the Soviets could allowa U.S. or Western SPS to go unchallenged. Ifthey felt they could not compete successfully,they would be likely to try to block construc-tion by emphasizing environmental dangers orsupporting Third World demands for sharedcontrol over orbital positions. On the otherhand, a Soviet SPS effort would encourageU.S. projects by acting as a spur to publicopinion and raising fears of Soviet ascendancy.

North-South

Many Third World states would be antago-nistic to SPS development, insofar as controlof the system rests with industrialized coun-tries, West or East. These states would be con-cerned about increased economic and techni-cal dependence on the “North,” and thelimited opportunities for meaningful participa-tion in an SPS system. The SPS could becharged with diverting funds from develop-ment projects and with increasing the gap be-tween the developed and underdevelopedworlds. Internat ional forums such as theUnited Nations and its specialized agenciescould be used as foci for investigations of anyproposed SPS systems and for discussion oflegal measures to bloc them or to give theLDCs various sorts of leverage.

Many developing countries have investedheavily in industries such as steel and oil re-fining in part because of the prestige value ofsuch large and advanced sectors. Energy pro-duct ion is a prominent example–witnessatomic reactors and hydroelectric projectssuch as Egypt’s Aswan Dam. The SPS could beresented because it is unavailable to LDCs;

*’See” Jerry Grey, Enterprise (New York: William Morrow & Co.,1979), p 225221 bid., pp. 71-82.

83-316 0 - 81 - 11


only the receiving antennas could be built onhome territory with local resources. Converse-ly, large amounts of scarce capital might bespent trying to buy an SPS (if they are for sale)and the lift capacity to service it in an attemptto “keep up” with the advanced countries.

The “South” is by no means monolithic, and,if SPS were built, many states would be poten-tial supporters, some because of the benefitsof less expensive electricity and othersbecause of the prospects for future participa-tion. The most likely supporters of an SPSwould be energy-poor countries with a rapidlydeveloping urban-industrial base, such asBrazil, Argentina, Kenya, Turkey, India, andSouth Korea. Any system that reduces Westernimports of OPEC oil reduces pressure on pricesa n d m e a n s l e s s e x p e n s i v e s u p p l i e s f o rvulnerable LDC importers. It has been arguedthat firm plans for building an SPS would ofthemselves put a “cap” on oil price rises bysending a signal to exporters that Western im-ports will drop in the future. z’

Z4HOuSe committee on science and Technology, SpS Hearings

on Ff. f?. 2335, 96th Cong., March 1979, pp 132-180,

The oil-exporting states are in a special posi-tion. An SPS would by no means eliminate oildemand and may prove beneficial by helpingto reduce pressure on exporters to increaseproduction to satisfy rising export needs.Countries with large populations and relativelysmall reserves, such as Nigeria, Indonesia,China and Malaysia, may view SPS as insur-ance against the upcoming depletion of theiroil supplies and may choose to invest some oftheir current earnings in the hope of long-termgains. On the other hand, exporting countries,especially those with long-term reserve poten-tial such as Saudi Arabia, have no immediateuse for an SPS and may be tempted to sidewith other LDCs —for political and culturalreasons — in attempts to put pressure on theWest for greater LDC control. Soviet supportfor such measures could cause the SPS tobecome a highly polarized issue in which theSoviet bloc and the nonalined states seek con-cessions from the West— a not uncommonphenomenon in recent international affairs.

LEGAL ISSUES

The United States and other space-capablestates are currently bound by a number ofagreements that would affect SPS develop-ment.25 Much of existing international law hasbeen formulated at the United Nations (U. N.)by the Legal Subcommittee of the Commit-tee on the Peaceful Uses of Outer Space(COPUOS). COPUOS has been in existencesince 1959, when it began with 24 members. Itnow has 47, with membership expanding asinternational interest in space matters has in-creased. COPUOS decisions have been madeby consensus rather than by outright voting.26

25 See Stephen Gorove, SPS lrrternatjona/ Agreements,DOE/NASA contract No, EG-77-C-01-4024, October 1978; Carl Q.Christol, SPS International Agreements, DOE/NASA contract NoEG-77-C-01-4024, October 1978.

2’Eilene G a l l o w a y , “ C o n s e n s u s DeCISiOrlrnaklrlg ofUNCOPUOS,” )ourna/ of Space Law, vol. 7, No. 1

The most important and comprehensive ofthe currently applicable agreements, all ofwhich have been ratified by the major spacepowers, is the 1967 Treaty on Principles Gov-erning the Activities of States in the Explorationand Use of Outer Space, Including the Moonand other Celestial Bodies . In 1979, COPOUSagreed on a final version of a new treaty, theso-called “Moon Treaty, ” which has so far notbeen signed by the United States or other ma-jor powers. The Moon Treaty applies to theMoon and other celestial bodies, but not toEarth orbit. In addition to COPUOS, importantdecisions on frequency allocations and orbitalpositioning are made by the InternationalTelecommunications Union (ITU), a special-ized U. N. agency.

Ch. 7—The International Implications of Solar Power Satellites . 155

As a new arena of human exploration, legalnorms with respect to outer space have had tobe defined. This has been done through a grad-ual process shaped by actual usage, the exten-sion of existing law, and the explicit adoptionof common principles and regulations.

The outstanding international legal issuesthat might affect SPS development are:

1. the status of the geosynchronous orbit,and the source of jurisdiction over theplacement of satellites;

2. provisions against environmental disturb-ances;

3. the military uses of space and arr-trol implications; and

4. issues relating to the -“facilities and ber ‘“tion of thekind” p“

‘Y u . . .dl

..~ct ~eiimitation be-i Ider the jurisdiction of the

, y ing u n d e r n e a t h t h e a r e a c o n -d-and outer space has never been de-

,led. In recent years a number of stateslocated on the Equator have claimed jurisdic-tion over the geosynchronous orbit on thegrounds that it is not part of “outer space” butis determined by the Earth’s gravitation, and isa limited natural resource requiring nationalcontrol. In December 1976 eight equatorialcountries issued the Bogota Declaration assert-ing their position and laying claim to theorbital segments lying over their respective ter-ritories.

The equatorial states’ claims have been re-jected by the major i ty of other nat ions—including the Soviet Union, the United States,

27space Law se/ected Bas ic Documents , 2d cd,, U.SGovernment Printing Office, 1978, p 26

and Western Europe —as legally and scientif-ically untenable. Control over the orbit by afew states would prevent free and equitableaccess to a crucial position by space-capablecountries.

The equator ia l c la im must be SPP - ‘ -- ‘ -context of various attempts by trto gain leverage over ec~ -

activities otherwise o -seven Bogota sig~ -

Ecuador, lnd~~(Brazil

‘ is., torums

..Y of special

geosynchronous use..pport among many coun-

likely to be discussed further when~~ considers the definition of outer

Ace next year, 28 and when the ITU convenesa special administrative radio conference onorbital use in 1984 or 1985.

Even if parts of the orbit cannot be appro-priated by sovereign states, there is still theproblem of allocating positions and of decid-ing competing claims to scarce orbital slots.The question here is part technical and partlegal: How much space is there, and what con-stitutes infringement? This is dependent on thestate of technology, since “infringement” isnot so much a problem of two or more objectstrying to occupy the same place as of electro-magnetic interference between nearby satel-lites (see ch. 8). SPS satellites would not onlybe very large but would, especially if usingmicrowaves, radiate a great deal of energy atradio frequencies. Each SPS would have to beallocated a position and frequency to mini-

‘“See Gorove, SPS Agreements, op. cit., pp. 14-21; and DelbertSmith, Space Stations: /nternationa/ Law and Po/icy, WestviewPre~s, 1979


mize interference with a rapidly growingnumber of satellites (see ch. 8). Many spectrumusers have worried that SPS operation woulddisrupt communications and sensing tasks,others that the initial SPSs would use up theavailable electromagnetic space, preventingexploitation by latecomers. Since the accept-able limits vary with the size and type of SPSused, the size and type of future commu-nications satellites, and advances in trans-mission technology, it is impossible to say atthis time how many SPSs could be built with-out unacceptable interference.

Allocation of frequencies and positions hasto date been the province of the ITU, whose1973 convention states that stations “must beestablished and operated in such manner asnot to cause harmful interference of othermembers, or of recognized private operatingagencies, or other duly authorized operatingagencies which carry on radio services, andwhich operate in accordance with the provi-sions of the Radio Regulations.”29 Whether theITU would have jurisdiction over noncommu-nications satellites such as SPSs is unclear.30 InNovember 1979, at the ITU’s World Adminis-trative Radio Conference, the United Statesraised the question of allocating a frequencyposition for future SPS testing; the proposalwas referred to a specialized study group forevaluation and future decision.

Allocation decisions by the ITU have beencharacterized by debate over the first-comefirst-served tradition, whereby first users havepriority in the use of frequencies and orbitalslots. Newly space-capable states as well asLDCs and others who intend to develop suchcapabilities in the future have urged, since1971, that all states have “equal rights” to fre-quencies and positions, and the ITU has calledboth the radio spectrum and the geostationaryorbit “limited natural resources” that “shouldbe most effectively and economically used.” Anumber of LDCs have proposed that space bereserved for their future use. Since there is nolegal basis for permanent utilization or owner-ship of positions, the possibility of future

zgspace Law, Op. cit., P 873oGOrove, op. cit., PP. 27-33.

reallocation clearly has considerable supportamong have-not states. Established users suchas the United States remain opposed to a prioriassignment of slots and frequencies. Again, theITU debate is part of LDC attempts to gainleverage. SPS development could be affectedby attempts of disaffected states to blockdevelopment by denying frequency alloca-tions, or by making consent contingent on con-cessions by states with the most interest inSPS.31

Environmental Considerations

The 1967 treaty states, in article VI 1, thateach state is “internationally liable for dam-age” to others caused by its activities inspace. 32 The 1973 “Convention on Interna-tional Liability for Damage Caused by SpaceObjects” amplifies on these responsibilities.33

Hence, SPS developers might face lawsuitsor other forms of grievance if the SPS damagedthe global or local environment. The extent ofvarious environmental effects is unknown andin need of further research (see ch. 8). Even ifoperation of any one SPS had no effect outsideof the state making use of it, designing aglobally marketable system to meet widelyvarying national standards could add signifi-cantly to costs. The possibility of large Iawsuitscould make insurance expensive or impossibleto procure; large risks in the nuclear industrymade it necessary for the Federal Governmentto provide insurance, and similar provisionsmight have to be made for SPSs.

Military and Arms Control Issues

The 1967 treaty commits states “not to placein orbit around the Earth any objects carryingn u c l e a r w e a p o n s o r a n y o t h e r k i n d s o fweapons of mass destruction” (art. IV) and ingeneral to carry on activities “in the interest ofmaintaining international peace and securityand promoting international cooperation andunderstanding” (art. III).34 The 1977 “Conven-

3’ Ibid , pp. 21-33,32 Space Law, op. cit., p. 28.“Ibid , pp. 49-69.“lbld , p. 26.

Ch. 7—The International implications of Solar Power Satellites Ž 157

t ion on the Prohibit ion of Mi l i tary or AnyOther Hostile Use of EnvironmentaI Modifi-cation Techniques” prohibits the activities im-plied, with “environmental modification tech-niques” defined as “any technique for chang-ing the dynamics, composition or structure ofthe Earth, including its biota, lithosphere,hydrosphere and atmosphere.” (art. 11).35 Thesegeneral principles obviously allow for criticismof some SPS designs as having weather modifi-cat ion potent ial , requir ing restr ict ions orredesign to reduce such effects. Whether anSPS’s microwave or laser capabilities wouldclass it as a weapon of “mass destruction” andhence make it illegal under the 1967 treaty isunclear, but it is very likely that such chargeswould be made in the event of SPS deploy-ment. Development of an SPS might entail re-negotiation of relevant treaties or special sys-tem design to minimize its usefulness as aweapon.

Military satellites for communications andremote sensing are currently used by severalcountries, and presumably use of the SPS plat-form for such purposes would not constitute achange in accepted practice. The Soviet Unionhas tested antisatellite satellites on several oc-casions, and the United States and SovietUnion have conducted informal talks (cur-rent ly suspended) on l imit ing ant isatel l i teweapons. The Soviet Union has complicatedmatters by stating that it considers the SpaceShuttle an antisatellite system, an unaccept-able proposal for the United States.36 U.S. AirForce involvement in the shuttle program andDepartment of Defense (DOD) plans for mili-tary missions provide Soviet negotiators withtheir rationale. Insofar as the Soviet Union ismaking this argument for bargaining purposesin the absence of a similar Soviet system(similar to Soviet proposals to ban atomicweapons in the period when it lacked its ownand to prohibit satellite reconnaissance in theearly 1960’s) such a charge could also be madeagainst heavy lift launch vehicles (HLLVs) used

jSAgreernent Governing the Activities of States on the Moonand Other Ce/estia/ Bodies, pts, 1 and 2, U.S Government Print-ing Off ice, May 1980, p. 256.

“’’Soviets See Shuttle as Killer Satellite, ” Aviation kVeek andSpace Teclmo/ogy, Apr. 17,1978, p. 17

for shuttle construction. In the absence oftheir own SPS program, obstructionist tacticsby the Soviet Union could be expected.

Although unlikely, use of the SPS fordirected-energy weaponry, either directly, oras a source of energy to be transmitted toremote platforms, or for tracking, would beregulated by the 1972 Anti- Ballistic-MissiIe(ABM) Treaty between the United States andthe US.S.R. Article V of the treaty states that“each party undertakes not to develop, test, ordeploy ABM systems or components which aresea-based, air-based, space-based, or mobileland-based.”

Use of the SPS for ABM purposes wouldhence be banned. Since any laser or micro-wave SPS is potentially capable of being soused, the Soviet Union (or the United States ifthe tables were turned) would undoubtedly in-sist on assurances and inspection provisions toprevent such developments. The ABM treatyprovides for inspection and verification by“national-technical means, ” i.e., by remotesurveillance. Onsite inspection has historicallybeen refused by the Soviet Union, although the1967 treaty, and the “Moon Treaty,” includeprovisions for mutual inspection of lunar andcelestial facilities. SPSs would need to bemonitored by Earth- and space-based recon-naissance means.

Although the ABM treaty is of “unlimitedduration” there has been considerable senti-ment in the United States for its abrogation orrenegotiation in order to provide a defense forAmerica’s increasingly vulnerable land-basedICBMS.37 Abandonment or substantial changein the treaty might allow for development ofdirected-energy weapons in conjunction withan SPS system. Renewed negotiations mayhave to take SPS development into account,perhaps by specifying SPS designs that make itunusable as a weapons system. An SPS thatused lasers as its energy-transmission mediumwould be particularly destabilizing and it ispossible that arms control considerationswould prevent such a system from being built.

-——“See Carries Lord, “The ABM Question, ” Commentary, May

1980


Common Heritage and the Moon Treaty

The 1967 treaty states, in article 1, that “Theexploration and use of outer space . . . shall becarried out for the benefit and in the interestsof all countries, irrespective of their degree ofeconomic or scientific development, and shallbe the province of all mankind.” 38 The draftversion of the Moon Treaty adds (art. IV). “Dueregard shall be paid to the interests of presentand future generations as well as to the needto promote higher standards of living and con-ditions of economic and social progress anddevelopment in accordance with the Charterof the United Nations. ”39 The exact meaning ofthese provisions is unclear, beyond a negativeduty not to interfere with the activities of otherstates or to harm their interests. A positive in-terpretation that “would impose on spacepowers the obligation either to permit othercountries to use the former’s space vehicles orto share the financial benefits of its space ac-tivities, ”40 has been made by some LDCs buthas not received widespread support. Since1958, U.S. policy has been to encourage inter-national cooperation. U.S. launch capabilitieshave been available to all countries, on a reim-bursable basis, for peaceful and scientific pur-poses.

In 1970, A. A. Cocca of Argentina proposed adraft treaty in UNCOPUOS which providedthat the natural resources of the moon andother celestial bodies be “the common herit-age of mankind.” This terminology was bor-rowed from similar language used in the Lawof the Sea negotiations in 1967 for regulatingseabed resources that lie outside of nationaljurisdiction.

In the course of the Law of the Sea negotia-tions (not yet concluded) “common heritage,”has come to mean common ownership, “bymankind as a whole” (art. CXXXVII), 14 w i t hcommercial exploitation to be regulated by ayet-to-be-formed “international regime” whichwill distribute part of the returns among par-ticipating countries. In 1970, the United States

3aSpace Law, op. cit., p. 2539 Agreement, Op, Cit., pts. 1 and 2, PP 88 -89

‘“Smith, op. cit., p. 92.“Agreement, op. cit., pts. 1 and 2, p 74

voted for a “declaration of principles” thatprohibited activities “incompatible with the in-ternational regime to be established.”42 Untilthe regime is more clearly defined, it is im-possible to tell whether current activities willbe incompatible or not. The effect of thisclimate of uncertainty and of the possibilitythat future regulations may make mining un-profitable has been to keep sea-bed miningconsortia —several of which were formed inthe 1970’s—from proceeding with the largecapital investments needed for commercial ex-ploitation.

Article Xl of the draft Moon Treaty providesfor a regime (to be established sometime in thefuture) with the following provisions:

1, The Moon and its natural resources arethe common heritage of mankind . . .

5. States parties to this agreement herebyundertake to establish an internationalregime, including appropriate procedures,to govern the exploitation of the naturalresources of the Moon as such exploita-tion is about to become feasible . . .

7. The main purposes of the internationalregime to be established shall include . . .(d) an equitable sharing by all States

Parties in the benefits derived fromthose resources, whereby the interestsand needs of the developing countries,as well as the efforts of those coun-tries which have contributed eitherdirectly or indirectly to the explorationof the Moon, shall be given specialconsiderate ion. 43

Moon Treaty opponents have argued thatthe treaty, like the proposed Law of the Sea,would delay or prevent commercial invest-ment in space activities, and would in any casesubstitute a state-run international body forprivate enterprises.44 Because of the alreadydeveloped technology for deep-sea mining(most of it U.S.), the Law of the Sea negotia-tions have become absorbed in detailed dis-cussion of the regime to be established, while

—“Agreement, op cit , pt. 3, August 1980, pp. 295-307“Agreement, op cit , pts. 1 and 2, pp 91-92,“See ‘ 1-5 Memorandum” in Agreement, op cit., pp. 377-378


in the Moon Treaty such details have been leftto the time when exploitation of lunar or othercelestial resources is “about to become feasi-ble.” The eventual outcome of the Law of theSea may have an important bearing on theshape of a future outer space regime.

Since the Moon Treaty would not apply toobjects in Earth orbit, SPS would not be direct-ly affected. However, the Treaty could haveseveral indirect effects. First of all, in severalscenarios large-scale SPS construction beyondan initial demonstration system is economical-ly feasible only if the satellites are built fromlunar or asteroidal material (see ch. 5). Suchprospects would be dependent on a regimesuch as is envisioned in the Moon Treaty,which would have to grant permission to min-ing companies to extract minerals and buildfacilities.

Secondly, it can be argued that solar energyis a celestial resource under the jurisdiction ofthe proposed regime, and that SPSs (and otherspace-craft) must be granted permission to usei t .4 5 Though such an argument is unlikely tofind general acceptance, it could be used byinterested states to try and gain additionalleverage.

Thirdly, adoption of the Moon Treaty wouldprovide a powerful precedent that could af-fect the evolution of a future SPS project. Itwould legitimize developing countries’ claimsto receive benefits on a par with states thathave actually invested in launch or construc-tion facilities, and give impetus to argumentsthat the geostationary orbit is a “common

heritage” resource requiring explicit allocationby an international body.

In the course of the Moon Treaty negotia-tions the United States was a consistent sup-porter, along with virtually all the Third Worldparticipants, of the common heritage provi-sions, while their most persistent opponent wasthe Soviet Union.46 The U.S.S.R. did not accedeto these provisions unt i l 1979. While theUnited States generally interpreted commonheritage in such a way as to allow for some de-gree of pr ivate uni lateral commercial de-velopment, the Soviet Union expressed fearsthat the treaty would lead to an unacceptablesuprastate body. The Soviet position was thatsuch a body would infringe on the sovereignrights of states. The Soviets have also opposedallowing private or nongovernmental bodies toengage in space activities. Both the 1967 treaty(art. Vl) and the proposed Moon treaty (art.IXV) provide for state supervision of and re-sponsibility for the activities of nongovern-mental entities. This “state-centric” approachis typical of Soviet attitudes in internationalnegotiations.

As a result of concerns generated by the Lawof the Sea negotiations, as well as antitreatylobbying by “pro-space” organizations such asthe L-5 Society, U.S. support for the draftMoon Treaty has been limited. U.S signaturehas been discussed in the Senate Subcommit-tee on Science, Technology, and Space, and bya special interagency committee chaired bythe State Department. Prospects for U.S. ap-proval currently appear to be slight.

“Conversation with Eilene Galloway, September 1980,

—“Agreement, op. cit., pts 1 and 2, pp 27-38

ADVANTAGES AND DISADVANTAGES OFMULTINATIONAL SPS

No matter what country or organizationwere to build an SPS, it is clear that construc-tion would involve some cooperation with andaccommodation of the interests of other states

and regions. However, from the point of -viewof any national government— and to a lesserdegree of pr ivate corporat ions as wel l– i twould be preferable, other things being equal,


to build the SPS as a strictly national ventureand to own and operate the system on a uni-lateral basis.

Unilateral Interests

From a corporate viewpoint , i t is mucheasier to do business within a country than todo so across national boundaries. Multina-tional ownership or control would complicatedecisionmaking, reduce f lexibi l i ty , and in-troduce a multitude of political strains thatany company would prefer to avoid. To the ex-tent that foreign markets are attractive, thecompany wouId prefer to retain domestic own-ership and to sell completed units abroad,minimizing foreign entanglements.

From the point of view of governments thatmight consider investing in SPS, the desire todo so alone would be very strong, for reasonsof prestige, security, and economics. At pres-ent only the United States and the SovietUnion could even consider such a unilateral ef-fort. In the longer term, however, it is con-c e i v a b l e t h a t a E u r o p e a n c o n s o r t i u m o rperhaps even a single European state—mostl ikely France– could also undertake such aproject. So could Japan, with possible cooper-ation from China, South Korea, and otherregional powers with technical expertise andfinancial resources.

Is it likely that the United States or theSoviet Union would build an SPS in the nearfuture? Such a program would be undertakenonly if there were serious doubt that alter-native energy sources will be available in thefuture, or that their costs will be acceptable.This would have to mean that the C02 and en-vironmental problems of large-scale coal usewere seen to be acute and imminent, or thatnuclear reactors were deemed unacceptabledue to a major accident and public disap-proval. In addition, alternatives to the SPSsuch as fusion, ground-based solar cells, andpossible other future technologies, would haveto fail to fill the gap (see ch. 6). In the event ofsome such crisis SPS studies must be sufficient-Iy advanced to provide very high assurancethat such a system would work. Given this

combination of events, and if cooperation withforeign governments or corporations is re-jected because of fears that it might slowdown the project or otherwise reduce i tsdomestic usefulness, it is possible that aunilateral effort would be undertaken.

There are several other factors that might in-crease the attractiveness of a unilateral crashproject similar to the Manhattan or Apollo pro-grams. Three requirements for such decisionsare: 1 ) a crisis, requiring immediate action,which threatens basic national interests; 2) theexistence of a workable plan to resolve thecrisis; 3) decisive leadership by persons in posi-tions to implement such plans. ” In the Man-hattan and Apollo cases, the crises involvedchallenges to national interests that placed apremium, not only on developing the atomicbomb or the ability to go to the Moon, but ondoing so first.

The SPS would have important economic,prestige, and security implications. Unilateraldevelopment by the Soviet Union or theUnited States would provide a strong impetusfor the other to do so as well, as long as theproject could also be just i f ied on othergrounds. The strength of this impetus woulddepend on the state of future U.S.-Soviet rela-tions. In the 1950’s nuclear weapons and theirdelivery systems were seen as vital to the ex-istence of the state; the space programs of the1960’s as symbolic of each state’s social andeconomic superiority. It is unlikely that theSPS would be as crucial to East-West competi-tion as these earlier technologies, unless theSPS or the launchers needed to build it be-come vital elements of military systems. Forthe reasons given in the next section, Nationa/Security Implications of SPS this is possiblebut unlikely. Hence an equivalent desire tobuild the first system–an SPS “race”- is im-probable.

Within the United States certain interestswould favor unilateral as opposed to multilat-eral development. Businesses likely to benefitfrom development, such as aerospace indus-— — .

“]ohn 1 ogsdon, The Decision To Go To rhe Moon (Cambridge,M,tss Ml T Press, 1970), p 181


tries or large construction firms, might prefer aunilateral effort that would provide them withmost or al I of the contracts, as well as the pros-pect of foreign sales. However, others mightfear that a unilateral development would dis-courage foreign buyers. Some utilities and oilcompanies might oppose an SPS altogether ifit competes with energy sources in which theyhave already invested. Since unilateral devel-opment would almost undoubtedly mean agovernment-dominated and financed project,such businesses would be likely to argue thatthe SPS is unfairly competitive and to demandcompensation.

In the Soviet Union there is no private sectorand hence no question of public v. privatedevelopment. Though it is possible that non-Communist states such as India and France,both of whom have engaged in cooperativespace projects with the Soviet Union before,might participate in small ways, it would beunprecedented for the Soviet Union to engagein extensive joint planning or operations withnonallied states. Such cooperation in sensitive,high-technology areas involving space ca-pabilities, which in the Soviet Union are run bythe armed forces and considered top-secretmilitary programs, is especial ly unl ikely .Hence an international SPS program is not areal option for the Soviet Union, given its pres-ent political and economic institutions.

Within both the United States and SovietUnion, the military may argue for a unilateralprogram in order to enhance SPS’s militaryusefulness, which would be destroyed if sen-sitive information had to be shared amongneutral partners or partners who could not betrusted not to reveal technical or other detailsto unfriendly states. In the United States,resistance to military involvement is likely tobe strong, partly to avoid foreign charges ofaggressive intent, and also to prevent possiblemilitary interference in the project’s efficien-cy, as with the Space Shuttle.48 However, giventhe military’s role in the Soviet space program,

“The price for Air Force support of Shuttle funding in Con-gress was substantial redesign of the original Shuttle model, low-ering performance and increasing costs See Jerry C rey, Enter-prise (New York: William Morrow & Co , 1979), pp. 66-68.

such arguments are likely to be less tellingthere than in the United States. Although vari-ous Soviet ministries would seek a say in SPSdevelopment, none has the technical or mana-gerial competence to displace the military insuch a project.49

In the United States, the Government spon-sors two largely separate space programs, acivilian one run by the National Aeronauticsand Space Administration (NASA), and a mili-tary one run by the Department of Defense.Both draw extensively on expertise and ex-perience from a large number of private firms.While an SPS project in the Soviet Union couldnot help but be dominated by the military, aU.S. project, even one run by the Government,could be shared between the military, Gov-ernment-civilian, and private sectors. Variouscombinations could be developed to provide adesirable mix between public and private, mili-tary and civi l ian authori t ies.50 In the past,Government-sponsored projects that mightprovide guidance and precedent for an SPSprogram have included the Panama Canal, theTennessee Valley Authority, and the InterstateHighway System. (See ch. 9, Financing, Owner-ship, and Control. ) What is important is theflexibility available to U.S. planners, a flexibili-ty not found in the Soviet Union, which, if amult inat ional ef fort is preferred, makes i tpossible to accommodate international part-ners on various terms.

Both Western Europe and Japan have moreurgent requirements for reliable energy sup-plies than the two current space powers. Theimpetus for SPS development wouId be similarto that for the United States, but the need ismore imminent, and the costs of alternatives,in the absence of indigenous fossil fuels, arehigher. Could an SPS be built in an acceptableperiod without extensive U.S. assistance(assuming Soviet assistance is improbable)?

“See Soviet Space Programs 1977-7975, vol. 11, ch, 2, “Orga-nization and Administration of the Soviet Space Program, ”August 1976, pp. 63-82.

‘°For discussions of these issues, see Peter Vajk, 5PS Finan-c;al/Management Scenarios, DOE/NASA contract No. EG-77-C-01 -4024, October 1978, Herbert Kierolff, SPS F;nan-c;al/Management Scenarios, DOE/NASA contract No. EG-77-C-01 4024, October 1978.


The requisite technical and financial base isavailable; strong aerospace industries exist; na-tional and multilateral space programs, suchas the European Space Agency (ESA), are inplace. However, both ESA and Japan lack thedepth of U.S. industry’s aerospace expertise,its worldwide tracking and relay networks, andabove all experience in and development ofmanned space-vehicles. The most sophisti-cated non-American launch vehicle is ESA’sAriane, which is still being test-flown and isscheduled to begin commercial operations in1982. 5’ The Ariane is a high-quality three-stageexpendable booster, but it is far smaller thanthe large U.S. Saturn rockets used for theApollo program. And it is far behind the U.S.Space Shuttle in capabilities, payloads, andcost effectiveness (at least to LEO). Since theShuttle itself is too small and expensive forfull-scale SPS construction, ESA is at least twogenerations of vehicles away from being ableto develop an SPS unilaterally. Producing therequisite lift capabilities in an independentprogram would be extremely costly and time-consuming.

It is clear that any unilateral SPS programdepends on a dramatic and unpredictable in-crease in the sense of urgency about mediumand long-term energy supplies. Even if such anincrease were to occur, such efforts would bevery expensive for any one country or region toundertake, especially since crash programs arenecessariIy more expensive than ordinary ones;money is traded for time.

Multilateral Interests

There are three reasons why interested par-ties may wish to abandon their preference forautonomy in favor of an international effort.These are: 1) to share the high costs and risks;2) to expand the global market; 3) to forestallforeign opposition and/or promote interna-tional cooperation.

costs

The exact costs of developing, manufactur-ing, and operating a SPS are unknown; NASA

“Edward Bassett, “Europe Competes With U.S. Programs, ”Aviation Week and Space Technology, Mar 3,1980, p, 89.

estimates a 22-year, $102 billion program forthe reference design.52 (See ch. 5, Costs. ) Al-though the R&D costs would be much lowerthan construction costs, they would be thehardest to finance, and the ones where interna-tional cooperation would be most valuable.The number of satellites needed for a globalsystem would clearly be much larger than for aU.S. system alone. However, the R&D/proto-type costs are essentially the same whether thesystem is unilateral or multilateral. Since thevery long 30-year period of investment beforepayback is the project’s weakest link, it wouldbe desirable to spread these costs between alarge number of possible investors. And bywidening the available pool of capital and ex-pertise, an international effort would have lessof an inflationary impact on resources, thuskeeping costs down.

However, it should be realized that an inter-national consortium, whether involving privatefirms or government agencies, will tend gen-erally to increase the overall costs. Under thebest of circumstances there are costs associ-ated with doing extensive business acrossborders, with coordinating efforts in differentlanguages and geographic areas, and with bal-ancing the divergent national interests offoreign partners. Without careful managementand a high degree of cooperation from thestates involved, these extra inefficiencies caneliminate any advantage gained from interna-tionalizing the project. The experience of Euro-pean collaborative efforts has been that costsrise as the large number of participants in-creases the managerial superstructure andproject complexity .53

The Global Market

We have previously discussed the SPS’s po-tential global market. An international venturemay improve the marketing prospects of thesystem. First of all, potential users and buyerswouId be less concerned about becoming de-pendent on a particular country or corpora-t ion, which may infr inge on nat ional sov-.——

5*K Ierolff, op. cit., pp. 4-55 JTestlmony of Dr. Wolfgang F i n k , /nternationa/ Space Ac-

tivities, 95th Cong., November 1978, U.S. Government PrintingOffice, p 12

Ch. 7—The lnternational Implications of Solar Power Satellites ● 163

ereignty. Many states, especially LDCs, areconcerned about such a situation, particularlywith regard to U.S. firms. Over the past 15 to20 years, LDCs have made great efforts to gainindigenous control over local industries andresources, often resorting to nationalizationand expropriation. The accumulation of finan-cial and legal expertise by LDC governmentsmeans that future dealings with foreign firmswill be more cautious and equitable than inthe past. Also, it is often politically more feasi-ble for a neutral or nonalined state to deal withan internationally controlled consortium thanwith a U.S. or Japanese or West European firm,especially when internal opposition to suchrelationships is strong.

A consortium that offered direct partici-pation and ownership to a large number ofstates would improve its marketing positioneven more. Such participation/ownership, evenif on a small scale, would help to familiarizemembers with the organization’s operationand finances, and assure potential buyers thatthey were not being deceived. A financialstake would provide an incentive to see thatthe system worked efficiently and was suitedfor the needs of a variety of users.

Widespread participation by many countrieswith different financial stakes and energy re-quirements would also present a host of prob-lems. Even small investors could be expectedto lobby for a proport ionate share of thebenefits, including profits and contracts, andfor a say in policy and management decisions.Investors with similar interests can be ex-pected to band together. Often, small-stakeparticipants with less to lose are willing to useany available forum to further ideological oreconomic interests unrelated to the business athand. A balance must be struck between theadvantage of open participation and the dan-ger that such participation could underminethe organization’s credibiIity and competence.

Forestalling Opposition,Promoting Cooperation

Because of the importancethe size of the financial stakeSPS participants could expect

of the SPS andinvolved, majorthat nonpartici-

pants would use their leverage for concessionsin unrelated political or economic areas. How-ever, mere participation would not forestallopposition. If member interests are not mutu-ally compatible, opposition is only movedfrom without to within. The best check on in-ternal obstructionism would be for the majorparticipants to indicate their willingness to goit alone, if necessary, rather than allow internalobstacles to destroy the project. Since orga-nizations quickly develop their own constit-uencies, within and without governments,which have an interest in maintaining the orga-nization, a credible threat to go it alone mustbe backed up by national leaders and by in-vestment in the requisite systems.

Possible Models

Intelsat, Inmarsat

How might such an organization be con-structed, and what are the types of problemsthat might be faced? Here it is helpful to lookat historical examples of international orga-nizations in the space and energy fields. Wewill look briefly at Intelsat and Inmarsat; atcooperative efforts in nuclear power; and atthe European Space Agency (ESA).

Of existing bodies, Intelsat and its near-relative, Inmarsat, have been mentioned mostoften as possible models for an internationalSPS project. Intelsat is attractive because ithas been efficient and profitable, and becauseit has succeeded in including a large number ofparticipating states.

Intelsat was founded in 1964, largely at theprompting of the United States, to provide in-ternational satellite telecommunication serv-ices. The initial agreement provided for jointownership and investment in proportion to theuse of the system by each participating coun-try, and for renegotiation in 5 years to take ac-count of experience and new developments. 54

At first, Intelsat was dominated by the UnitedStates through its semipublic participant, Com-sat; LDC participation was minimal, and the

“Jonathan Galloway, The Po/;t;cs and Technology of Sate//;teCommunications (Lexington, Mass.: Lexington Books, 1972),p 75


Soviet Union and East Bloc countries refused,to join, preferring to establish a separate orga-nization, Intersputnik. The permanent agree-ments reached in 1971 reduced Comsat controland made it easier for low-use countries to par-ticipate. In 1979, Intelsat had 102 members,with the U.S. share being 24.8 percent.55 (S eeapp. E.)

Inmarsat is designed to provide positioningand maritime services between ships and ship-to-shore. Organized similarly to Intelsat, it isexpected to begin operations in 1981, leasingits initial satellite services from lntelsat.56 (Seeapp. E.)

Though Intelsat has functioned relativelysmoothly and has shown a good return on in-vested capital, serious disagreements betweenparticipants have arisen. Many of these dis-agreements have revolved around the allo-cation of procurement and R&D contracts,with member countries competing for pres-tigious and high-value shares. Given the pre-dominant position of U.S. aerospace firms,much of the pressure has been for equitableshares for European and Japanese companies.However, some participants, especially LDCsand others without indigenous aerospace ca-pabilities, have objected to distributing con-tracts on a geographical or political basis,charging that it drives up costs.57 Non-U. S. con-tract shares have risen over time (23 percent ofIntelsat 5, the latest model satellite, is foreignbuilt), 58 and future use of ESA’S Ariane launch-er and purchase of European communicationsatellites may raise this significantly. (See app.E.)

What do the Intelsat and Inmarsat modeltell us about a possible “lntersunsat?” Therelatively smooth functioning of Intelsat islargely a result of its initial organization, whichhad certain peculiarities not likely to be re-peated in the future.

55 Comsat Annual Report 1979, p. 23.“’’Operating Agreement on Inmarsat, ” 1976; in Space Law,

p. 445.Szjoseph N, pelton, G/oba/ communicat ions %’te//jte po/icY:

Intelsat, Politics, anci Functionalism (Mt Airy, Md.: LomondBooks, 1974), p. 76.

‘a’’lntelsat Being Readied for November Launch,” AviationWeek and Space Technology, Oct. 27,1980, p 51.

Above all, Intelsat came into being throughthe. dominant interest and investment of asingle participant, the United States. U.S.determination to institute a global communi-cation satellite system was due in large part tothe Kennedy administration’s desire, at a timewhen the Soviet Union seemed superior inmanned and unmanned space capabilities, toachieve a space success before the Soviets thatwould pay off in terms of global prestige andthe furtherance of U.S. national interests. The1958 Nat ional Aeronaut ics and Space Actwhich establ ished NASA proclaimed thatspace activities “should be devoted to peace-ful purposes for the benefit of all mankind.”59

In addition to the scientific and commercialbenefits, improved international communi-cation was seen as a foreign policy plus for theUnited States, that would involve other statesas participants under U.S. leadership. Thetechnology for such activities was well ad-vanced and judged to be superior to that of theSoviet Union.

The centralized management structure thuscreated, combined with U.S. technical leader-ship and its status as the largest single user ofthe system, gave Intelsat initial national sup-port that was vital in allowing it to operate ef-ficiently and with a minimum of delays. Thepromise of future renegotiat ions placatedthose, such as France, who objected to the ini-tial phase of U.S. dominance. By contrast, theestablishment of Inmarsat, despite its closeadherence to the Intelsat model, took 4 yearsof negotiations and some 9 years before thestart of actual operations.

At the outset of Intelsat negotiations in1963, and even at the time of renegotiation in1969-71, the U.S. position vis-a-vis Europe andthe Third World was much stronger than it hasbeen since or is likely to be again, not only inspace technology but in general economic per-formance and military strength. This across-the-board preeminence made palatable-a U.S.position that would today probably not betolerated.

5“’National Aeronautics and Space Act,” 1958; in Space Law,p 499


In the foreseeable future, U.S.-Europeanequivalence in technical and economic capa-bilities and the increased self-confidence ofthe Third World countries, who were effective-ly excluded from the initial Intelsat arrange-ments, will make a repeat of the U.S. positionimpossible. With regard to an SPS, the UnitedStates would not necessarily be the largestuser, nor would it have a monopoly on engi-neering expertise. And the political impetusprovided by Soviet competition, which wasvital to the formation of Comsat and Intelsat,is likely to be missing or muted.

The swift and effective establishment of ln-telsat depended on several other factors. Onewas the prior existence of international and na-tional entities dealing with global communica-tions. Bodies such as the ITU provided tech-nical background and legal precedents fordealing with communication satellites, and na-tional telecommunications agencies had longexperience with short-wave and cable trans-missions. No such equivalent exists for the SPS.

The initial costs of Intelsat were compara-tively low; as of 1980 (through 16 years ofoperation) a total of somewhat over $1 billionhad been invested in R&D and procurement. Inaddition, the basic research had already beendone, and paid for, by the United States; it wasa proven technology with a predictable mar-ket. The SPS would be several orders of magni-tude more expensive, would take decades toproduce, and is far riskier. One consequenceof communication satellites’ low cost—andthe existence of established communicationentities—was that the basic decisions, both atthe beginning and later on, were made by ex-pert bodies with little public awareness. 6o Thisprevented sharp polar izat ion and al lowednegotiators to give and take without riskingoutcries at home. SPS negotiations would nottake place in this atmosphere. As one observernotes, “An SPS is not likely to come into beingthrough the nonpolitical activities of technicalagencies . . . Decisions about SPS at the inter-national level will be made . . . by the politicalleaders of major nation-states in the context of

‘OPelton, op. cit., p. 44

international political debate. ”61 The large sizeand importance of SPS contracts would createstrong pressures for geographical allocation;here the experience of the North AtlanticTreaty Organization (NATO) may be more rele-vant than that of Intelsat.

The above is not meant to dismiss Intelsat’sexperience. Valuable lessons from Intelsat arethe importance of corporate-style independentmanagement; weighted voting by investmentshare and usage; and interim arrangementsthat allow a project to begin work and gain ex-per ience before establ ishing a permanentstructure. And the positive example of Intel satand the experience gained in its operation willprove helpful in the future.

Other Models

Besides Intelsat, with its distinctive com-bination of state and designated-entity par-ticipation, there are other possible models forinternational cooperation, including: 1) joint-ventures by privately or Government-ownedmultinational corporations, on the model ofAramco, or the recently formed Satel l i teBusiness Systems, jointly owned by Comsat,IBM, and Aetna Insurance, 2) state-to-stateagreements coordinating national space pro-grams, such as ESA and its predecessors, ELDOand ESRO; 3) international agreements on thedevelopment and use of atomic power, such asEuratom; 4) U.S. bilateral arrangements be-tween NASA and foreign agencies or com-panies.

PRIVATE CONSORTIUM

Agreements for joint financing and manage-ment by nationally based companies can pro-vide extensive informal coordination acrossboundaries and facilitate the raising of capitalon diverse financial markets. (See ch. 9, Financ-ing, Ownership, and Control. ) Two major dif-ficulties would face such an attempt. From thecompany’s viewpoint the very high initial in-vestments and the uncertain legal and regula-tory constraints would inhibit commitmentwithout government guarantees. Many dis-

“john Logsdon, “International Dimensions of Solar Power Sat-ellites Collaboration or Competition?” July 1980, p 3.


cussants have concluded that public sector fi-nancing would likely be essential for any SPSproject. ’z From the state perspective, especial-ly outside the United States, there would be re-luctance to rely on private sector developmentand control of energy supplies, as well aspotential antitrust problems (especially in theUnited States) caused by a concentration ofcompanies.

ESA

Within Western Europe there have beenongoing efforts to coordinate national spaceprograms so as to compete with the UnitedStates and the Soviet Union. In the early 1960’stwo organizations were founded: ELDO (theEuropean Space Vehicle Launcher Develop-ment Organization), aimed at designing andbui lding a European launch vehicle ( the“Europa” rocket); and ESRO, (European SpaceResearch Organization) to conduct basic re-search. Both groups, and especially ELDO, suf-f e red f rom a l ack o f d i rec t ion and f romdivergent national interests. ’3 Allocation ofcontracts was based on the principle of “fairreturn;” contributions to the organization werein proportion to each state’s GNP, and con-tracts were supposed to be let in similar ratios.This produced intense disagreements anddelays, exacerbated by cost increases whichhad to be allocated evenly among the par-ticipants.

In the late 1960’s Europe began to pay in-creased attention to the so-called “technologygap” between it and the United States. In 1967,J. Jacques Servan-Schreiber’s book The Amer-icean challenge “polemicized the U.S. eco-nomic invasion of Europe and aroused a pop-ular interest in technology comparable to theSputnik aftermath in the United States.’’ 64I n -terest in joint space efforts increased; thefailure of ELDO to produce a reliable Europarocket was heavily criticized, with France andGermany claiming their willingness to produceit on their own.

‘*See Vajk and Kierolff for further discussion‘3 See Mihiel Schwarz, “European Policies on Space Science

and Technology 1960-1978, ” Research Policy, August 1979, pp.205-242,

“Henry Nau, Nationa/ Po/itics and /nternat;ona/ Technology(Baltimore: Johns Hopkins University Press, 1974), p. 55

The late 1960’s also produced strong pres-sures, as in the United States, for projects witheconomic payoffs, rather than abstract re-search or prestige programs. After Apollo, theUnited States began to look for ways to reducethe costs of its proposed Space TransportationSystem. One way was increased cooperationwith Europe. While France remained suspi-cious that such offers were designed to fore-stal I independent European programs, Ger-many welcomed NASA proposals for joint de-velopment as a way to gain access to U.S. tech-nology and to use of the Space Shuttle. Hence,whiIe France continued to emphasize launcherdevelopment, Germany turned to productionof Spacelab for NASA.

In 1973, ESRO and ELDO were joined to-gether as the 9-member European Space Agen-cy. Its major projects to date have been: 1) theAriane launcher, a $1 billion effort which is 64-percent French f inanced and f lown fromFrance’s spaceport i n G u i a n a , S o u t hAmerica; 65 and 2) Spacelab, an $880 millionproject, 55-percent German financed, beingbuilt in West Germany. Other ESA projectshave included regional remote sensing, mete-orological, and maritime satellites, and a re-gional communications satellite (L-Sat) beingdeveloped under the guidance of Great Bri-tain. 66

The formation of ESA has not eliminatedintra-European difficulties and the problem ofcoordinating national programs. A report in ln-teravia charges that “individual states are tir-ing of the paper-passing and consensus-seekingthat is involved in getting programs started andkeeping them alive within the framework of aninternational civil-service organization.’’” OneresuIt may be a turn towards commercial alter-natives. With the completion of Ariane a newfirm called Arianespace has been formed,made up of European industries, banks, andthe French National Space Agency, to marketthe launcher commercially and in competition

“’’The French Space Effort, ” Interavia, June 1979, p, 508.“Edward Bassett, “ESA Planning New Telecommunications

Satellite,” A v;ation Week and Space Technology, Dec 31, 1979,p 12

“’’European Space Programs: An Industrial Plea for IntegratedEffort,ll Interav;a, August 1979, p. 785,


with the U.S. Space Shuttle. 68 If successful,Arianespace will provide an example of howan internationally financed and developedspacecraft can be turned over to a commercialoperating group, which could be a model forsimilar development of the SPS. However, all-in-all the history of European collaborationprovides more “dont 's” than “do’s” for afuture SPS effort.

NUCLEAR POWER

Internat ional nuclear cooperat ion is theonly model that compares with the SPS in itsf inancial and pol i t ical scope, though thesecurity aspects of nuclear power are largelyunique. Like SPS, nuclear power is a baseloadelectricity source requiring large investmentsand a high degree of technical competence,with widely perceived environmental dangers.

The overall picture of nuclear cooperationshows a field where development and opera-tion, though expensive, is not prohibitively so,and where considerations of national prestigeand security are extraordinarily high. “Have”countries have had Iittle reason to promote thespread of nuclear technology, except as a prof-itable export or a form of foreign aid. The ex-pense of initial development has been justifiedas a military necessity (as in the U.S. submarinereactor program). Cooperation is largely moti-vated by the need for agreed-on internationalstandards and regulations to prevent accidentsand inhibit proliferation. Strictly economic orenergy-supply considerations have played asmall role, except as window-dressing, whilepolitical and competitive needs have been theprime movers. Nuclear development in ThirdWorld countries, such as Brazil and India, has

“’’New Commercial Organization to Take Ariane Responsibili-ty,” Aviation Week and Space Technology Apr. 7,1980, p. 45,

been especially motivated by noneconomicconsiderations. 69

Development of an SPS should not sufferfrom the extreme obstacles to positive coop-eration faced in the nuclear field: the militaryuses would be less important, the costs muchhigher, and the economic need greater. The in-tense politicization of nuclear developmentshows an extreme case of the forces that cancome into play during the development of amajor new technology.

U.S. BILATERAL ARRANGEMENTS

The United States has been very successfulin establishing useful bilateral arrangementswith foreign governmental agencies and orga-nizations, such as ESA. NASA has been em-powered to enter into exchanges of informa-tion and services, in coordination with otherparts of Government, such as the State Depart-ment. NASA has provided launch services,technical assistance, and remote sensing(Landsat) imagery to a large number of foreigncustomers.’” The network of relationships builtup over the years could be helpfuI in promot-ing a multilateral SPS. Direct bilateral co-operation with major potential partners inEurope and Japan might be the best way to ini-tiate foreign cooperation and create a climateconducive to the expansion of the enterprise,especially in the initial less expensive R&Dstages. Such agreements would take substan-tially less time to negotiate than regional orglobal ones. ”

“June Sabato and Jairam Ramesh, “Atoms for the ThirdWorld, ” Bu//et;n of Atomk Scientists, March 1980, p. 39.

‘“Stephen M. Shaffer and Lisa R. Shaffer, “The Politics of in-ternational Cooperation: A Comparison of U.S. Experience inSpace and Security,” Monograph Series in Wor/d Affairs, vol. 17,book 4, University of Denver, 1980, pp. 15-26.

“Go rove, op. cit., p. 50,

NATIONAL SECURITY IMPLICATIONSOF SOLAR POWER SATELLITES

The potential military aspects of an SPS will fears that the satellite will be vulnerable tobe of major concern to the international com- attack, or that it may be used for offensivemunity and to the general public. There are weapons (see ch. 9, Public Opinion). Such con-


cerns may be decisive in determining the paceand scope of SPS development, and the modeof financing and ownership that is used. Thereare three basic aspects to consider: 1) SPSvulnerability and defensibility; 2) the militaryuses of SPS launch vehicles and constructionfacilities; and 3) direct and indirect use of SPSas a weapons system or in support of militaryoperations. Of these it is the second, the exten-sive capability of new launchers and largespace platforms, that will constitute the mostlikely and immediate impact.

Vulnerability and Defensibility

There are two main segments of any SPS, theground receiver and the satellite proper. Sincereference-system rectennas or mirror-systemenergy parks would be very large and com-posed of numerous identical and redundantcomponents, t h e y w o u l d b e u n a t t r a c t i v etargets; the smaller antennas of other designswould be slightly more vulnerable. The satel-lite segment would be vulnerable in the waysoutlined below, but in general no more so thanother major installations. Its size and distancewould be its best defenses.

Would SPS Be Attacked?

The reasons for attacking a civilian SPSwould be that it is expensive and prestigious,not easily replaceable, and that it supplies anessential commodity, baseload electricity. Indetermining whether to target an SPS in theevent of hostilities, the crucial considerationwould be how much of a nation’s or region’selectricity is supplied by SPS. In mostdeveloped countr ies, ut i l i t ies maintain areserve of approximately 20 percent of theirtotal capacity, in order to guard againstbreakdowns and maintenance outages. If SPSsupplied no more than the reserve margin, itsloss could be made up; however, given an SPSsystem consisting of many satelIites particularregions or industries would be Iikely to receivemore than 20 percent. Making up for losseswould require an efficient national grid tot rans fe r power to highly af fected areas.Increased use of high voltage transmissionlines and other measures should increase U.S.

ability to transfer power. However, in manycountries, especially LDCs, SPS losses mightnot be easily replaceable since SPSs, if used,would be likely to provide more than 20 per-cent of total capacity on a national basis.

An attack on SPS would also depend onother factors. If the attacker relies on its ownSPSs, it may fear a response in kind. If thesatellites were owned by a multinational con-sortium the attacker might be hesitant to of-fend neutral or friendly states involved. If theywere manned— it is unclear whether perma-nent personnel would be required for SPS — theattacker might be reluctant to escalate a con-fIict by attacking manned bases.

The unprecedented position of the SPS,located in orbit outside of national territory,gives rise to uncertainties as to how an attackwould be perceived and responded to. If theSPS is seen as analogous to a merchant ship onthe high seas, attacks would be proscribedunless war were declared and outer space wereproclaimed a war zone. Otherwise, any attackwould be tantamount to a declaration of war.In practice, however, experience has shownthat attacks on merchant vessels have notcaused an automatic state-of-war, though theyhave often played a crucial part in bringingone about.

It is more likely that the SPS, because of itsfunction and/or its stationary position (for cer-tain designs), would be perceived as similar toa fixed overseas base or port rather than a ship.An attack would then be taken more seriously,especially if lives were lost. It will be impor-tant for national leaders to clarify what statusan SPS would have, particularly in times ofcrisis. A low priority assigned to SPS could en-courage enemy states to attack it as a way ofdemonstrating resolve or as part of an escala-tor response short of all-out war.

How Could SPS Be Attacked?

There are essentially five ways the satelliteportion of an SPS could be destroyed or dam-aged: 1) ground-launched missiles; 2) satellitesor space-launched missiIes; 3) ground or space-based directed-energy weapons; 4) orbital

Ch. 7—The International Implications of Solar Power Satellites Ž 169

debris; 5) disruption or diversion of the energytransmission beam.

A missile attack from the ground on a geo-synchronous SPS would have the disadvantageof lack of surprise, due to the distances in-volved and the satellite’s position at the top ofa 35,000 km gravity well; missiles would takeup to an hour or more to reach, geosynchro-nous orbit. An attack from prepositioned geo-synchronous satellites would be faster and lessdetectable. However, a laser or mirror SPS inlow orbit could be reached from the ground ina matter of minutes. Lasers or particle beams,which might be used to rapidly deface thesolar celIs or mirrors rather than to cause struc-tural demage, would have virtually instanta-neous effect.

Placing debris in SPS’s orbital path, but mov-ing in the opposite direction —such as sanddesigned to degrade PV cells or mirrors–would have the disadvantage of damagingother satellites in similar orbits, and of makingthe orbit permanently unusable in the absenceof methods to ‘sweep’ the contaminated areasclean. The relative ease and simplicity of thismethod, however, could make it attractive toterrorists or other technically unsophisticatedgroups. Any explosive at tack could havesimilar drawbacks, although since the result-ant debris would be traveling in the samedirection as most other satellites (which movewith the Earth’s rotation) the ensuing damagewould be SIight.

I f technical ly feasible, disrupting SPS’smicrowave or laser transmission beam, eitherby interfering directly with the beam or itspilot signals, or by changing its position so thatit misses its receiving antenna, would be ahighly effective way to attack the SPS. Sincethe effects would be temporary and reversible,such an attack might be favored in crisis situa-tions short of all-out war. Disruption usingmetallic chaff would be ineffective against amicrowave beam, due to its very large area.Laser beams could be temporarily deflected byclouds of small particles or by organic com-pounds that absorb energy at the appropriatefrequency. Electronic interference possibilities

for lasers or microwaves cannot be presentlypredicted.

A missile attack with a conventional war-head might be difficult due to SPS’s very largesize and redundancy. The most vulnerablespot on the reference and other photovoltaicdesigns would be the rotary joint connectingthe antenna to the solar cell array. Lasertransmitters would be more vulnerable due totheir smaller size, though they would also beeasier to harden. Attackers would be temptedto use nuclear weapons, either directly on thesatellite, or at a distance. I n space a large (onemegaton or more) nuclear blast at up to 1,000km-distance could cause an electrical surge inSPS circuitry (the electromagnetic pulse (EMP)effect) sufficient to damage a photovoltaicS P S72 (though it would have no effect on amirror-system). Such an attack would be par-ticularly effective against a large SPS system,as it could destroy a number of satellitessimultaneously. However, like an orbital debrisattack, it has the problem of damaging allunhardened satellites indiscriminately withinthe EMP radius. Furthermore, any use ofnuclear weapons would constitute a seriousescalation of a crisis and might not be con-sidered except in the context of a full-scalewar.

Could the SPS Be Defended?

Defense of orbital platforms can be accom-plished in three ways: 1) evasion; 2) hardeningagainst explosive or electronic attack; 3) anti-missiIe weaponry.

All of the SPS designs being consideredwould be too large and fragile to evade anincoming attack. SPSs may be equipped withsmall station-keeping propulsion units but notwith large engines for rapid sustained move-ment.

Hardening against explosive or debris attackwouId require rigid and heavy plating. Such ef-forts would be prohibitively costly, exceptperhaps for a few highly vulnerable areas.

‘*Peter Vajk, “On the Military Implications of Satellite PowerSystem s,” Linco/rI Proceedings, April 1980, pp. 506-507

83-316 0 - 81 - 12


Hardening against EMP bursts or electronicwarfare would require heavier and redundantcircuitry as well as devices to detect and blockjamming attacks. I f incorporated in SPSdesigns from the beginning, these might besufficiently inexpensive to justify inclusion.Different designs may differ in their vulner-ability to such attacks —the photoklystronvariation, for instance, would be less suscep-tible to EMP than the reference design.

Antimissile weaponry, whether in the formof missiles or directed-energy devices, couldbe placed on the SPS to defend against missileand satellite attack. Though potentially highlyeffect ive against incoming missi les, suchweapons would be useless against long-dis-tance nuclear bursts or remote lasers. Further-more, they would have unavoidable offensivestrategic uses against other satellites and inter-continental ballistic missiles (ICBMs), andwould hence invite attack. For these reasonsmajor defensive systems are unlikely to beplaced on civilian SPSs. Attacks would bemore effectively deterred by political arrange-ments and by the use of separate militaryforces.

Who Would Attack?

In most instances an attack could only becarried out by a technically sophisticated na-tion with its own launchers and tracking sys-tems. Threats by such a space-capable poweragainst other space-capable powers —say bythe U.S.S.R. against the United States—arepossible in the context of a major crisis or ac-tual war where the attacker is willing to riskthe consequences of i ts act ions. Threatsagainst inferior or nonspace-capable states,such as SPS-using LDCs, might be made at amuch lower crisis threshold.

It is unclear which states will be capable ofprojecting military power into space over SPS’Slifetime. It is possible that technical advanceswill allow even small countries to purchaseoff-the-shelf equipment enabling them to at-tack an SPS, in the way that sophisticated sur-face-to-air missiles (SAMs) are now widelyavailable to attack airplanes. However, it ismore probable that, over the next 50 years,

such capabilities will remain in the hands ofthe larger developed nat ions ( including anumber of countries that can be expected toenter this category in the future).

The state of technology obviously bears onthe question of whether terrorists or criminalscould attack an SPS. Politically motivated ter-rorists are generally strong on dedicated man-power, not technical expertise. The SPS wouldbe a symbolic high-visibility target, but ter-rorists would be more likely to attack SPSlaunch-vehicles, which would be vulnerable tosimple heat-seeking missiles, than to threatenthe SPS directly.

However, a believable threat of direct at-tack by terrorists or small powers could be aspur to defensive measures such as hardeningor antimissiIe devices, which wouId not stop anattack by a major power but might be effectiveagainst lesser threats.

Sabotage of the SPS through the construc-tion force, either for political purposes and/orfor ransom, could not be ruled out. Carefulscreening of construction workers — whowould be few in number— can be expected,along with supervision while in orbit. The un-avoidable conditions of life and constructionin space would make it difficult, especially atf i rst , to smuggle explosives or sabotage-devices into orbit. However, a major expansioninto space involving large numbers of person-nel would, in the long run, provide opportuni-ties for sabotage that probably cannot now beforeseen.

Under current conditions any installation, inspace or on the ground, is vulnerable to long-range missiles, or to dedicated terrorist groups.Reasonable measures to mitigate threats toSPS should be undertaken, but the dangersthemselves cannot be eliminated.

Current Military Programs in Space

At present a number of nations use space formilitary purposes. The United States andSoviet Union operate the bulk of military satel-lites, but China, France, and a few other coun-tries also have military capabilities. The preva-

Ch. 7—The International implications of Solar Power Satellites • 171

lent uses involve satellites in low and high or-bits for communications and data transmis-sion, weather reporting, remote surveillance offoreign territory and the high seas, and inter-ception of foreign communications. The cru-cial character of these satellites, especially inproviding information on strategic missileplacements and launches, is such that anyfuture war between superpowers wi l l un-doubtedly include actions in space to destroyor damage enemy satelIites. 73

For these reasons both the United States andthe U.S.S.R. are working to develop antisatel-lite (A-sat) weapons. The Soviets have in thepast tested “killer satellites” capable ofrendezvousing with objects in orbit and ex-ploding on command. ” 75 The United Stateshas not yet tested A-sat weapons in space butis developing a sophisticated orbital intercep-tor designed to be launched from an F-15fighter. ” Neither system is capable of reachinggeosynchronous satelIites w i thou t be ingplaced on larger boosters, but such develop-ment is probably only a matter of time.

The United States and U.S.S.R. have held in-formal talks in the past on limiting or banningA-sat weapons; the most recent such discus-sion took place in June 1979. These talks havebeen complicated by Soviet claims that theSpace ShuttIe is an A-sat system. The talks arecurrently “on hold. ”

An outgrowth of A-sat concern has been therapidly increasing interest, on both sides, inlaser and particle-beam weapons. ” Althoughsome have predicted that such weapons couIdbe deployed within a few years (especiallylasers, whose technology is more advanced

73Clarence Robinson, “Space-Based Systems Stressed,” Avia-tion Week and Space Technology, Mar. 3, 1980, p. 25.

74Soviet Space Programs 1977-1975, VOI 1, staff report for Com-mittee on Aeronautical and Space Sciences, 1976, pp. 424-429.

75Craig Covault, “New Soviet Antisatellite Mission, ” AviationWeek and Space Technology, Apr. 28,1980, p. 20,

“Craig Covault, “Antisatellite Weapon Design Advances, ”Aviation Week and Space Technology, June 16, 1980, pp.243-247

77 See articles in Aviation Week and Space Technology of July28, 1980; also Richard Burt, “Experts Believe Laser WeaponsCould Transform Warfare in 80’s, ” New York Times, Feb. 10,1980, p. 1.

than particle beams), most experts say that, ifat all feasible, they will not be available untilthe end of the decade.

High-energy lasers and particle beams aredesirable because of their speed and accu-racy–light speed for lasers, an appreciablefraction of that for particle beams–makingthem ideal for attacking fast-moving targetssuch as satellites and incoming missiles. Theymay be deployed on naval vessels, antiaircraftpositions, and in space. Space-based directed-energy weapons ‘could theoretically attacksatellites at great distances — up to a thousandmiles — since their beams would not be at-tenuated and dispersed by the atmosphere.Most importantly, they could also be used toengage attacking ICBMs, providing an effec-t ive ABM capabi l i ty that would radical lychange the strategic nuclear balance. Suchuses depend on attaining very accurate aimingand tracking, and extremely high peak-powercapabiIities.

Use of SPS Launchers andConstruction Facilities

The most important military impact of SPSdevelopment would likely be military use ofSPS launchers and construction facilities. Inorder to build an SPS it would be necessary todevelop a new generation of high-capacityr e u s a b l e l i f t v e h i c l e s t o c a r r y m e n a n dmaterials from the ground to low orbit. A sec-ond vehicle, such as an EOTV, would probablybe used for transportation to geosynchronousorbit.

In addition, techniques and devices for con-structing large platforms and working effec-tively in space would have to be developed,along with life support systems and livingquarters for extended stays in orbit.

Improved and cheaper transportation wouldallow the military to fly many more missions,orbiting more and larger satellites and servic-ing these already in place. New constructiontechniques would enable large platforms forcommunications, surveiIlance, and /o r d i -rected-energy uses to be rapidly deployed. The


military would have the further option of fly-ing manned or unmanned missions.

Without SPS, advanced launch-vehicles andconstruction devices may not be built or, atbest, be done so much less quickly. The mili-tary may hence have a strong interest in par-ticipating in their development, as they havewith the Space Shuttle. Whether the militarywould actively support the SPS in order tobenefit from such developments might dependon whether they think SPS funding woulddirect resources away from other military pro-grams.

An ongoing SPS construction project with ahigh volume of traffic into space could pro-vide opportunities for the military to disguiseoperations or incorporate them in normal SPSactivities. Such a possibility would likely causeany unilateral SPS project to be closely moni-tored by foreign observers.

The most s igni f icant use of a f leet ofmilitary-capable SPS launchers and crewswould be in providing a “break-out” capabilitywhereby, in time of crisis, large numbers ofcommunications and surveillance satellites,antisatellite weapons, or directed-energy plat-forms could be placed in orbit on short notice.This would be similar to the way a nationalmerchant shipping or air cargo fleet is viewedas a military asset, and often supported inpeacetime because of its strategic signifi-cance. Fear of such uses might be a spur to thedevelopment of antilauncher weapons, analo-gous to attack submarines or merchant raiders.

Military Uses of SPS

Direct Use of SPS

The energy transmission beams of the SPScould have direct military uses. A microwavesystem in geosynchronous orbit would notgenerate a beam intense enough to causedirect damage to people or installations; itmight be enough to cause minor irritation orpanic if used against populated areas. An in-tense microwave beam might be used to inter-fere with short-wave communications over a

broad area (see ch. 5, Electromagnetic Com-patibility).

Certain laser designs would be sufficientlypowerful and focused to cause some immedi-ate damage to people and structures, butwould not be optimally designed for weapons-use. An SPS would use a continuous laserrather than the high peak-power pulsed lasersneeded for military missions. For such uses, in-creased focusing of the beam would be re-quired, a s w e l l a s a p p r o p r i a t e t r a c k i n gmechanisms. If so equipped, a laser SPS couldbe used directly against satellites and ICBMs,and also against targets on the ground such asships, planes, and oil refineries. Such useswould be greatly facilitated if a laser SPS wereplaced in low orbit, with energy relayed to theground via geosynchronous mirrors. Since asun-synchronous SPS in low-Earth orbit wouldof necessity pass directly over many differentcountries (including the Soviet Union), it couldbe seen as potentially more threatening than ageosynchronous satellite that remains fixedabove one spot. A geosynchronous laser mighthave difficulty tracking low-flying ICBMs andsatellites, due to its position 35,800 km fromthe target.

Since the key requirement for directed-energy weapons is a large power supply, anySPS that generates electricity directly [i.e., anydesign except the mirror-system) can be usedto power such weapons. These weapons couldbe built into the SPS platform or placed at adistance in lower orbits and supplied by lasersfrom the SPS. The question is whether rela-tively small directed-energy weapons can bedesigned with autonomous power supplies,perhaps from nuclear reactors. Since weaponsused against ICBMs must be capable of firing alarge number of very rapid bursts in order toengage a fleet of 1,000 or more missiles, it maybe that SPS power, if available, would be themost efficient and economical way to supplyfuture laser or particle-beam platforms.

Direct use of the SPS in this way would ofcourse make attack in time of war inevitable.Extensive defensive armament would have to

Ch. 7—The International Implications of Solar Power Satellites • 173

be built in; the offensive weaponry could alsobe used to defend against missile attacks.

Any testing, deployment, or use of directed-energy weapons in space is presently prohib-ited by the 1972 ABM Treaty and other spacetreaties. A proposed SPS would probably be atopic of future arms control negotiations toclarify and limit its military implications (seediscussion on pp. 156-1 57).

Indirect Military Uses

In addition to these direct uses, a laser SPScould be used to supply power to militaryunits, providing increased mobility to groundforces that could dispense with bulky fuel sup-plies in remote and roadless areas. Given ade-quate tracking capability it might even be pos-sible to supply mobile units such as ships,planes, or other satel l i tes equipped withthermoelectric converters, increasing theirrange and allowing them to carry more arma-ments or cargo. 78

A geosynchronous SPS is at an advanta-geous position for numerous communicationsand posit ioning uses, mi l i tary as wel l ascivilian. Its large size would make it easy toattach equipment to it; the military’s need forredundancy makes it convenient to use allavailable platforms, as does future crowdingof geosynchronous positions. Operation of amicrowave SPS, however, could interfere withcommunications uses unless switched off.

SPS’s power and position might make itsuitable for electronic warfare uses, such asjamming enemy command-and-control links.This would require the addition of specializedequipment.

The mirror designs use reflected sunlightrather than energy transmission beams. How-ever, it has been suggested that the reflectedlight could be used for weather modificationor for nighttime battlefield illumination. The

“See Michael Ozeroff, SPS Military Implications, DOE/NASAreport, October 1978, pp. 13-1 6; also A Hertz berg, K Sun, andW. Jones, “Laser Aircraft,” Astronautics and Aeronautics, March1979, p. 41,

energy levels are not high enough, in currentdesigns, to change weather patterns signifi-cantly (see ch. 8, Environment). Such use wouldbe prohibited by the 1980 “Convention on theProhibition of Military or any Other HostileUse of Environmental Techniques.”

Nighttime illumination could be significant,especially in cases of guerrilla warfare or ur-ban terrorism where attacking forces rely ondarkness and surprise as equalizers. However,fragile Solares mirrors could probably not beadjusted quickly enough to deal with suddenmilitary developments; rapid deployment ofmirrors by the military for specific uses wouldprobably be more effective.

Ownership and Control

Any of the military uses discussed clearly de-pend on who owns, operates, and builds theSPS system. If SPSs are unilaterally owned bynational governments, their military use is farmore likely than if run by private enterprise orby a multilateral consortium. Fears of militaryinvolvement could be an incentive to estab-lishing a multinational regime to operate orregulate SPSs, and to prohibiting militarily ef-fective SPS designs.

A key question would be who has effectivecontrol over SPSs in a time of crisis. If a privateSPS consortium, having its own launchers andcrews, has a monopoly on SPS control andexpertise, then governments might be hard-pressed to take over SPSs on their own. Alimited defensive capability would help tod e t e r a n y national takeovers. However,governments m i g h t s t i p u l a t e t h a t i n a nemergency they be allowed to commandeerSPSs for defense purposes.

A nongovernmental owner can be expectedto resist any attempts to use SPSs for militaryfunctions rather than supplying electricity tocommercial users. The threat of Iawsuits ordiplomatic protests at electricity interruptionscaused by military preemption might help todeter such actions.

174 ● - Solar Power Satellites

FOREIGN

Interest in SPS has been expressed outside ofthe United States, especially in Europe but alsoin Japan, the Soviet Union, and some develop-ing countries.

●

●

●

●

Europe

The first significant European study of SPSwas done in 1975 by a German firm undercontract from West Germany’s space re-search organization.

In England, the Department of Industryfunded a study, completed in early 1979,tha t l ed to a fu r ther e f fo r t by Br i t i shAerospace to investigate the implications ofSPS for British industry. ”

In France, the work of Claverie and Dupason global demand for SPS has already beenmentioned.

The ESA began SPS assessments in 1977,publishing a-number of papers in the ESAJournal of 1978. Ruth and Westphal per-formed a study in 1979,80 which examinedoffshore sites for rectenna placement, and in1980 a major report on ground receiving sta-tions was published by Hydronamic B.V. ofthe Netherlands.81 In 1978, Roy Gibson, thendirector of ESA, said ESA was “intensely in-terested” in SPS,82 and ESA has supported agroup within the IAF for SPS investigation.In June 1980, an International Symposiumon SPS was held at Toulouse, France, withrepresentatives from many European coun-tries and agencies.83

In general, the European studies have fo-cused on the European requirements for possi-ble contributions to an SPS system. Little

“K. K, Reinhartz, “An Overview of European SPS Activities,”in Firra/ Proceedings of the SPS Program Review, U.S. Departmentof Energy, July 1980, pp. 78-88.

80J. Ruth and W. Westphal, “Study on European Aspects ofSPS,” ESA report No CP(P) 1266.

“A. R. Bresters, “Study on Infrastructure Considerations forMicrowave Energy G round Receiving Station,” Hydronamic Proj-ect, p, 495, November 1980

‘*In Jerry Grey, “The Internationalization of Space, ” Astro-nautics and Aeronautics, February 1979, p 76

83 See Peter Glaser, “Highlights of the International Sym-posium on Solar Power Satellites,” July 1980,

INTEREST

detailed work on the system proper has beendone outside of designs to reduce the size ofrectennas; European participants have reliedon U.S. projects for technical information.Suspension of NASA/ DOE research efforts dueto lack of fiscal year 1982 funding will have anadverse effect on foreign studies and has led togreat disappointment among foreign SPS ex-perts. 84 A major difference between U.S. andEuropean efforts is that while in the UnitedStates SPS has attracted interest from energyexperts and the DOE, European studies havebeen the exclusive province of organizationsinvolved in space research .85

Soviet Union

The Soviets have initiated no major knownstudies of SPS, though there have been un-verified claims of a Soviet SPS project. It is im-possible to tell with certainty what the degreeof interest or expertise is; U.S. experts feel theSoviets are relying on Western reports and arefar from developing the launchers, microwavetransmission expertise, and advanced solarcells necessary to consider an SPS. 86 R e c e n tsigns of interest include a paper ent i t led“Satellite Power Stations” published by scien-tists from M.V. Lomonosov State University,Moscow in December 1977.8788 At the 30thCongress of the IAF in Munich, September1979, the Solar Power Bulletin reported that:“Although the Soviets were reluctant to dis-close their level of commitment to a solarpower satellite program, Chief CosmonautBeregovoy commented ‘ that i f the UnitedStates puts up an SPS first, we will con-gratulate you, and if ours goes up first, we willexpect congratulations from you’. ”89

“Conversation with Jerry Grey, of the Al AA, Oct. 15,1980.“K K Relnhartz, op cit., p 80““Conversations with James Oberg, Johnson Space Center,

and Charle\ Sheldon I I, Congressional Research Service, Septem-ber 1980

“ 5ovlet fpace Programs 1971-/975, VOI 1, staff report, Libraryof ( ongres~, 1976, p 529

““See statement of Peter Claser In House Hearings on SPS, 96thCong , March 1979, p 218

““5pace \o/ar Power Bu//etin, Sunsat Energy Council, February

1980, p 1


Japan

The Japanese have expressed interest andfunded studies within the National Space ’De-velopment Agency, though no permanent of-fice for SPS exists. Japanese interest in spaceexploration and industrialization is strong andincludes plans for several new ser ies ofLaunchers. go

Third World

Information about SPS has been spread tothe Third World by discussions at COPUOS

and by sessions on SPS at international con-ferences such as those of the IAF. Reaction hasgenerally been cautiously optimistic. At the In-ternational Symposium in Toulouse, Dr. Mayurof India’s Futurology Commission claimed:“There is no conflict between small scaletechnologies and the SPS.” Dr. Chatel, formerChief of the UN’s Office of Science & Tech-nology, proposed an international workingparty to coordinate national programs and per-form assessments. ” The SPS has been placedon the agenda of the upcoming U.N. energyconference in Nairobi in the summer of 1981.

‘“James Harford, “Japan Showcases Crowing Space Prowess,”Astronautics and Aeronautics, December 1980, pp. 120-125. ‘ l Glaser, op c i t

It is crucialprojections as

STUDY RECOMMENDATIONS

to continue updating long-term development and foreign military space pro-new information becomes avail- grams, and arms-control negotiations.

able about developments in the space andenergy fields. Close attention should be paidto: 1 ) future global electricity demand undervarious scenarios and on a detailed regionalbasis; 2) evaluation of the impact that possibleexternal events —wars, oiI embargoes, wide-spread famine— couId have on U.S. and Euro-pean energy needs; 3) the feasibility of aunilateral SPS System given a global market,including estimates of profitabiIity; 4) monitor-ing of Law of the Sea negotiations and the re-sulting international regime with special atten-tion to the implications for the Moon Treaty

U.S. energy and space experts often tend topay little attention to the foreign implicationsof their programs. Since SPS is a system thatmay make sense globally but not domesticalIy,neglect of the international dimension couldlead to an unjustified foregoing of SPS devel-opment. In making plans for future R&D pro-grams, attention should be paid to involvingand informing potential partners as well as toconsidering the ways in which a global systemmight differ, technologicalIy and institution-alIy, from a domestic one.

and other space agreements; and 5) weapons

Chapter 8


ContentsPage

Introduction . . . . . . . . . . . . . . .. ....179

Environment. . . . . . . . . . . . . . . . . . . .. ...182Power Transmission Effects on the

A t m o s p h e r e a n d W e a t h e r . . . 1 8 2Atmosphere . . . . . . 1 8 3S p a c e V e h i c l e E f f e c t s . . . . . . . 1 8 7E lec t romagnet ic In te r fe rence . . . . . . . 190T e r r e s t r i a l A c t i v i t i e s . . . . . . . . . 1 9 6Receiver Structure: Weather

Modification . . . . . . . . .. ....205

Health and Ecology . . . . . . . . ........207T e r r e s t r i a l E f f e c t s . . . . . . . . . . . . . 2 0 7

ionizing and Nonionizing RadiationDefined. . . . . . . . . . . . . . ........209

Space Environment. . . .. ....221

LIST OF TABLES

Table No. Page

28.

29.

303132

333435.36.37.

38.

39,40.

41.

Summary of SPS EnvironmentalImpacts . . . . . . . . . . . . . . . .....180Major SPS EnvironmentalUncertainties . . . . . . . . . ....,.182Power Transmission Impacts. . . . . . . .184SPS Space Transportation Vehicles. ...188Exhaust Products of SPS SpaceTranspor ta t ion Veh ic les . . . . . . . . . 189S p a c e V e h i c l e I m p a c t s , . . . . . . . 1 8 9Summary of Electromagnetic Effects. .192SPS Systems Land Use. . . . . . ......198Summary of Land Requirements. .. ...199Summary of Environmental Impacts ofRectenna Construction and Operationat a Specific Study Site . . . . . 203Summary of Materials AssessmentResults . . . . . . . . . . . . . . . . . . ......205Annual Environmental Effects of SPS. .206Terrestrial Health and EcologicalImpacts. . . . . . . . . . . . . . ......208Characteristics of Exposure toReference System Microwaves . . . . . . .211

4243

4445

46

47

4849

M i c r o w a v e E x p o s u r e L i m i t s .Research Needs To Help ReduceUncertainties Concerning PublicHealth Effects Associated WithExposure to SPS Microwaves Power

D e n s i t i e s a n d F r e q u e n c y . .S P S D e v e l o p m e n t . . . .Estimated Sound Levels of HLLVlaunch Noise . . .

. 2 1 2

. 2 1 3

. 2 1 7

. 2 2 0Representative Noise Levels Due toVarious Sources . . . . . . . . .220Community Reaction to HLLV LaunchNoise~ . . . . . . . . . . . . . . . .. .221Sonic Boom Summary. . .221Types of Radiation Found in theDifferent SPS Orbits . . . . . . . . . . . . .223

LIST OF FIGURES

30.31.

32.3 3.

34.

35.36.37.

38.

39.

40.

41.42.43.

Regions of the Atmosphere. . . . .183Examples of SPS MicrowaveTransmission Effects on theIonosphere and TelecommunicationSystems. . . . . . . . . . . . . . .184Summary of SPS Atmospheric Effects, .188Receptor Site Protection Radius as aFunction of the Perimeter laser Power-Density Level. . , . . . . . . . . .197Microwave Power Density at Rectennaas a Function of Distance FromBoresight. . . . . . , . . . , . . .197Rettenna/Washington, D.C. Overlay. . .198Offshore Summary Map . . . . . . . . .200Satellite Power System — SocietalAssessment . . . . . . . . . . . . . . .201Regional Generation andRectenna Allocations . . . . . .202The Electromagnetic-Photon Spectrum, 209SPS Microwave Power-DensityCharacteristics at a Rectenna Site. .. ..211Comparison of Exposure Standards . .. 216Program Funding. . . . . . . . . . . .216Factors Pertinent to Space WorkerHealth and Safety . . . . . . . . . . . . . . . .. 222

Chapter 8


INTRODUCTIONAs a large-scale energy system operating in

both the space and terrestrial environments,the solar power satellite (SPS) is unique. Andbecause it is a new concept, our understandingand experience of a number of the environ-mental impacts associated with SPS are lim-ited. The great uncertainties surrounding theseeffects make comparisons between SPS andother energy technologies especially difficult.While one advantage of SPS is that it wouldavoid many of the environmental risks typi-cally associated with conventional energy op-tions such as coal and nuclear, it also wouldgenerate uncommon environmental effectsthat presently cannot be quantified or com-pared to those of other powerplants. The largeuncertainties also tend to provoke public de-bate. In light of past controversies over thesiting of powerplants, transmission Iines andother facilities, it is clear that environmentalissues could play a key role in public consid-eration of SPS (see ch. 9).

This chapter will outline the environmentaland health impacts of SPS that are currentlythought to be most important. It will identifyresearch needs and highlight areas of con-troversy. As with other aspects of SPS, the en-vironmental effects have been evaluated mostfully for the reference system. Some of thisdata is also applicable to the other SPS tech-nical options, di f fer ing only in extent ordegree, but information on the full range oftheir environmental effects is limited.

At the current stage of development, SPS en-vironmental studies can play an important rolein determinin g concept feasibility, technicaldesign, and cost. For example, bioeffects re-search might influence the choice of frequen-cy which, in turn, couId determine hardwaredesign and Iand use. Thus, many of the effectscurrently identified might be minimized by ap-propriate choices of design. However, it is alsopossible that one or more risks might be iden-tified in the development process that couldnot be reduced to an acceptable level without

jeopardizing the economic or technical viabili-ty of the SPS concept.

The SPS environmental effects and the costof reducing them must be viewed in the con-text of energy technologies, energy needs,other space activities, and the incrementaleffect on human health and the environment.Preliminary comparative assessments indicatethat, in general, those health and environ-mental impacts of the reference system SPSthat can presently be quantified would prob-ably be no more severe than for other large-sc aIe electricity generating technologiesa l t h o u g h t h e u n c e r t a i n t i e s f o r S P S a r ehigh). 1 2 3 4 I n fact, when compared to coal,SPS would be an order of magnitude cleaner(see app, D). However, if an SPS program ispursued, further comparative analysis betweenenergy options would be required as more islearned about the unquantifiable impacts thatcould not be incorporated in the presentstudies A good portion of this chapter dis-cusses these latter effects for SPS.

The discussion in this chapter relies heavilyon the data and analysis generated by the De-partment of Energy (DOE) 5 and the NationalAcademy of Sciences (NAS). 6 7 The reader is

——-. ——11 j Ha begger , J R Gasper, and C D Brown, Hea/th and Safe-

tv Pre/lrnlrtary Cor-nparatlve Assessment of the Sate//ite Power$vstem / SPS) and Other Energy Alternatives, DOE/NASA reportNo DO I IF R-0053, April 1980

‘CI t Newsom and T D Wolsko, Pre/irnfnary Compara t i ve As-SCJS smen t o t Land Use for Satellite Power Systems and A Iternatl ‘.teF /ectrlc t nergy Technologies, DOE/NASA repor t No[ )OE I R-0058, April 1980

‘D A Kellermeyer, C/imate and Energy: A Comparative Assess-ment of the SPS and Other Energy A /ternatives, DOE/NASA reportNo DO} F R-0500, January 1980

‘F P Levine, M J Senew, and R R Clr[llo, C o m p a r a t i v eAssessment of Environmental Welfare Issues Associated With the\ate//lte Power System and Alternative Technologies, DOE/NASA

repor t ho [)OE/E R-0055, Apr i l 1980

5Envlronmenta/ Assessment for the Sate//ite Power System Con-cept Development and Evacuation Program, DOE/NASA report

No DOt /E R-0069, August 1980

“Comrnlttee o n S a t e l l i t e P o w e r S y s t e m s , N a t i o n a l R e s e a r c h

( ounc!l O p e n C o m m i t t e e M e e t i n g s J a n 3 1 - F e b 1 , 1 9 8 0 , A p r

910, 1980, j U Iy 1-2, 1980, Oct 1-2, 1980

‘(’ H l>odge (rapporteur), Workshop on Mechanisms Under/y-

179


referred to the DOE documents for more de-tailed discussions. While those studies havenot identified any environmental reasons notto continue with SPS development, it is veryevident that much more study and research

(continued from p. 179)

Ing Effects of Long-Term, Low-Level, 2450 MHY Radiation onPeep /e , organized by the National Re\ear( h (-ouncil, C o m m i t t e e

o n Satel I Ite P o w e r S y s t e m s , E nvlrontmental Studms floard, N a

tlonal Academy of Sciences, July 17-17, 1980

would be required before decisions could bemade regarding the environmental viability ofSPS. What is not clear is how long it might takebefore our confidence in the resolution ofsome environmental impacts such as micro-wave bioeffects would be high enough tomake development or deployment decisions.

As table 28 illustrates, there is a great diver-sity of environmental and health impacts. Of

Table 28.—Summary of SPS Environmental Impacts

System componentcharacteristics Environmental impact

Power transmissionMicrowave — blonospheric heating could

disrupt telecommunications.Maximum tolerable powerdensity is not knownEffects in the upperionosphere are not known

—Tropospheric heating couldresult in minor weathermod if i cat ion

— bEcosystem: microwave bio-effects (on plants, animals,and airborne biota) largelyunknown; reflected lighteffects unknown

— bpotential interference withsatellite communicant ions,terrestrial communications,radar, radio, and opticalastronomy

Lasers —Tropospheric heating couldmodify weather and spreadthe beam

—Ecosystem: beam mayincinerate birds andvegetation

— bpotential i n t e r f e r e n c ewith optical astronomy,some interference withradio astronomy

Mirrors — bTropospheric heatingcould modify weather

—Ecosystem: effect of 24-hr light on growingcycles of plants and cir-cadian rhythms of animals

— bpotential interferencewith optical astronomy

Public health and safety—

— bEffects of low-levelchronic exposure to micro-waves are unknown

— Psychological effects ofmicrowave beam as weapon

—Adverse esthetic effectson appearance of night sky

Occupatlonal healthand safety

—Higher risk than forpublic; protectiveclothing required forterrestrial worker

—Accidental exposure tohigh-intensity beam inspace potentially severebut no data

—Ocular hazard? —Ocular and safety—Psychological effects of hazard?

laser as weapon arepossible

—Adverse esthetic effectson appearance of nightsky are possible

———Ocular hazard? —Ocular hazard?—Psychological effect of

24-hr sunlight— b Adverse es the t ic e f f e c t s

on appearance of nightsky are possible


Launch and recovery

HLLVPLVCOTV

—Ground cloud might polluteair and water and causepossible weather modi-fication; acid rainprobably negligible

— bWater vapor and other

—Noise (sonic boom) may —bSpace worker’s hazards:exceed EPA guidelines ionizing radiation

—Ground cloud might affect (potentially severe)air quality; acid rain weightlessness, lifeprobably negligible support failure, long

— Accidents-catastrophic stay in space,

Ch. 8—Environment and Health ● 181

Table 28.—Summary of SPS Environmental Impacts—Continued—— —

System component Occupational healthcharacteristics Environmental impact

POTV launch effluents coulddeplete ionosphere andenhance airglow. Result-ant disruption of com-munications and satellitesurveillance potentiallyimportant, but uncertain

— bpossible formation O fnoctiIucent clouds instratosphere and meso-sphere; effects on climateare not known

— bEmission of water vaporcould alter naturalhydrogen cycle; extent andimplications are not well-known

— bEffect of COTV argon ionson magnetosphere andplasmasphere could begreat but unknown

—Depletion of ozone layerby effIuents expected tobe minor but uncertain

—Noise

Terrestrial activitiesMining —Land disturbance

(stripmining, etc.)—Measurable increase of

air and water polIution—Solid waste generation—Strain on production

capacity of galliumarsenide, sapphire, silicon,graphite fiber, tungsten,and mercury

Manufacturing —Measurable increase ofair and water pollution

—Solid wastes

Construct ion —Measurable landdisturbance

—Measurable local increaseof air and water pollution

Receiving antenna — bLand use and siting—major impact

— Waste heat and surfaceroughness could modifyweather

High-voltage — bLand use and siting—transmission lines major impact(not unique to SPS) — bEcosystem: bioeffects of

powerlines uncertain

Public health and safety and safety—explosion near launch construction accidentssite, vehicle crash, toxic psychological stress,materials acceleration

—Terrestrial worker’shazards: noise, trans-portation accidents

—Toxic material exposure —Occupational air and—Measurable increase of water pollution

air and water pollution —Toxic materials exposure— Land-use disturbance —Noise

—Measurable increase of —Toxic materials exposureair and water pollution —Noise

—Solid wastes— Exposure to toxic

materials—

—Measurable land —Noisedisturbance —Measurable local

—Measurable local increase increase of air and waterof air and water pollution pollution

—Accidents——..—bLand use— reduced — Waste heat

property value, esthetics,vulnerability (less landfor solid-state, laseroptions; more for referenceand mirrors)

— bExposure to high light intensitity — bExposure to highEM fields—effects intensity EM fields—uncertain effects uncertain

al mpacts based on sps systems as currently defined and do not account for offshore rece!vers or possible mitigating sYStem rnodificatlonsbResearch priority.



most concern are: 1) the biological effects ofelectromagnetic radiation produced by thepower transmission and distribution systems;2) the atmospheric effects of electromagneticradiation and launch effluents and the re-sulting impacts on telecommunications and airquality; and 3) the land requirements and sitingconsiderations for ground-based receivers. Thegreatest environmental uncertainties are Iistedin table 29.

The first part of the chapter will deal withthe potential environmental impacts resultingfrom the construction and operation of SPSsystems. These and other effects will then beaddressed in the second section as they pertainto human health and ecosystems. Detailed dis-cussion of a number of impacts is found in ap-pendix D.

Table 29.—Major SPS Environmental Uncertainties

Reference and solid-state systems●

●

●

●

Microwave bioeffects -

—Low-level, chronic exposureLaunch effluent effects—Ions in the magnetosphere—Natural hydrogen cycle—Ionospheric depletion—Noctilucent cloudsMicrowave heating of the ionosphereEffects on telecommunicationsLand use

Laser system● Laser bioeffects. Tropospheric heating● Launch effluents• Land use

Mirror system● Weather modification• Land use● Biological and psychological effects of 24-hr light

Systems comparisonsSOLi~~E Of~c;of Technology Assessment

ENVIRONMENT

One of the consequences of constructingand operating an energy system in space is thatthe extent of the environment that is directlyaffected by the system is much broader thanfor Earth-based powerplants. For example,both the transmission of SPS power and the in-jection of launch effluents will directly affectevery layer of the atmosphere. The purpose ofthis section is to discuss the state of knowledgeof the predominant environmental impacts ofSPS, especially those that are fairly unconven-tional and to outline areas where further re-search would be needed. Biological effects,i.e., human health and safety and ecologicalimpacts, are deferred to the second part of thechapter.

The two major environmental concerns atthe present time are: 1 ) the effect on the at-mosphere of the transportation and powertransmission systems; and 2) electromagneticinterference with communications systemsand astronomy.8 With respect to the former,the effluents emitted from the launch vehicles

8Program Assessment Report, Statement of Findings, SatellitePower Systems Concept Development and Evaluation Program,DOE/NASA report No DO E/E R-0085, November 1980

couId deplete portions of the ionosphere, alterthe natural hydrogen cycle and magneto-sphere dynamics and modify weather and airquality near the launch site. The effects of thepower transmission system on the atmospb”are a function of the frequency of theFor the laser and mirror systems, the mo~nificant potential impact is heating ofnear-Earth atmosphere, which might alterweather. If the microwave beam were to altthe ionosphere, i t couId disrupt te lecommu n i cat ions.

In order to understand clearly these and theother more conventional environmental im-pacts described in this chapter, it is worthwhileto review the properties and structure of theatmosphere as illustrated in figure 30 and dis-cussed in box A.

Power Transmission Effects onthe Atmosphere and Weather

Current SPS designs transmit energy to Earthusing microwaves, lasers or reflected light.Since the atmospheric effects of power trans-mission are highly frequency dependent, each


Figure 30.— Regions of the Atmosphere

Solar radiation excites, disassociates and ionizes atmospheric constit-uents. The ionosphere in particular is a region of marked abundance of freeelectrons and ions. The properties of the ionosphere vary with latitude,time of day, season and solar activity. When electromagnetic waves enterthe ionospheric plasma, they will be refracted and slowed down. Depend-ing on the frequency of the incident wave and properties of the ionosphere,the wave can be totally reflected. It is this phenomena that makes manyradio frequency communication systems possible.

100

10

1

Regions of the atmosphere

SOURCE: Program Assessment Report, Statement of Satellite PowerSystems Concept Development and Evaluation Program, DOE/NASAReport, November 1980

of these will be discussed separately. Table 30summarizes the impacts of most concern.

M i c r o w a v e s ’

As the beam from a microwave satell i tetraveled towards Earth, it would heat the at-

mosphere. While attenuation of the micro-wave beam by clouds and rain in the tropo-sphere couldcloud dynamics

cause a slight modification of and precipitation, 9 a b s o r p t i o n

op


Table 30.—Power Transmission Impacts

MicrowavesUpper ionosphere telecommunications effects unknown;experiments and improved theory are neededLower ionosphere impacts are thought to be negligiblefor a number of telecommunications systems; scalinglaws must be verified and effects on telecommunicationsystems operating in the 3 MHz to 20 MHz range must betestedThe maximum power density for which telecommunica-tions effects are insignificant is not known and must bedeterminedTropospheric heating is not thought to be significant

Lasers● Thermal blooming in the troposphere may degrade the

beam● Tropospheric heating may cause increased cloud forma-

tion, turbulence and weather modification● Effects on the mesosphere, stratosphere, and ther-

mosphere and continental cloud distribution and albedoare thought to be inconsequential

Reflected light● Weather modification in vicinity of ground sites is possi-

ble, but unquantified. Photochemistry of the ozone layer is not thought to be af-

fected


of microwave energy is most important in theionosphere. Of particular concern are the ef-fects of ionospheric heating on telecommuni-cation systems that rely on the ionosphere totransmit and reflect radio waves. Changes inthe ionospheric properties due to heating candegrade (or in some cases, enhance) the per-formance of telecommunication systems byabsorbing or scattering the radio signals (seefig. 31). Specifically, these effects could resultin losses, fading, and scintillation of the elec-tromagnetic signals. It is also possible that theSPS pilot beam itself could be affected by theheated ionospheric layers.

In the course of the DOE assessment severalexperiments were conducted to test the extentof heating and the effect on telecommunica-tions in the lower ionosphere. These experi-ments demonstrated that while heating doesoccur the effects are not serious for the tele-

Figure 31 .—Examples of SPS Microwave Transmission Effects on the Ionosphereand Telecommunication Systems

F-region

ion

SOURCE: Prograrn Assessment Report, Statement of Findngs, Satellite Power Systems Concept Development and Evalua-tion Program, DOE/NASA Report, DOE/ER-0085, November 1980


communicat ion systems tested. Some re-searchers have even suggested that the pro-posed power density of 23 mW/cm2 could bedoubled without significant impact to tele-communicat ions in the lower ionosphere.However, more research is needed in order todetermine the power density threshold in thelower ionosphere, and for this the power densi-ty of the existing heating facilities will have tobe increased. Additional study is also requiredto ascertain the effects in the lower ionosphereon telecommunication systems that operate atfrequencies greater than 3 MHz (i.e., 3 to 100MHz) range. In addition the effects of multiplemicrowave beams need to be determined.

Our knowledge of upper ionosphere (F re-gion) heating is less advanced than in the D & Eregions. Few underdense experiments (i. e., thebeam travels through the region as opposed tobeing reflected, which is termed an overdensecondition) to simulate SPS heating have beenattempted. Recent experiments’ 2 suggest thationospheric irregularities can be created whenthe Platteville heater operates in an under-dense mode and that these irregularities in-duce scintillations in very high frequency satel-Iite-to-aircraft and satellite-to-ground trans-mission links. Further work would be required,however, to establish whether scintillationswould occur if SPS heated the upper iono-sphere. Presently, the theoret ical scal ingmodels that would extrapolate these results toSPS conditions in the F-region are very uncer-

IOEnvironmental Assessment for the Satellite Power System –Concept Development and Evaluation Program – Effects of iono-spheric Heating on Telecommunications, DOE/NASA report No

DO E/ ER-10003-Tl , August 1980

1‘W E G o r d o n a n d L M D u n c a n , “ R e v i e w s o f S p a c e S C I-

ence — SPS Impacts on the Upper Atmosphere, ” Astronautics andAeronaut ics, VOI 18, No 7,8, July/August 1980, p 46

‘2 S Basu, A L, Johnson, J A Klobuchar, and C M Rush, “Pre-

l im inary Resu l ts o f Sc in t i l la t ion Measurements Assoc ia ted Wi th

I o n o s p h e r e H e a t i n g a n d P o s s i b l e I m p l i c a t i o n s f o r t h e S o l a r

Power Satell ite, ” Ceophysica/ Research Let ters, VOI 7, No 8,August 1980, pp 609-612

tain. In order to test these theories, the ground-based heating facilities will have to be up-graded

In sum, it appears that effects on telecom-munications in the lower ionosphere wouldprobably be negligible, but more study of theupper ionosphere effects is needed. By makingthe heating facilities more powerful, the fol-lowing research can be conducted:

●

●

Lower ionosphere: verify scaling theory;and test additional telecommunicationsystems (e. g., VHF, UHF, satel l i te- to-ground)

Upper ionosphere: refine and verify F-region scaling laws and ionospheric phys-ics and then test effects on representativetelecommunicat ions systems for SPSequivalent heating.

Lasers

The most significant potential environmen-tal effects associated with the SPS laser systemappear to be local meteorological changes andbeam spreading due to tropospheric heating.

Tropospheric heating would result fromenergy absorption by aerosols and moleculesand from the dissipation of receptor wasteheat. Attenuation by scattering from mole-cules and by absorption and scattering fromaerosols would be greatest for short wave-lengths. Thus scattering would be only signifi-cant for visible wavelength lasers, while aero-sol effects become important to infrared lasersonly under hazy or overcast conditions.

The absorption of laser energy would lead toa process called “thermal blooming, ” in whicha density gradient acts as a gaseous lens that

83-316 0 - 81 - 13


can spread, distort or bend the laser beam.13

The severity of the thermal blooming would bea function of several parameters, including thefrequency and intensity of the laser, the windvelocity, atmospheric density, absorption andaltitude. Laser wavelengths that have high at-mospheric transmittance would be less likelyto suffer f rom thermal blooming. Thermalblooming could also degrade and spread thebeam. It is clear that if spreading did occur itwould be less critical for the space-to-EarthSPS beam than for Earth-to-space transmission(i.e., laser pilot beam) that would be deflectedearlier in its path.

Tropospheric heating would be likely to in-duce meteorological alterations. It is unlikelythat global climate changes could result sincethe absorption of laser energy would be lessthan the typical natural variations of the at-mosphere; it would take the deployment of200,000 to 400,000 laser systems before theglobal climate might be affected. ” The poten-tial local weather effects include changes inwind patterns, evaporat ion of sect ions ofground fogs and clouds and elevated tempera-tures. None of these effects are expected to ex-ceed those associated with conventional nu-clear powerplants o f c o m p a r a b l e p o w e rrating. ’5 The most significant potential impactwould be updrafts above the receptor site,which might induce cloud formations (a prob-lem for the beam) and severe turbulence in thelower troposphere. Increased turbulence is notnecessarily an adverse effect; the upward con-vective air movement would promote verticalmixing and the dispersal of waste heat. 16 How-ever, the turbulence could present a hazard toaircraft that flew in the affected region. Forthis and other reasons, it has been suggestedthat aircraft be restricted from flying throughtransmission areas. 7

The laser beam would be capable of boringholes through thin clouds and fog by evaporat-

13R E Beverly, Sate//ite Power Systems (SPS) Laser Studies,Technical Report–Laser Environmental Impact Study, VOI 1,Rockwel l In ternat iona l repor t No SSD 8 0 - 0 1 1 9 - 1

“ I b i d

‘Slbld“[bid“Ibid.

ing the water from aerosol droplets. After pass-ing through the beam, the cloud fog wouldrecondense. Portions of noctilucent clouds inthe mesosphere might also be vaporized. Thepossible environmental consequences, such asalteration of the continental cloud distributionor albedo, would be slight but research wouldstiII be needed.

Preliminary analysis indicates that the po-tential impacts in other atmospheric regionswould be negligible. 18 In the stratosphere,ozone would not be affected for wavelengthsgreater than 1 micron. Possible perturbationsof the plasma chemistry by the laser beam inthe mesosphere and thermosphere are be-lieved to be small and inconsequential, sincethe interactions would be confined to the laserbeam volume; ionospheric heating would alsobe negligible. ” However, research would beneeded in order to validate this conclusion.

In the near term, environmental studiescould concentrate on the following areas:

Ž

●

Thermal blooming — increase theoreticalunderstanding and refine models; in-vestigate enhancement of thermal bloom-ing by clouds; study transmission and ther-mal blooming as a function of laser fre-quency, time of year, and receptor al-titude and location.Induced clouds–study the extent andconsequences of induced clouding.

Reflected Light

The mirror system would reflect about 0.8k W / m2 of light to Earth, somewhat less thanthe illumination due to the Sun.20 The primaryatmospheric effect of this additional lightwould be tropospheric heating. Coupled withthe sensible heat release at the energy con-version site, the weather might be measurablymodified as convection, cloud formation, and

—— .—‘“t Li Wa Ibrlclge, La$er %te//lte f>ower ~y$tem~, A r g o n n e N a -

t Iona I I aboi-atory, AN L E S-92, January 1980

‘“llt’k erly, op clt

“K W’ BI I I m a n , W P G Ilbreatll, a n d S W B o w e n , “ S o l a r

I nergy 1 c onornlcs Orbltlng Reflector~ t o r W o r l d E n e r g y , ” In

I+o;t h’1~ ,]nd $tI// Beautlfu/ A4acro-Fngineerlng R e v i s i t e d , F P

D a v i d s o n , et al (eds ) (Bou lder , Colo A m e r i c a n A$soclatlon for

I he A(ivancement o f Sc ience, We>tvlew Pre\$, 1980), PP 2~3-3 J9


rainfall above the site are increased. While noassessment has been made of the magnitude orconsequences of this potential impact, theweather effects of other “heat islands” of thesame scale, such as New York City that re-leases about 0.6 kW/m2 of heat, can be usedfor comparison. ” Weather impacts on a globalscale are not anticipated since the mirrorsystem would add less than 0.015 percent tothe normal solar heat input. 22 Large-scale com-putations on weather models applicable to themirror system size are needed to quantify theeffects for different locations. Additionally,the heating effects of the orbiting refiectorsystem could be simulated on the ground,using solar heated ponds or other meanswithout the need for a demonstration satelliteand hence at a relatively low cost and at anearly time. 23

Once the potent ial weather impacts aremore clearly understood, the system designand economics could be reevaluated to ac-commodate possible environmental concerns.For example, one might redesign the system toreflect less Iight to Earth or use heat dispersiondevices on the ground and in space to rejectthe heat into areas that would have the mini-mal impact. Dichroic mirrors in space for ex-ample, could selectively reflect to Earth onlythose wavelength bands that would be con-verted with highest efficiency at the receivingsite. It may also be found that the weathermodification induced by the mirror systemheat is actually beneficial to the receiving re-gion by preventing cloud impingement oversite.

In addition to tropospheric heating, otherpossible environmental impacts have beensuggested. The mirror system beam might per-turb the photochemistry of the atmosphere,particularly the ozone layer. However, pre-liminary analysis indicates that the effectwould be negligible.24 Further study is neededto confirm this finding and to investigate the

‘ 1 Kenneth f31 I I man, E PR 1, Private ( ommun I( atlon

“K BII I man , W P G Ilbreath, S W Howen, “So la r t ner,gy Re-

vlslted W Ith Orbit Ing Ref Iector$, N A 5A, A me\

‘‘f311 I man, private commun Icatlon

“BII I man, G Ilbreath, and Bowen, So lar Energy F conom I( ~, ‘

Op (-It

potential photochemistry effects if dichroicmirrors were used in space. 25

More detailed study is required before rea-sonable comparisons can be made betweenthe mirror system and the other SPS technicaloptions. Research priorities include:

●

●

●

weather modeling and large-scale com-putations applicable to large mirror sys-tem size,the effects of dichroic mirrors on the sys-tem’s environmental impacts, andpossible ground-based experiments tosimulate mirror system heating.

Space Vehicle Effects*

There are two major environmental effectsassociated with the space transportation seg-ment of SPS: the injection of rocket exhaustproducts into the atmosphere (see fig. 32) andnoise generated at the launch site (see Healthand Ecology). The severity of these impactswould depend on the size and frequency oflaunches, as well as the composition of rocketfuels and fIight trajectory.

Assessment of the potential SPS effects onthe atmosphere is hampered by the unprece-dented scale of SPS transportation require-ments as well as an incomplete understandingof the atmosphere. The reference design, forexample, requires that a heavy lift launch vehi-cle (HLLV), five times larger than the Saturn V,be flown one to two times per day for 30years.”) The other reference system space vehi-cles and launch schedules are shown in tables31 and 32.

The effects of SPS exhaust products on theatmosphere are also uncertain because muchof our theory and experience with the effectsof launch effluents stem from the space shut-tle, which uses solid-fuel boosters. Since theSPS HLLV would be fueled with liquid propel-lants, the composition and distribution of the

- ‘ 1+1 I In)(i n, private ( ommu n 1( at Ion

J(’t’ ,1 1)1) [ ) tor (l(~ta I Is

‘ / II L ~r(]nm(~n(,]/ ! >~c~~ment for the $ate//Itc P o w e r ‘iy~tem( ( )n( f>p( 1 )fII f]/oprrrcnt ,] nc] F ~ .I /[Ia (Ion Prcj#r,]m, [JOE E R-()()()!),A[lgu\t 1‘)80


Figure 32.—Summary of SPS Atmospheric Effects

LEO to GEOOrbit transferpeople carrier> chemicalscargo carrier > ions

Alteration ofsatellite environment

Alteration of plasmasphericand magnetosphericpopulations and dynamics

Ionospheric depletion

o

SOURCE: Environmental Assessment for the Satellite Power System ConceptDevelopment and Evaluation Program, DOEI/R-0069, August 1980.

reference system launch effluents would differfrom that of the shuttle.

The major space vehicle impacts of the ref-erence system are identified in table 33. Pres-ently, the greatest uncertainties are associatedwith four potential effects 27 (treated in moredetail in app. D):

● I n the magnetosphere, the emission ofions from COTVS and POTVS would sub-stantially increase the ambient concen-trations of these particles. Because of ourpoor understanding of the complex dy-namics and composition of this region,potential impacts can be identified, butthe likelihood and severity of these ef-fects are highly uncertain. Possible effectsinclude enhancement of Van AlIen belt ra-diation and changes in magnetosphericand plasm aspheric dynamics that couldperturb ionospheric electr ic i ty , t ropo-spheric weather, and satellitecat ions.

— — —‘Pro~r,]m As~e\\ment Report, $tatement o

c o m m u n i -

F~ndin,q\, op clt

Table 31 .—SPS Space Transportation Vehicles

Launches b Operating Main exhaustName Function Propellants per year altitude (km) products c

Heavy-lift Transport CH4/O2 (stage 1) 375 0-57 C 02, H20launch vehicle material H2/02 (stage 2) 375 57-120 H 20, H2

(HLLV) between Earth H2/O 2 (circular- 375 450-500 H 20, H2

and LEO ization/deorbit)Personnel Transport Details not 30 0-500 C 2, H20, H2

launch vehicle personnel available(PLV) between Earth (probably same

and LEO as HLLV)Cargo orbit- Transport Argontransfer vehicle materials H 2/ 02

(COTV) between LEOand GEO

Personnel orbit- Transport H 2/ 02

transfer vehicle personnel(POTV) between LEO

and GEO

30

12

500-35,800

500-35,800

Ar+ plasmaH2O, H2

H2O, H2

%HJOZ: liquid methanelliquid oxygen HJOZ: liquid hydrogenlliquid oxygen..

bAssuming construction of two (silicon option) 5-Gw satelliteslyear.CCOZ: carbon dioxide HzO: water H,: hydrogen Ar + : argon ion.

SOURCE: Environmental Assessment for the Satellite Power System Concept Development and Evaluation Program, DOE/ER-0069, August 1980,

Ch. 8—Environment and Health Ž 189

Table 32.—Exhaust Products of SPS Space Transportation Vehiclesa

AltitudeAtmospheric rangeregion (km) Source b

Troposphere 0-0.50.5-13

Stratosphere 13-50Mesosphere 50-80Thermosphere 80-125

LEOd

LEOExosphere GEOd

477-GE0

HLLV, PLVHLLV, PLVHLLV, PLVHLLV, PLVHLLV, PLVHLLV, PLV

POTVPOTV

COTVe

Totalmass

(t)c

650-28503027

7582031

33460153985

Mass of specific emission products (t)

C0 2 co H 2 O H2 Ar +

260 117 260 13 —1140 513 1140 57 —1210 546 1210 61 —

199 90 450 19 —— — 1960 71 —— . 443 1 —— — 443 11 —— — 147 6 —— — 0 0 985 f

aMass emissions per flight.bpLV emissions would be ~hemi~all~ similar t. those of the l+LLV, but are not Otherwise determined at ttlls time. The numbers shown are emissions Of the HLLV OIIiyct = metric ton = 1000 ‘g.dLow earth orbit (LEO) is at 477 km; geosynchronous earth orbit (GEO) is at 35,800 kmeln addition t. mass emissions, the argon plasma en~lnes of the COTV would inject a significant amount of energy into this altitude range. Also ar90tl pla.sllla el19illeS

would be used for satellite attitude control and stationkeeping control at GEO; these em Isslons are unknown at present and have not been included.fAr+ mass for the silicon Photovoltalc cell option For the gallium aluminum arsenide Opt!on, the Ar+ mass Would be 212 t.

SOURCE: Environmental Assessment for the Satell)te Power System Concept Development and Evaluation Program, DOEIER-0069, August 1980.

Table 33.—Space Vehicle Impacts

Troposphere● Ground cloud nuclei and heat could have a measurable

effect on weather● N OX emissions are small compared to typical powerplant,

but in conjunction with ambient concentration could ex-ceed projected EPA standards

Stratosphere and Mesosphere●

aEmission of water vapor may cause noctilucent cloudsin the mesosphere; climatic effects would probably besmall, but uncertain

. aWater and N OX are not expected to significantly alterozone, but uncertainties remain

Ionosphere●

●

●

aFormation of large ionospheric hole in F-region fromwater and other effluents should not adversely affect HFtelecommunication signals over distances significantlylarger than the ionospheric depletion, impacts on othertelecommunications systems are not known; morestudies are needed; long-term depletion around launchtrajectory possibleaD&E region effects are poorly understood; impacts ontelecommunications from depletion of the ionosphereare possiblePossibility of enhanced airglow and Perturbation of VanAllen belts, but likelihood is-unknown’

Thermosphere and Exosphere●

aLarge increase in water content might alter the naturalhydrogen cycle and affect the dynamics of the region

Plasmasphere and Magnetosphere●

aArgon ions and hydrogen atoms might enhance VanAllen belt radiation, generate ionospheric electric cur-rents that would interfere with public utilities, modifyauroral response to solar activity and affect weather andsatellite communications, but probability and severity areunknown

● The effects of the satellite structures are thought to benegligible or easily remedied

aResearch priorities.


●

●

●

The injection of water vapor in the upperatmosphere would significantly increasethe water content relative to natural lev-els. One possible consequence is an in-crease in the upward flux of hydrogenatoms through the thermosphere. If anaccumulation of hydrogen results, thedynamics of the thermosphere and ex-osphere could be affected. Satellite dragcould also be increased. Models of thenatural hydrogen cycle are needed toquantify and simulate the effects of SPSon global scale.

The injection of rocket exhaust, particu-larly water vapor, into the ionospherecould lead to the depletion of large areasof the ionosphere. These “ionosphericholes” could degrade telecommunicationsystems. While the uncertaint ies aregreatest for the lower ionosphere, ex-periments are needed to test more ade-quately telecommunications impacts andto improve the theoretical understandingof chemica l -e Iec t r i ca I interact ionsthroughout the ionosphere.

Another consequence of increasing theconcentration of water in the upper at-mosphere might be the formation of noc-tilucent clouds in the mesosphere. Whileglobal climatic effects of these clouds arethought unlikely, uncertainties remain,especially with respect to the persistence


of the clouds as a function of tempera-ture.

The transportation system for other SPS op-tions could be substantially different from thatfor the reference system. For example, the mir-ror system and the bulk of the laser systemsatellites operate in low-Earth orbit (LEO). Themagnetospheric effects associated with trans-porting materials to geostationary orbit (CEO)would therefore not be a problem for thesesystems. Environmental impacts are also deter-mined by the frequency of launches, whichdepends on the size of the vehicle, and thetotal mass in orbit. For the same size launchvehicle and total system power, it appears thatthe mirror system, which is the least massiveper kilowatt of the four alternatives, would re-quire the least number of flights, whereas thelaser system would require the most.

Other transportation scenarios have beenproposed (see ch. 5). With respect to thereference system, some of the environmentaleffects could be mitigated by changing theflight trajectory of the HLLV, the rocket fuel ofthe COTV or other transportation characteris-tics that present a problem. Laser propulsion,for example, has been suggested as an option.The tradeoffs associated with these designchanges would need to be studied as the SPSconcept evolved.

As an alternative to the HLLV, it has beenargued that economies of scale result fromincreasing t h e n u m b e r a n d f r e q u e n c y o flaunches of a vehicle much smaller than theproposed HLLV. 28 However, it is not clear howthe effects of more launches of a smallerrocket compare to the impacts of fewer flightsof a larger one.

A very different approach in the construc-tion of SPS wouId be the utilization of nonter-restrial materials. This could significantlyreduce the amount of terrestrial materials thatneed to be transported to space, and hencereduce the environmental impacts associatedwith the frequent launch of transport vehi-

‘ “ D L Aklns, “Optlmlzation o f Space Manufacturing Sy$-

terns, ” In Space Manufacturing From Non- Terre\ trla/ Materla/\, JGrey and C Krop (eds ) (New York Al AA, November 1979)

cles. 29 While the economics and technicalfeasibility of this concept have been eval-uated, the possible environmental impactshave not been studied and require consid-eration

Electromagnetic Interference

Each SPS transmission opt ion, whethermicrowave, laser, or mirror, has the potentialfor af fect ing other users of the electro-magnetic spectrum. In general, where such ef-fects occur they will be detrimental to one useror another, since most systems now depend onthe relative purity of the wavelength band theyuse.

Sharing the same air or ground space is pos-sible by operating at different frequencies andat specified power levels. This is most obviousfor radio frequencies, where the frequencyband width and power levels at which systemscan operate are assigned by national agenciesworking in accord with national and interna-tional standards. Where potential for inter-ference occurs in the radio frequency spec-trum, the power level and antenna character-istics of such interference are strictly regulatedin order to keep it below the available technol-ogy’s ability to filter out undesirable effects.The principle is to assure that electronic sys-tems are compatible with one another, i.e.,that interference from one system does notdegrade the overall performance of a second.

Because of the large amounts of power thatthe microwave, laser, or mirror SPS systemstransmit through the atmosphere, and the ex-tensive area covered by a full satellite de-ployment, potential interference effects wouldbe much greater than any other system whichnow use the electromagnetic spectrum. Theywould also be commensurately more difficultto ameliorate. Affected parties would includeusers of space and terrestrial communicationsand sensor systems, radar systems, various ter-restrial control devices, computers, radar andradio telescopes, optical te lescopes, and

.‘‘J (irev, $ate//lte P o w e r $y~tem rechrrlca/ Optlons and Eco-

non)l{ \ c on t rac to r report prepared for OTA, Nov 14, 1979


microprocessors. SPS systems using micro-waves for power transmission would generatethe greatest potential interference becausecommunications systems and passive receiversof alI sorts share this portion of the spectrum,as well as other electronic equipment (e. g.,computers, control devices, sensors) that aresusceptible to microwave energy. The refer-ence system is designed to transmit at 2.45GHz, the center of the Industrial, Scientific,and Medical band (ISM).

This analysis focuses on the affected userson an area-by-area basis. It is based on thepresumed characteristics of the three transmis-sion options of table 34. However, it should beemphasized, that the precise characteristics ofthe transmission beams are as uncertain asother details of the proposed alternative sys-tems. Not only are the characteristics of thesystems and their components poorly known,the theory is inadequate to extend known datato other frequencies, angles, or distances.Nevertheless, it is possible in most cases to in-dicate broadly the sources of potential in-terference and their effects on other users ofthe spectrum.

Potential Affected Users ofthe Electromagnetic Spectrum

SPACE COMMUNICATIONS

All artificial Earth satellites use some por-tion of the electromagnetic spectrum, eitherfor communication, remote-sensing or tele-metering data. All would be affected in someway by the SPS.

● Geostationary satellites. These would bemost strongly affected by the microwave sys-tems. They would experience microwave inter-ference from the fundamental SPS frequency(e.g., 2.45 GHz for the reference design) andnoise side bands, spurious emissions in nearbybands, harmonics of the fundamental SPS fre-quency, and from so-called intermodulationproducts. All radio frequency transmitters gen-erate harmonics and minor spurious compo-nents in addition to the desired signals. Theunintentional outputs are fiItered to satisfy na-t ional and internat ional regulat ions about

compatibi l i ty with other spectrum users.Receivers also generally include sufficient fil-tering to prevent degradation by the residualundesired signals. However, the magnitude ofthe power level at the central frequency and inharmonic frequencies for a microwave SPSwould be so great that the possibility of de-grading the performance of CEO and LEO sat-ellite receivers is significant. Examples of seri-ous interference include the 2.50 to 2.69 GHzdirect broadcast satellite band, the 7.3 to 7.45GHz space-Earth government frequency slot,’”and the S-band Nat ional Aeronaut ics andSpace Administration (NASA) space communi-cations channel.

I n addition to the direct effects from micro-wave power transmissions, geostationary com-munications satellites may experience “multi-path interference” from geostationary powersatelIites due to the latter’s sheer size. I n somecases, microwave signals traveling in a straightIine between two communications satelliteswouId experience interference from the samesignal reflected from the surface of the powersatelIite lying between them. CommunicationssatelIite uplink channels would be degraded bymulti path interference from the SPS vehicleduring orbit periods when the SPS is at a loweraItitude than the adjacent communicationssatelIites.

These adverse effects would necessitate alimit on the spacing that a geostationary satel-lite must have from a power satellite in orderto operate effectively. The minimum necessaryspacing would depend directly on the physicaldesign of the satellite, the wavelength at whichit operates, the type of transmission deviceused (i.e., klystron, magnetron, solid-statedevice), and the satellite antenna sidelobemagnitudes, transmitted power, orbit perturba-tions, and intermodulation product frequencydistribution and amplitudes.

Because a microwave SPS as currently con-figured must share the geostationary orbit withother satellites, the value of the minimum

“’John R Juroshek, “ T h e SPS I n t e r f e r e n c e P r o b l e m – Elec-

tronic S} ~tem Effects and Mltlgatlon Techniques, ” The Final f’ro-ceedlng~ ot the 5olar P o w e r Satellite P r o g r a m R e v i e w , C o n f

800491 f[lOE), pp 411-438


Table 34.—Summary of Electromagnetic Effects

System Spectral region Affected systems Mechanism/effect

MicrowaveMicrowave● Power radiation at central

frequency (2.45 GHz or someother choice)

Laser

Mirrors

● Harmonics of central frequency

● Spurious noise near central

● M u I i path interferenceInfrared● Thermal radiation from

all satellite components

All wavelengths(reflected sunlight)● Diffuse reflections● Specular reflectionsŽ Glints

Microwave● No discernible effect Infrared● Central beam radiation

. Thermal radiation from allcomponents

All wavelengths(reflected sun/ight)● Diffuse reflections● Glints

Microwave● No discernible effectInfrared● Thermal radiation from all

components

All wavelengths(reflected radiation)●

●

●

Specular reflection toterrestrial stationDiffuse reflection

Glints from structuralcomponents

Terrestrial

LEO satellitesRadio astonomy receivers

Deep space communicationsGEO satellitesRadio astonomy receiversGEO satellitesRadio astronomy receiversGEO satellites

Radio astronomy receivers

Infrared astronomy receivers

Optical telescopes

None

Infrared receivers nearterrestrial receiverRadio astonomy receivers

Scatter in atmosphere, fromrectenna

Pass through SPS beamsScatter from rectennas,atmosphereDirect interferenceDirect interferenceDirect interferenceDirect interferenceScatter from rectennasTwo-beam interference

Direct interference (raisedbackground). Satelliteappears as spurious sourceSatellite appears asspurious source

Sky background increased.Portions of sky obscured.

Direct interference (raisedbackground). Satelliteappears as spurious source

Optical telescopesProbably no effect

None

Radio astronomy receivers Direct interference (raisedbackground). Satelliteas spurious source

Optical telescopes near General sky brighteningterrestrial stationOptical astronomy Sky background obscured

around satelliteEffect probably small


necessary spacing has emerged as one of the rameters that are needed in order to calculatemost critical issues facing a geostationary SPS. the minimum required spacing. In addition,However, in the absence of a specific design, it even if the design parameters were known ac-is impossible to characterize the exact form curately, the theory of phased arrays is insuffi-and nature of the potential interference pa- ciently developed at present to predict the


minimum spacing with any accuracy. Es-timates range from ½0 to 10. 31 The lower Iimitwould probably be acceptable. However, aminimum spacing much greater than 10 would,result in too few available geostationary slotsto allow both types of users to share the orbitover the continental United States.

In 1980, some 80 civilian satellites sharedthe geostationary orbit worldwide, and by 1990that number is expected to increase substan-tially. Even though improvements in technol-ogy will lead to a reduction in the total numberof satel l i tes necessary to carry the samevolume of telecommunications services, totalservice demand is expected to rise dramati-cally. At present the minimum spacing fordomestic geostationary satellites is 40 in the6/4 GHz communication band and 30 in the14/12 GHz band. At these spacings, a total of90 6/4 GHz band satellites and 120 14/12 GHzband satellites could theoretically coexist atgeostationary altitudes, in the absence of SPS.Additional satellites could use other frequencybands without interfering with the above satel-lites, though this would ultimately be limitedby the station-keeping capability of the vari-ous satelIites. Multiple use platforms representone possible option to reduce contention overorbital spaces.

The laser and mirror systems in LEO wouldnot interfere substantially with geostationarysatellites. Even in the unlikely event that sucha satellite were to pass precisely between ageostationary satellite and its ground station,the time of passage as well as the apparent sizeof the occluding power satellite would be sosmall as to cause only a slight diminution ofthe signal.

● Other satellites. In addition to geostationarysatellites that would operate at the samealtitude as the GEO SPS, there are numerousremote sensing, communications, and nav-igation satellites in various LEOs that maypass through an SPS microwave beam. Pro-posed high-Earth orbit (HEO) satel l i teswould also be affected because of shad-

‘1 E Morrison, et al , SPS Effect$ on L[ ~) and GE() Sate//ite$,N T I A p u b l i c a t i o n (In pres$)

owing in the path from orbit to terrestrialstat ion by the large SPS vehicles, andreceiver interference thresholds that couldbe exceeded by the unintentional emissionsfrom the SPS platforms. They use a range ofoptical and microwave sensors, particledetectors, computers, and communicationdevices. Although the optical sensors are notdamaged by a microwave beam, increaseddevice noise can result in microwave inter-ference in related parts of the satellite. ” Anumber of shielding and filtering techniquesare available to ameliorate potential inter-ference. These would need to be tested forspecific satellite and deployment scenarios.Such satellites could protect their uplinkcommunications receivers from adverse in-terference by shutting down for that shortperiod (a few seconds) during SPS powerbeam traversal, or it might be feasible forthe SPS to shut down for the satel l i tepassage. ” For short-term SPS shutdown,high-capacity battery storage would have tobe Included in the ground segment (see ch. 9,sec B). This shutdown presents a severe con-trol problem (reduce power, start up again),as well as serious network load transfer com-plexities. It may also be possible for somesatellites to fly orbits that would not in-tersect the SPS beam. For example, satellitestraveling in an equatorial orbit at altitudeslower than 1,000 km would not intersect SPSbeams directed to rectennas at 350 latitudeor greater. Computer and processing/controlcircuit functions can be protected by im-proved module shielding and intercon-nection noise filtering.

The laser and mirror systems might interferewith nongeostationary satellites by causingreflected sunlight to blind their optical sensorsor by occluding communications beams. Ofthe two systems, the mirror system would be

“W H Grant, E 1 M o r r i s o n , J r , a n d K C D a v i s , “ T h e EMC

Impa[ t of SPS O p e r a t i o n s o n I.ow Ear th Orb i t Sa te l l i tes , ” TheI inal Pro( eeding~ of the Solar Power Satellite Program Review,Conf -80(M91 (DOF ), pp 411-434

‘‘P K ( h a p m a n , “ E ncounter$ Between SPS Power Beams and

Satel Iitei In 1 ower Orbits, ” [he F\na/ Proceedings of the SolarPower \,]te//lte Program Review, Conf -&100491 (DC) E) , p p

4284 W


most problematic because of the large size ofthe mirrors and their orbital speed. To date, noone has calcuIated the possible adverse effectsdue to this cause.

● Deep space communications. Because deepspace probes generally travel in the plane ofthe solar system (known as the ecliptic), theywould be especially affected by a geosta-tionary microwave SPS. As seen from theEarth, the ecliptic crosses the Equator in twoplaces. A microwave SPS would effectivelyprevent ground communication with theprobe when the latter happens to lie near thepart of the ecliptic that crosses the Equator.This interference is especially serious fordeep space vehicles because it is essential tobe able to communicate with them at anytime for the purposes of orbit control andfor t imely retr ieval of stored data. Thesusceptibility problem is more serious thannormal satellite communications links be-cause of receiver sensitivities and the lowsignal-noise ratios imposed by the longdistances from Earth station to probe.

It would be possible to avoid such inter-ference by establishing a communicationsbase for deep space probes in orbit. As wepenetrate deeper into space, this may be ad-visable for other reasons. Such a communica-tions station would effectively add to the costof the SPS.

TERRESTRIAL TELECOMMUNICATIONSAND ELECTRONICS

Both civilian and military terrestrial tele-communications and electronic equipmentwouId suffer from a number of possible effectsof a microwave beam. Direct interference canoccur from the central frequency and har-monic emissions. In addition, scattered andref lected radiat ion from the rectenna andstructure intermoduIation products couldcause additional interference problems for ter-restrial receivers. At the very least, rectennaswould have to be located far enough from crit-ical sites such as airports, nuclear powerplants,and miIitary bases to render potential inter-ference as small as possible. In addition, mostequipment would have to be modified to per-

mit far better rejection of unwanted signalsthan is now necessary. This appears to be tech-nically feasible; primary concerns would bemodifications to the shielding of sensitive cir-cuitry. The initial estimate of the cost of modi-fying terrestrial electronic equipment is in therange of 0.1 to 5 percent of the unit cost (ap-proximately $130 million for the 1980 estimateof the inventory of susceptible equipment).

The EMC evaluation program determinedthat most terrestr ia l e lectronic equipmentwould be unacceptably degraded by SPS inter-ference for power levels possible within a 50-to 75-km distance of a rectenna site. The mostsensitive equipment, such as high capacitysatellite terminals and radio astronomy re-ceivers would be adversely affected at dis-tances of 100 to 200 km.

Mitigation techniques have been evaluatedfor radars, computers and processors, sensors,and muItichannel terrestrial microwave com-munications. With the exception of the mostsensitive receivers, modifying shielding andgrounding procedures and using rejectionfilters in radar and communications receiverswould allow most systems to operate with theSPS interference levels expected at the recten-na site boundary. Special mitigation tech-niques for more sensitive systems involving in-terference cancellation methods have beenconsidered, but they must be tested to deter-mine the range of protection possible.

EFFECT ON TERRESTRIAL ASTRONOMYAND AERONOMY

None of the proposed SPS systems couldbenefit astronomical research except insofaras they would indirect ly provide a t rans-portation system for placing large astro-nomical facilities in space. Their detrimentaleffects would vary depending on the systemchosen. The impacts of a microwave systemwould likely be severe for both optical and

‘1 Morrl\on, “SPS S u s c e p t i b l e Systems Cost Fac to rs – lnvest-

111 ent 5 u (m m a ry and M It I gat Ion Cost I nc rernent E st I ma tes, ” I n

l)res~

‘P A t kstron and C M Stokes, “Work$hop o n S a t e l l i t e

I)ower ~y~tem~ (SPS) Effects on Optical and Radio Ast ronomy, ”

( ont 7 ’ )05141 (DOE)

Ch. 8—Environment and Health • 195

radio astronomy. An infrared laser system 36

would have fewer detrimental effects on bothforms of astronomy than the reference system.The mirror system would have its most seriouseffect on optical astronomy.

● Optical astronorny. For the reference sys-tem, diffuse reflections from the satellitestructures would cause the greatest degra-dation for terrestrial telescopes. Becausethey appear to remain stationary along thecelestial Equator, reflected Iight from a sys-tem of 15 to 60 satellites would meld to-gether to block observation of faint objectsover a large portion of the sky near theEquator for telescopes located between thelongitude l imits of the satel l i tes. Somemajor foreign, as well as most domestic ob-servatories would be affected. Observationsof bright objects would be possible, but de-graded in quality. In addition, reflected lightfrom the LEO construction base could be ex-pected to interfere with observations offaint sources in its vicinity. Telescopes inorbit, such as the U.S. Space Telescope, tobe launched in 1984, will travel in nonequa-torial orbits and therefore would not beaffected significantly by a reference systemSPS. The danger of pointing directly at ageostationary satellite will increase the com-plexi ty of the te lescope-point ing mech-anism. Astronomical photometry and spec-trometry instrumentat ion, and high res-olution telescope tracking systems would bedegraded if located within 50 to 60 km of arectenna site. The EMC evaluation programindicated the necessity of improving sensorand sensitive circuit shielding, and main-taining a minimum separation distance of 50to 60 km between rectenna sites and tele-scopes using sensitive electronics to removeSPS induced degradation.

The effect of diffuse reflections from alaser SPS in LEO could be expected to causefewer problems for observations of diffuseobjects near the Equator because the lasercollection and transmission satellite wouldbe constantly in motion. Thus, no part of the

‘“C Baln, Potential of Law for 5P$ Power rran$ml$~lon, SPS

CDEP, October 1978

sky would be permanently blocked fromview. The relay satellites located in CEOwould not be Iikely to interfere with opticalobservations. However, large moving sat-ellites would present optical astronomy withanother observational obstacle. Scatteredlight from them would vary in intensity asthe satellite passes near a celestial object ofinterest, making calibration of the nearbybackground radiation very difficult if notimpossible. Photographic exposures of faintcelestial objects may last from 1 to 3 hoursand individual photographs cannot beadded effectively. The laser satellite wouldinterfere with infrared astronomy studies in-volving wavelengths adjacent to the trans-mission wavelength of the beam.

The mirror system, which would involve anumber of large, highly reflective movingmirrors in LEO, wouId have very seriouseffects on optical astronomy. While the pre-cise effect has not been calculated, it wouldrender a large area around the ground sta-tions totally unacceptable for telescopicviewing. Because of diffuse reflections fromthe atmospheric dust and aerosols above theground station, the individual mirrors wouldcreate moving patches of diffuse light thatwould preclude studies of faint objects thatlie in the direction of the satellite paths.Radio astronomy. Radio astronomy wouldsuffer two major adverse affects from micro-wave systems: 1) electromagnetic interfer-ence from the main PS beam, from harmon-ics, from scattered or reflected SPS signals,and from reradiated energy from rectennas;and 2) increasing the effective temperatureof sky noise background, which has the ef-fect of lowering the signal-to-noise ratio ofthe radio receivers. Studies of faint radio ob-jects near the Equator would be renderedimpossible. In addition, rectennas wouldhave to be located more than 200 km fromradio observatories and in terrain that wouldshield the observatories from reradiatedmicrowave energy. Also of concern to radioastronomers is the possibility that expectedfailures of the klystron or other microwaveemitting devices would resuIt in spuriousnoise signals that would further disruptradio astronomy reception.


Neither the laser nor the mirror systemswould contribute to the first effect. However,they would raise the effective temperature ofthe sky background. Low-level measurementssuch as scientists now routinely conduct, forexample, to measure the amount of back-ground radiation from the primordial explo-sion of the universe would thus be extremelydifficult if not impossible from terrestrial sta-tions. Many other types of sensitive radioastronomy observations would be seriouslydegraded.

The susceptibility of radio astronomy re-ceivers results from their high sensitivity, andthe wide range of observing frequencies in themicrowave spectral region. Mitigation tech-niques effective for other electronic equip-ment are only marginally useful because of thesensit iv i ty factor and associated dynamicrange. A preliminary review of interferencec a n c e l i n g t e c h n i q u e s i n d i c a t e s t h a t t h i smethod has a high probabiIity of providing re-jection of SPS signals to a level that wouldallow rectenna sites to be located within a 100-to 150-km range from radio astronomy fa-cilities. Detailed design and testing at a radioastronomy receiver is necessary because of theunique aspects of integrating a canceler func-t ion into such complicated and sensit ivereceivers.

Space basing of radio telescopes, especiallyon the far side of the Moon, would eliminatethe impact of SPS and other terrestrial sourcesof electromagnetic interference. However,such proposals, though attractive from thestandpoint of potential interference, are un-likely to be attractive to astronomers for manydecades because of their high cost and relativeinaccessibility.

● Optical aeronomy. Much of our knowledgeof the upper atmosphere is gained by night-time observations of faint, diffuse light.Some of the observations that are made to-day must be carried out in the dark of theMoon. The presence of satellites whose in-tegrated brightness is equal to a quarterMoon would effectively end some studies ofthe faint airglow and aurora. Other observa-tions would be severely limited in scope.

Terrestrial Activities

The terrestrial environment would be af-fected by SPS in a number of ways. The con-struction and operation of receivers couldalter local weather, land use, and air and waterquality. The mining, manufacturing, and trans-portat ion associated with SPS could alsoadversely affect the environment.37

Land Use and Receiver Siting

Land use and receiver siting are importantissues for SPS, especially from a politicalperspective (see ch. 9, Issues Arising in thePublic Arena).* This is due in part to themicrowave and mirror system land require-ments for large contiguous areas for receivingstations and transmission lines. In sitingreceivers, tradeoffs wouId have to be made be-tween a number of parameters such as the to-pography and meteorology of the candidatelocations, local population density, land andtransmission line costs, electromagnetic in-terference, and electricity demand, as well asenvironmental impacts. The construction andoperation of SPS receivers wouId have measur-able effects on the ecology, soil, air and waterquality, and weather of the receiver area. 3 8

Since many of these impacts are site-specific,an extensive program wouId have to be carriedout in order to locate and assess each pro-posed site.

The severity and extent of the environmen-tal impacts of SPS ground receivers and trans-mission lines would also depend on which SPSsystem is deployed. For example, as shown intable 7, the baseline mirror system (1) woulddeliver power to a few, extremely large sites,whereas the laser system might be designed to

“5ate//lte Power System, Concept t3evelopment and Eva/ua-tlon Program, re ference sys tem repor t , DOE/E R-0023, October

1978

‘The major i ty o f remarks made In this section pertain to land-

based rece iver s i tes as specif]ed by the techn ica l sys tems ad-

ciressed In this report It I S I m p o r t a n t t o n o t e , h o w e v e r t h a t off-

~hore r e c e p t o r sltlng tha t may alleviate s o m e o f t h e p r o b l e m s

,) ~soc Iated with land-based s Ites IS a I so possible

‘“ fnbjronmental Assessment for the Satelllte Power System( oncepf lleve/opment and Eva/uatJon Program, DOE’E R-0069,Augu~t 1980


generate the same amount of power at a greatnumber of sites, each of which is two to threeorders of magnitude smaller than the mirrorsites. Smaller mirror system (1 1) sites are alsopossible.

For safety purposes, buffer zones would beestablished around each site. For the laserdesign, the infrared power density at the edgeof this zone would be 10 mW/cm 2 (see fig. 33).As shown in figure 34, the microwave powerdensity at the edge of the reference system ex-clusion boundary would be 0.1 mW/cm 2. If mi-crowave standards become considerably morestringent, SPS land requirements could in-crease. For example, if the power density atthe edge could not exceed 0.01 mW/cm 2 (theSoviet standard), then each site would requirealmost 1,700 km 2 of land. 39

In addition to land for receivers, about 20 to8 5 0 k m 2 would be needed for launch facil-ities. 40 This could be made available throughexpansion of the Kennedy Space Flight Center

Figure 34.—Microwave Power Density at Rectennaas a Function of Distance From Boresight

2.45 GHz50

23 mW/cm 2

10

5

1.0

“J B Black burn, Power Mapping of for D O E / N A S A R e p o r t H C P /

R-4024-10, October 1978

.01

Figure 33.— Receptor Site Protection Radius as aFunction of the Perimeter Laser Power-Density Level

10

10’1 0 - 3 10– 2

10- ‘ 10” 10’Perimeter power density, W/cm 2

SOURCE: R. E. Beverly, Satellite Power Systems Laser Report—Laser Environmental vol.

Rockwell International report, SSD 80-0119-1.

.005

.001o 5,000 10,000 15,000 20,000

Ground radius, m

SOURCE Satellite Power System, Concept Development and Evaluation Pro-gram, reference system report, DOE/ER-0023, October 1978.

in Florida, although environmental considera-tions might preclude this option. Transmissionline, mining, and transportation land uses arenot considered in table 35. More analysis isneeded to determine these impacts and to ex-

plore tradeoffs between centralized and dis-persed electricity systems with respect totransmission line siting. In table 36, the SPS ref-erence system is compared to other electricitypowerplants.


Figure 35. —Rectenna/Washington, D.C. Overlay

Washington , D C


Some of the environmental, societal and in-stitutional problems associated with land-useand receiver siting might be remedied by sitingreceivers in shallow offshore waters. For someland-scarce areas such as New England andEurope, this concept is particularly desirable.

The taper of the solid-state power-transmissionsystem makes offshore siting particularly at-tractive. A few preliminary technical studieshave been conducted,” including an offshorerectenna siting study,42 (see fig. 36). However,little attention has been paid to the environ-mental ramifications of offshore siting. Areasof special concern include the effects onweather and ecosystems from thermal releaseand the effects of microwaves on aquatic lifeand birds that might be attracted to thereceiver

Land-use problems might also be alleviatedby innovative receiver designs that would per-mit multiple land use under the receivers, suchas crop agriculture, biomass production andaquaculture.43 Again, however, until the bio-logical effects of microwaves and reflectedsun Iight are better understood, the environ-mental impacts and hence viability of theseideas are largely unknown.

.——4 J Freeman, et al , So/ar Power Sate//ite Of f$frore Rectenna

Stur/y, contract report No NAS 8-33023, prepared for Marshall

$pace Flight (-enter, May 1980

‘ ‘i]tellite Power $y\tem [5PS] Rectenna $Itlrrg A vallablllty andLl~~trlhurjon of Nor-n jna//y E/jglb/e Sites, DC) E/E R-10041-TI O, No-

vem ber 19 8 0

‘ Crey, [Jp c It

Table 35.—SPS Systems Land Use

Number of Total land areasites for (kmz)

SPS system k m2/site km2/1,000MW 300,000 MW for 300,000 MW m2/MW-yr a

Reference . . . . . . . . . . . 174.0 35.0 60 10,400.0 1,280Solid statec . . . . . . . . . . . 50.0 33.0 180 9,000.0 1,230Laser Id. . . . . . . . . . . . . . . 0.6 1.2 600 360.0 44-35e

Laser Ilf . . . . . . . . . . . . . . 40.0 80.0 600 24,000.0 2,960-3,550 e

Mirror If . . . . . . . . . . . . . . 1,000.0 7.4 - ’29 2,200.0 274-329 e

For comparisonWashington. . . . . . . . . . . 174.0New York City. . . . . . . . . 950.0Chicago. . . . . . . . . . . . . . 518.0

a These “nlt~ are presented for ~O~ParlSOn with table 36, The values for the reference and solid-state designs assuf’rle a so-year lif@tirne and a capacity factor Of ().9.b Rectenna at 34o latitude covers a $jkrn x lskrll (1 ITkrnt) elliptical area, Microwave power density of edge of rectenna is 1.0 mW/cm2. If an exclusion boundary iS Set at

0.1 mW/cm2, then the total land per site is approximately 174 kmz (2 km extra on each side for buffer zone). J. B. Blackburn, Sate//ire Power System (SPS) Mapping ofExc/usion Areas for Rectenrra Sites, DOE/NASA report No. HCP/R-4024-10, October 1978, Does not include land for mining or fuel transport.

C The solid-state sandwich design is described in J Grey, safe//j~e power sys~em ~ecffr’rjca/ op~lo~s and Economics, contractor report prepared fOr OTA, NCrV, 14, 1979.d Laser 1 and Laser 11 are two laser systems considered by DOE, Both deliver the same amount of power but the beam of Laser I iS more narrow (and hence more intenSe)

than that of Laser Il. See C. Bain, Potentia/ of Laser for SPS Power Transmission, SPS CDEP, October 1978.e The values for the laser and mirror systems assume a 30-year lifetime and Capacity faCtOrs of 0.75-09f Minor system parameters are defined by SOLARES System as described in K. Blllman, W P Gllbreath, S. W. Bowen, “Solar Energy Revisited With Orbiting

Reflectors,” NASA, Ames,g The SO LARES system is designed to deliver 810 GVV to 6 sites; 2 SOLARES sites actually ~)rovlde 270 GW,


Table 36.—Summary of Land Requirements

Purpose Construction Plant F u e l Disposal Transmission—CG/CCQuantity —a 7.2-150 m21MW-yr

Duration —c 30 yrLocation —c —c

FBCQuantity —a 5.2-16.8 m2/MW-yr


1,800-4,520 5 m21MW-yrm2/MW-yr

30 yr —c—c —c

—c 1.4 m2/MW-yr

—c —c—c —c

300 m21MW-yr(480 km)b

30 yr—c

300 m2/MW-yr(assume same ascombined cycle)

30 yr—c

L WRQuantity —a 57-174 m2/MW-yr

Duration —c 30-40 yrs(20 m2/MW-yr“permanent”)

Location —c —c

31 m2/MW-yr 4 m2/MW-yr 225-1000m 2/MW-yr

(480-1600 km)b

30 yr 1 06 years 30-40 yrs

—c —c —c

LMFBRQuantity —a 76-133 m2/MW-yr


5 m2/MW-yr —c 200 m2/MW-yr(plant life- (80 km)b

time) and.25 m2/MW-yr(permanent)

—c —c 30 yr—c —c —c

.—TPVQuantity —a 600-3,800 m2/MW-yr neg 1d neg 1d 300-3,000

(depending on cell m2/MW-yrefficiency and (480-4,800 km)b

capacity factor)Duration —c 30 yr N Ae N Ae

30 yrLocation —c Southwest NA NA —c

STEQuantity —a 2,260-6,650 m2/MW-yr neg1d neg1d 300-3,000

m2/MW-yr480-4,800 km)b

Duration —c 30 yr NA NA 30 yrLocation —c Southwest NA NA —c

OTECQuantity —a neg1 neg1d

n e g 1 d 300 m2/MW-yr(480 km)b

Duration —c N Ae N Ae

N A e 30 yrLocation —c N Ae

NA NA —c

SPSQuantity 20-850 km2 1,480 m21MW-yr g neg1d neg1d 300-1,000

(launch) (rectenna) f m2/MW-yr(480-1,600 km)b

Duration 30 yr 30 yr N Ae NAe

30 yrLocation Florida? —c NA NA —c

approximately the Sum of plant and transmission requirements. ‘N A-Not applicablebDist ance to load center. flncludes buffer zone, rectenna proper OcCIJpleS about 50°1. Of total.cData lacking; some categories are discussed I n test 9Assuflles 200 krnz per rectenna site.‘Negligible.

SOURCE: D. E. Newsom and T. D. Wolsko, Prelirnmary Cornparatwe Assessment of Land Use ~Or Satelhte Power Systems and Altemafive E/ecmc Energy Technologies,DOE/NASA report No. DOE/ER-0058, April 1980.


Figure 36.—Offshore Summary Map

I

Offshore siting study - dark areas are not eligible for rectenna siting

SOURCE: Satellite Power System of 1OO41-TIO, November 1980.

If SPS is to be deployed on a multinationalscale, the siting constraints may be differentfrom those in the United States. This is espe-cialIy true with respect to microwave exposurestandards, which in some countries are morestringent than in the United States (see Healthand Ecology, Microwaves). The environmentalstandards of other nations and their effects onSPS siting requirements need to be explored inmore detail.

A sit ing study for the continental UnitedStates has been conducted for the referencesystem to determine if 60 candidate sites canbe found. ” The United States was divided intogrids, each approximately the size of a rec-tenna. Grid squares were eliminated from con-sideration if they violated a set of “absolute”exclusion variables that included inland wa-ters, high population density areas, marsh-lands, military reservations, habitats of endan-gered species, Nat ional recreat ion areas,

B. and B A “Satellite Power System Siting Study, ” in Proceedings of the

Power Program Review, Apr 22-25, 1980, DOE/NASA

report No Conf -800491, July 1 9 8 0

Atomic Energy Commission lands, and unac-ceptable topography. Sites were also excludedif they were found within a specified distancefrom military installations, nuclear power-plants and other facilities that might sufferfrom electromagnetic interference with theSPS microwave field.

In figure 37, ineligible grids were markedwith an “x.” In this first exercise 40 percent ofthe United States remained eligible. After theapplication of addit ional “potential” exclu-sion variables that were categorized as havingan unknown or adverse, but potentially cor-rectable impact (e. g., agricultural lands andflyways of migratory waterfowl), 17 percent ofthe United States remained eligible. In general,the greatest number of eligible sites was foundin the West, Southwest, and in the northernregions of the Midwest; the least number of eli-gible sites occurred in the Mid-Atlantic States,where 3 to 10 percent of the land was eligible(31 to 83 grids, depending on the criteria foreligibility). The exclusion variables that hadthe greatest incremental effect in renderingland ineligible included topography, popula-


Figure 37.—Satellite Power System—Societal Assessment

SOURCE: Satellite Power Svstem (SPS) and of Nominally Eligible Sites, DOE/ER-1OO41-TIO, November 1980.

tion and electromagnetic compatibility’ (abso-lute variables) as well as private agriculturallands, flyways, and Federal dedicated and pro-tected lands (potential variables).

The siting study also revealed an importantpoint about the siting of smaller rectennas.Smaller site sizes could increase the likelihoodthat sites identif ied as eligible (in the firstapplication of absolute exclusion variables)would remain so upon closer examination in a“validation” process. However, they would beunlikely to make previously excluded gridsquares eligible. Therefore, it was concludedthat smaller rectenna size (i. e., one-fourth orone-half the rectenna area) would not make asubstantial difference in the siting process. 45

The effects of eliminating isolated sites werealso considered on the assumption that localvariations and the problems associated withpublic or private land acquisition would makesiting more difficult in areas that did not con-tain a large number of adjacent eligible grid

*This was also an important constraint for the siting of off-shore

“Ibid

squares. By imposing the constraint that eligi-ble sites had to fall within a 3 x 3 grid pattern,the amount of eligible sites dropped dramati-cally, especialIy in the Mid-Atlantic region andthe Southeast. A less restrictive requirementsof 2 x 2 grid patterns produces a considerablyless drastic result.

The siting results (from the application of“absolute variables”) were then correlatedwith the distribution of projected electricald e m a n d . 46 Based on one projection of futureelectricity demand, it was concluded that theonly potential site scarcity would occur in theMid-Atlantic region (see fig. 38). In most otherregions there wouId be about 100 times moreeligible grids than “required” sites. Scarcity oflarge load centers relative to allocated recten-nas could be a problem in sections of the Mid-west and West.

A prototype environmental assessment wasconducted for a rectenna site in the Californiadeser t (Rose Val ley, 250-km nor th of Los

“ A “Re la t ionsh ip o f E l ig ib le Areas to Pro jec ted

Demand , “ in The Final Proceedings of the Solar Power Program Review, Apr 22-25, 1980, DOE/NASA report No

-800491”, July 1980

83-316 0 - 81 - 14


Figure 38.—RegionaI Generation (2000) and Rectenna Allocations

18.40/o

600

Note: This is based on the EIA Leap Series C (1978) protection of electricity the year 2000 which assumes a 4 10/. growth rate per year from 1977-1995. See chapter VI or discussion on alternative electricity growth rates

SOURCE. A. of Areas to Projected Elect Demand,” Proceed/rigs Power Satellite Program Apr 22-25, 1980, DOE/NASA No conf -800491, July 1980

Angeles).” The major environmental impacts(excluding microwave effects) and possiblesolutions are summarized in table 37.

The assessment emphasized that largeamounts of contiguous land area must be com-plete ly commit ted to the pro ject , to ta l lydisplacing existing land use and completelyaltering the existing natural environment. in-vest igators a lso noted that a f ter the s i teboundaries are selected, there is no flexibilityin the siting of individual rectenna structures,so that areas particularly sensitive to SPS im-pacts could not be avoided. To alleviate ad-verse effects, they recommend that land areas

ype Environmental Assessment of the Impacts of Sitingand Constructing a Satellite Power System Ground Receiv-ing Station DOE/NASA report No DOE/E R-O072, August1980

much larger than the minimum requirementsbe located in the site selection process. In ad-dition, the study recommends that: 1) rectennapanels be light and open to allow passage ofsunlight and rain; 2) natural characteristics ofthe site be considered in the panel and diode/dipole design, e.g., taking account of possibleattraction birds and rodents might have to thepanels for resting or nesting; and 3) the designminimize the use of materials.

Finally, investigators note that the siting ofreceivers in the Southwestern United Stateswill be especially hampered by land-use con-flicts with other energy sources, archaeologicalsites and military programs. In particular it ispointed out that 15 percent of the CaliforniaConservation Area is reserved for defense pur-poses.


Table 37.—Summary of Environmental Impacts of Rectenna Construction andOperation at a Specific Study Site

Technical area Rectenna construction Rectenna operation Mitigation

Air quality and climatology . Probable standards . No significant air quality ● Adequate dust suppressionviolation for nitrogen impacts. program during constructionoxides, particulate, ● Unknown, but possibly would mitigate particulateand hydrocarbons. significant microclimateic impacts.

● No climatic impacts. effects at or near ground . Extending constructionsurface schedule would reduce

emission peaks for hydro-carbons and nitrogen oxides.

● Pending further research,project modifications mightbe needed for ground sur-face microclimate impact

Noise ● Substantially elevated . No significant impact. ●

noise levels, but inareas with low popula-tion density,

● Possible impacts onnoise-sensitive ●

species.

Geology and soils ●

●

●

●

●

Geologic impacts lessimportant thangeologic constraints.Study area very activeseismically, but withinnormal range forsouthern California.Soils impacts signifi-cant: large disturbedarea, compaction,wind/water erosion.Soils constraints: di-versity of soils typesimplies variability inengineering properties(e.g., shrink/swellpotential, corrosivityto metals/concrete).

Improved noise controltechnology by constructiontime frame for vehicles,equipment, and processeswould mitigate impacts.During construction, noise-sensitive habitats should beavoided to maximum extentpossible during breedingand nesting seasons.

● Seismicity has potential . Thorough seismic and soilsfor facility destruction studies required as part ofor loss of efficiency site-specific engineering.(alinement v. satellite). ● Careful soiI-stabilization/

● Soil productivity impacted age/erosion-controlfor project life: depends programs required.on extent and degree ofconstruction—phase andongoing operations dis-turbance.

Hydrology and water quality ● Project requirements:2-14 x 106 m 3

(depends on dustsuppression methodsused).

● Meeting project needsfrom groundwaterwould lower watertable 0.2-1.5 m/yr;would reduce under-flow to adjoiningvalley, could lowerwater level in nearbylake; might con-taminate usable waterthrough hydraulic con-nection with unusableground water.

. Project requirements minor ●

unless major revegetationprogram undertaken.Revegetation could require ●

27 x 106 m 3/yrfor 3 yr, that couldcause water tabledrawdown.

●

Careful soil stabilization/drainage/erosion-control program required.Ground water withdrawalimpacts could bealleviated by importingwater from outsidestudy area.Proper sewage controlprogram necessary duringconstruct ion to preventwater quality degradation).


Table 37.—Summary of Environmental Impacts of Rectenna Construction andOperation at a Specific Study Site-Continued

Technical area Rectenna construction Rectenna operation Mitigation

Flora ● Land disturbance ● Impacts similar to ● Reestablishment ofwould completely construction phase. preexisting fIoramodify site’s ● Microclimate changes at problematic; majorfloral communities. ground surface a key and difficult revegetation

● Possible indirect issue for severity program required.impacts on flora from and potential for ● Careful placement ofhydrologic changes, mitigation of floral ancillary facilities necessaryair and water impacts. to minimize impactspollutants, and on sensitive habitats.personnel activities ● Careful planning,

● No endangered design and construction/species present operations practicesat Rose Valley/ necessary to minimizeCoso; one rare indirect impacts (e.g.,

Land disturbance ●

would completelymodify site faunal ●

communities.Possible indirectimpacts on fauna ●

from hydrologicchanges, air andpollutants, personnelactivities, and lossof feeding areasfor nearby fauna.Surface watersources formigratory waterand land birdswould be lost(Playas) andjeopardized (LittleLake).One protected species(Mohave groundsquirrel) found in Rose

species present. water quality degradation).

Fauna ●

●

Impacts similar to ●

construction phase.Impacts closelyrelated to fIoraimpacts.Microclimate changesat ground surface ●

a key issue forseverity and potentialfor mitigation offauna impacts.

●

●

Valley.

Land use ●

●

●

●

Reestablishment ofpreexisting faunaproblematic; closelylinked to strategyand success offloral mitigation.Careful placement ofancillary facilitiesneeded to minimizeimpacts on sensitivehabitats.Careful planning,design, construction,O&M practices, andconstruction schedulingneeded to avoidindirect impactsand to avoidsensitive habitatsduring breeding andnesting seasons.

Total displacement Same as construction ●

of existing site phaseuses (e. g.,farming grazing,recreation).Minor loss ofmineral resources(cinder, pumice).Minor indirect(growth-relatedimpacts.Potential landacquisitior/useconflicts with Navy(China Lake NWC),energy (geothermal),wilderness,archaeologicalresources, nativeAmerican use andaccess to culturaland religious sites.

Major impacts couldnot be mitigated.It might be possibleto achieve jointuse of rectennasites but thisremains speculative.

SOURCE: Prototype Environmental Assessment of the Impacts of Siting and Constructing a Satellite Power System (SPS) Ground Receiving Station (GRS), DOEINASAreport No. DOE/ER-0072, August 1980.


Receiver Structure: Weather Modification

Other DOE studies have investigated the po-tential of the rectenna for modifying localweather. They indicate that the surface rough-ness and albedo of the rectenna structure andthe waste heat generated by rectenna opera-tion (750 MW per site) would have a small, butdetectable impact on regional weather and cli-m a t e . 48 49 In particular, rectennas would per-turb the average surface heat exchange byabout 10 percent. SPS land-use changes couldalter temperature (on the order of 10 C), clouddensity and rainfall. However, it is importantto note that these effects would be no greaterthan those attributable to other nonindustrialurban activities. For example, the waste heatgenerated by typical coal and nuclear plantsrange from 750 to 6,000 MW. The waste heatrejected at laser receptor sites, would also pro-duce weather effects that would be less signifi-

48 Environrnerrta/ Assessment for the Sate//ite Power SystemConcept Development and Evaluation Program, op cit.

“Proceedings of the Workshop on Meteorological Effects of Sat-ellite Power System Rectenna Operation and Related MicrowaveTransmission Prob/ems, Aug 23-25, 1978, DOE/NASA report NoConf -7808114, December 1979

cant than those associated with nuclear plantsof comparable power. 50

Resources

The construct ion and operat ion of SPScouId strain supplies of some critical materi-als, as shown in table 38. The most seriousproblems arise for the solar cell materials (e. g.,gallium, gallium arsenide, sapphire, and solargrade silicon) and the graphite fiber used forthe satellite structure and space constructionfacilities of the reference system. 51 It appearsthat the silicon SPS systems pose less seriousproblems than the gallium arsenide option, butthis may be due to the immature state of gal-lium arsenide technology. The most serious re-source strain for the galIium arsenide system isgallium; for the silicon option, large amountsof electricity might be needed to produce thecells.

‘OBasu, Johnson, Klobuchar, and Rush, op clt“ R R Teeter and W M jamieson, Prel iminary Materia/s

Assessment for the Sate//ite Power System (SPS), DOE/NASAreport No DOE/E R-0038, January 1980

Table 38.—Summary of Materials Assessment Results

World PercentPercent production SPS Net world

supplied as growth percent of percent resource costParameter byproduct rate demand imported consumption $IkwThreshold valuea . . . . . . . . . . . . 5 0 % 1 0 % 100/0 50% 200% $50/kwGallium. . . . . . . . . . . . . . . . . . . . A A A —Graphite fiber. . . . . . . . . . . . . . . —

— —A A — A

Sapphire. . . . . . . . . . . . . . . . . . . ——

A A — ASilicon SEG . . . . . . . . . . . . . . . . –

—A A — A

Gallium arsenide. . . . . . . . . . . . ——

A A — AElectricity. . . . . . . . . . . . . . . . . . —

—— — — A

Arsenic/arsenic trioxide. . . . . .—

B — — BKapton . . . . . . . . . . . . . . . . . . . . —

— —B B —

Oxygen (Iiq) . . . . . . . . . . . . . . . . –— —

B B —Silica fiber . . . . . . . . . . . . . . . . . —

— —B B —

Silver. . . . . . . . . . . . . . . . . . . . . .— —

B — — BSilver ore . . . . . . . . . . . . . . . . . . —

— —— — B B

Glass, borosilicate . . . . . . . . . . ——

— B — —Hydrogen (Iiq) . . . . . . . . . . . . . . —

—B — —

Mercury . . . . . . . . . . . . . . . . . . . —— —

— — BMercury ore . . . . . . . . . . . . . . . . —

— —— — B

Methane. . . . . . . . . . . . . . . . . . . —— —

B — —Petroleum. . . . . . . . . . . . . . . . . . —

— —— — — B

Steel . . . . . . . . . . . . . . . . . . . . . . ——

— — — BTungsten . . . . . . . . . . . . . . . . . . —

—— — B — —

Note: “A” signifies problem of serious concern “B” signifies problem of possible concern.aparameter Value above Which a potential problem exists. Materials in this table exceeded these values where an “A” or “B” is recorded.

SOURCE: R. R. Teeter and W. M. Jamieson, Prelimlrrary Materials Assessment for ttre Satellite Power System (SPS), DOEINASA report No. DOE/ER-0038, January 1980.


Most of the resource constraints identifiedstem from limitations in production capacityrather than exhaustion of reserves. SPS couldcompete for graphite composite with the auto-mobile industry and, depending on its time ofintroduction, with terrestr ial photovoltaictechnologies and the electronics industry forsemiconductor materials. The demand by SPSfor a few materials such as gallium, tungsten,and mercury could also increase U.S. depend-ence on foreign sources. Further analysiswouId be required to determine the severity ofthe resource l imitat ions identi f ied for thereference system and possible measures thatwouId circumvent them.

While no assessment has been made of thematerial requirements for any of the other SPStechnical options, a few observations can bemade. The solar celI, graphite, and transporta-tion materials that are problematic for thereference design might also be used in thethree other options. The solid-state design callsfor silicon or gallium arsenide devices in thetransmitting antenna as well as in the solar col-lector. While the solid-state satellites would besmaller than the reference design, the solid-state material needs per unit energy would begreater. Therefore, if the reference design wereto strain supplies of semiconductor materials,the solid-state variant most certainly would taxthem as well (assuming that both systems de-liver the same total amount of power and usethe same materials). The laser and mirror sys-tems would require slightly less photovoltaicmaterial per kilowatt of delivered electricitythan the reference system. The quality of thephotovoltaics mater ia l used in the mirrordesign might be different than the referencematerials however, since in the mirror systemthey would be placed on the ground. AII of thesystems would require graphite for structures,and fuels for space transportation. Furtheranalysis is required in order to compare thematerial requirements o f the a l t e rna t i vedesigns to the reference system. Moreover, theeffect on SPS material requirements of usingnonterrestrial materials (lunar soil containsaluminum, titanium, iron, silicon, and oxygen)and developing space processing and in-dustrial capacity needs to be investigated.

Mining, Manufacturing, and Transportation

The minerals extraction, materials process-ing, manufacturing, and transport activitiesassociated with SPS could result in a meas-urable increase in air and water pollution andsol id wastes. 52 For example, the potential envi-ronmental impacts of mining include waterpollution from leaching and drainage mod-ifications, air pollution from fugitive dust andland disturbance from strip mining, subsidenceand spoil piles. Manufacturing would producestack emissions, process effluents and solidwastes. In table 39, order-of-magnitude esti-mates have been made of some of the environ-mental impacts resulting from these referencesystem activities. The incremental domesticprocessing of materials required for SPS canalso serve as a rough guide to increased pollu-tion levels.

While these exercises help ident i fy thepotential scope and extent of environmentalimpacts, a thorough and quantitative assess-ment is presently lacking. However, i t isanticipated that most impacts would be con-ventional in nature and could probably beminimized by methods currently used in indus-try 5‘ There is no information on similar effects

‘ /’rfj[o/ I I)(I I nvlronrrrent,]/ A >je~smerrt ot the /rrrpactj ot fi(lng,2 n(l ( on\ [ rj 1 f t /nLJ ,] S<l tcI//l te Power \ yj tern / $ P$ / (; ro~in(/ Recel tIng }t,It IoII (, R ‘i/, DC) E NASA repot-t No DOE E R-()()72, Augu\t1 ()~()

I Ibid

Table 39.—Annual Environmental Effects of SPSa

(mining, processing, manufacture,and ground-based construction)

Air pollutants Percent U.S. totalc

Particulate . . . . . . . . . . . . . . . . . . . . . . 0.8%Sulfur dioxide. . . . . . . . . . . . . . . . . . . . . 0.04Carbon monoxide . . . . . . . . . . . . . . . . . 0.05Hydrocarbons . . . . . . . . . . . . . . . . . . . . 0.05Nitrogen dioxide . . . . . . . . . . . . . . . . . . 0.005

Nonrecoverable waterd. . . . . . . . . . . . . . . 0.24Solid wastee. . . . . . . . . . . . . . . . . . . . . . . 0.70Land requirementsf. . . . . . . . . . . . . . . . . . 0.12aBaSed on ~~ earl Ier SPS cJeSlgrl assumes two satellites and rectennas are built

~~%~e~rlnlng, processing and fabricationCU. S totals In 1973dEor ~ropellant manufacture, launch pad COatln9, Coflstructlon.eFrOM dun-tin urn and steel processes.fFor ,eCtenna Sites as fraction of tc)td us. kind area

SOURCE Adapted from Env/ronmenta/ Assessment for the Sate///te PowerSystem Concept Development and Evaluation Program, DOE/ER-0069 August 1980


due to the other SPS technical systems. Studies needed to determine the incremental effect ofshould be conducted as the design parameters SPS on the environment relative to other elec-become more clear. Analysis would also be tricity generating faciIities.

HEALTH AND ECOLOGY

Human health and safety could be affectedby launch and space activities, mining, manu-facturing, and transport, and the constructionand operation of SPS receiving antennas andpowerl ines. These effects and the publ icconcern about them are likely to be mostpronounced closest to launch and receiver fa-cilities. Long-term exposure to low-level elec-tromagnetic radiation from SPS power trans-mission and distribution is a critical issue,involving potential health effects about whichvery Iittle is known. For SPS space workers, ex-posure to ionizing radiation is of the utmostconcern. Other important terrestrial impactsare shown in table 40. While the effects ofsome SPS activities such as mining and man-ufacturing are fairly conventional and couldbe routinely assessed, the uncertainties ofother health and ecological impacts, such asexposure to microwaves, are great. When ex-perimental data does exist it is rarely directlyapplicable to SPS. Furthermore, extrapolationfrom experimental animal to human healthand safety standards is tenuous and uncertainwithout a good theory on which to base the ex-trapolation. For other impacts, such as ex-posure to ionizing radiation, it is not clear ifexisting standards should apply to SPS. Morestringent standards can strongly influence SPSdesign, cost, and social acceptability. Ecologi-cal effects of SPS are also extremelyas little attention has been paid toplex area.

This second part of the chapter the health and ecosystem impacts

uncertainthis com-

will identifythat pres-

ently appear most significant. The first sectionwill address the bioeffects of terrestrial ac-tivities on the public, SPS workers and eco-systems. In the second section, the implica-tions for the health and safety of SPS space

workers will be discussed. With the exceptionof power-transmission effects, most of thehealth and safety risks described here pertainto the reference system only. There is notenough information on the personnel require-ments, industrial activities and environmentalimpacts to treat adequately the other tech-nical options. It is assumed that many of theeffects would be similar to those of the ref-erence system, varying only in intensity anddegree. It is important to note that some of theimpacts identified for the reference systemcould be minimized or avoided by workertraining, protection devices, or changes in thesystem design, but the effect of these measureson concept feasibility and cost need to beexamined in more detail.

Terrestrial Effects

The primary sources of potential health andecological effects are electromagnetic radia-tion from the power transmission and distribu-tion systems and noise and pollution fromlaunches, mining, manufacturing, and con-struction (see table 40). The risks to the ter-restrial worker are usually greater than to thegeneral public because of the increased fre-quency, duration, and intensity of occupa-tional exposure to certain hazards (althoughoccupational exposure could be more easilycontrolled by protective devices). Estimates ofSPS hazards have in many cases been extrapo-lated from other technologies, such as thespace shuttle. Risk analysis would improve asthe system design becomes more clear. How-ever, the major uncertainties associated withsome effects (e. g., electromagnetic radiation)rest in the state of biophysical knowledge andnot SPS specifications.


Table 40.—Terrestrial Health and Ecological Impacts

Microwaves● Effects of public and ecosystem exposure to low levels

uncertain● Occupational exposure higher; may require protective

clothing

Laser Light• Hazard to people and other living organisms directly ex-

posed to beam● Hazard to slow airplanes, birds, and insects f lying

through the beams

Reflected light (mirror system)● Ocular effects not expected to be significant; potential

hazard with binoculars not known. Psychological impacts on public, effects on the

photoperiod of plants and circadian rhythms, and naviga-tion of wildlife are unknown

Reflected light (from reference system)● Plants and animals would probably not be unduely af-

fected, but many effects are uncertain. The human eyecould be damaged if SPS reflected light were viewed fortoo long or with magnifying devices.

High-voltage transmission lines● Effects of public and ecosystem exposure to elec-

tromagnetic fields not well demonstrated but still uncer-tain (not unique to SPS)

Noise● Without preventative measures, construction noise from

certain machinery could exceed occupational standards;no significant public or ecosystem effect is anticipated

● Launch noise and sonic booms couId present problemsfor public and ecosystems. Workers would wear heavyprotective devices

Air Pollution• Without preventative measures, construction of recten-

nas couId violate standards for certain emissions such ashydrocarbons and particulate

● Mining, manufacturing, and transport emissions are ex-pected to be comparable to industrial and energy produc-ing processes (except coal)

● Launch effluents are not thought to exceed emissionsstandards unless ambient levels are high but studiesmust be refined

Ž Effects on ecosystems are unclear

Water Pollution● Construction and revegetation could deplete or con-

taminate local water, depending on site● Onsite facilities would be needed to treat polluted water

at launch site

Safety• Risks to public, workers, and ecosystems from the han-

dling and transport of toxic and explosive materials suchas rocket propellants

• Occupational risk of catastrophic explosion or launch ac-cident higher than that for public and ecosystems


Electromagnetic Radiation

Over the last few decades, the developmentand proliferation of technologies that utilizeelectromagnetic radiation has been astound-ingly rapid and widespread. However, there isa growing concern about the biological conse-quences of exposure to the radiant energythese devices employ. Terrestrial life as weknow it has evolved in response to a veryspecif ic spectral distr ibut ion, diurnal andseasonal cycle, and intensity of solar and ter-restrial radiation. It is possible that the alter-ation and enhancement of the ambient elec-tromagnetic environment brought about bymodern technologies could have a profoundimpact on biological ent i t ies and humanhealth.

SPS would increase the local levels of non-ionizing radiation (see fig. 39) in a few areas ofthe spectrum, e.g., microwaves, infrared laserlight, or reflected sunlight from the power-transmission system .54 The distribution ofpower from the receiving site via transmissionlines would also increase exposure to very lowfrequency or static field radiation at somelocations. Light reflected from the surfaces ofspace structures and vehicles would be visiblefrom Earth. Space workers involved in the con-struction and operation of SPS could also beexposed to high levels of nonionizing andionizing radiation in space.

MICROWAVES

There is not enough relevant data currentlyavailable to assess reliably the biological risksto humans, plants, and animals exposed to SPSmicrowaves. The data base that does exist is in-complete, often contradictory and usually notdirect ly appl icable to SPS.55 In part icular ,

5 4P Lorraln a n d D R C o r s o n , E/ectrornagnetic Fie/ds a n dWaves (San Francisco W.H Freeman, 1970)

5 sprel;m ,nar y fn v;ronmenta/ Assessment for the Sate//ite power

System [SPS) Revision 1, DOE/NASA report No DOE/E R-0036,January 1980


Figure 39.—The Electromagnetic-Photon Spectrum

Bolometer SparksLamps

Thermopile Hot bodies

Magnetron

Klystron

CrystalTravelling-wavetube

Electronic Electroniccircuits circuits

AC generators


there is a lack of information on the bioeffectsof chronic exposure to microwaves at low-power densities. Data is presently lacking onempirical dose-response relationships at theselow levels as well as on the theoretical mech-anisms of interaction between Iiving organismsand microwaves. Improved theory would facil-itate extrapolations (which are currently ten-uous and oversimplified) from experimentalanimal data to the prediction of human bio-effects.

This knowledge is also required for the quan-tification of SPS microwave risks, withoutwhich no useful assessment of the SPS micro-wave concepts can be made, If an SPS pro-gram is pursued, the study of microwave bioef-fects should receive top priority. Microwaveresearch and future microwave standardscould play a large role in determining thedesign and feasibility of SPS systems.

● SPS microwave risks. The SPS reference sys-tem microwave environment is illustrated ’infigure 40. Table 41 presents the public, occu-pational, and ecosystem exposure levels.Since the power densities emitted by thesolid-state system are lower as a function ofdistance from the rectenna center than thereference system, they will not be specifi-calIy addressed here.

No quantitative risk assessment for SPSworkers has been performed or is currentlypossible. Occupational exposures would needto be controlled by adequate protective cloth-ing and shielding, dosimeters (all of which arenot presently available), and possibly changesin system design.56 The extent of the necessaryprotection has yet to be determined. For oc-cupational exposure engendering the greatestrisks, (e. g., space workers and terrestrial per-sonnel working above the rectenna) it might benecessary to shut off or defocus the micro-

56prOgram A Ssessment Report, Statement of F;nd;ws, oP c It

wave beam if other protective measures proveinsufficient. Additional research would be re-quired to clar i fy the r isks and protect ivecriteria for short-term exposure. Possible syn-ergisms between the space environment (e. g.,ionizing radiation, weightlessness) and micro-waves must be explored as well as the plausi-bility of simultaneously shielding microwavesand ionizing radiation (see Space Environ-ment). It is also imperative that understandingof the long-term effects improve substantially(see below) before a reliable occupationalsafety threshold can be determined. In addi-tion, possible disparities between SPS micro-wave levels and occupational standards in thisand other countries (see table 42) should be ad-dressed, especially if SPS were to be a multi-national system. The effects on system costand feasibility of implementing protectivemeasures, complying with safety standards,and reducing the risks of long-term effects willneed to be analyzed.

Public and ecosystem exposure to SPS mi-crowaves is presently of greatest concern. Ithas been estimated that the 60 satellite refer-ence system would raise the ambient micro-wave level in the continental United States toa minimum of 10 -4 m W / c m2. 5 7A l t h o u g h n o tdirectly comparable, this level is two orders ofmagnitude greater than the median populationexposure to FM radiowaves.58 (Ambient micro-wave and radio frequency levels are inturn 106

times greater than natural levels of solar andterrestrial radiation.) It therefore appears thatthe general population and ecosystems wouldbe exposed to levels significantly higher thancurrent background microwave radiation.

The health risks of chronic exposure tomicrowaves, especially at these low levels (i. e.,

.“lbld

“R A Tell and E D Mantiply, “ P o p u l a t i o n E x p o s u r e t o V H F

and U H F Broadcast Radiation in the United States, ” Proc. IEEE,

68(1 ) 6-12, 1980

Ch. 8—Environment and Health . 211

Figure 40.—SPS Microwave Power-Density Characteristics at a Rectenna Site

0.02 mW/cm2

10 km13 kmat 35@

I Power denisity is

rectenna center

0.1 mW/cm2 at rectennasite exclusion boundary

SOURCE: Enwrorrnrenta/ Assessment for the Sate///te Power System Concept Development and Eva/uat/on Program, DOE/ER-0069,August 1980

Table 41 .—Characterization of Exposure to Reference System Microwaves—

Outside buffer zone Between 10-4 mW/cm 2 and 0.1 mw/cm2

Public——

Airplane flying through beam Less than 23 mW/cm2 (shielding)

Terrestrial workers Rectenna field Up to 23 mW/cm2 (may be higher if reflections

Space workersoccur)

Transmitting antenna Up to 2.2 W/cm2

Rectenna field:Ecosystems (plants, Under Outside buffer Less than 0.1 mW/cm2

wildlife, airborne rectennabiota) Inside buffer Between 0.1 mW/cm2 and 1.0 mW/cm2

Rectenna field: above Up to 23 mW/cm2

rectennaSOURCE: Environment/ Assessment for the Sate//ite Power System Concept Development and Eva/uat/on Program, DOE/ER-0069, August 1980.


Table 42.—Microwave Exposure Limits

Frequency (G Hz) Occupational (mW/cm2) Occupational duration Public (mW/cm2)

United Statesa . . . . . . . . . . . 0.01-100 10.0 No limit NoneU. S.S.R.b . . . . . . . . . . . . . . . . 0.3-300 0.01 Workshift 0.001Canada C. . . . . . . . . . . . . . . . . 1-300 5.0 8 hours 1.0Czechoslovakia . . . . . . . . . . 0.3-300 0.01 8 hours 0.0001Poland. . . . . . . . . . . . . . . . . . 0.3-300 0.2 10 hours 0.01Sweden d . . . . . . . . . . . . . . . . 0.3-300 1.0 8 hours 1.0

aThi~ is a ~uid~li”~ ~nlY and is “Ot ~nf~~C.abl~; the ~tarldard~ i“ the united Kingdom, German Federal Republic, Netherlands and France are similar to that Of the U.S.

guideline; ANSI will probably recommend 5 mWlcm2 as a new occupational exposure limit. ANSI and EPA are presently considering a new population limit.bo,l mwlcmz for rotating antennas.ccanada is proposing a 1 ITrw/cITIz limit at 10 tdHz to 1 GHz ‘requency.d5 mwlcm~ at o.01 to 0.3 GHz for 8 hours.

SOURCE: Adapted from L. David, A Study of Federal Microwave Standards, DOEINASA report No. DOEIER-1OO41-O2, August 1980.

less than 1.0 mW/cm2) cannot be analyzed withthe current data base. While appreciation forthe complexities of the interaction betweenmicrowaves and biological systems (see app.D) has grown in recent years, the state ofknowledge, particularly with respect to low-power microwaves, is immature and incom-plete; hence, no assessment for SPS can beconducted at this time. However, a DOE re-view of the existing scientific literature iden-tified the biological systems that might bemost susceptible to microwaves. 59 For the pub-lic and ecosystems outside of the rectenna,DOE tentatively concluded that effects on thereproductive systems would be small; risks tospecial populations (e. g., people taking medi-cation, children, older and pregnant people,etc. ) and effects on behavior would be uncer-tain and effects on the immune and bloodsystems appear unlikely. No cancer, devel-opment or growth effects would be expected.Again, however, the data base on low levelchronic exposure that supports these conclu-sions is incomplete and more research wouldbe required to satisfactorily assess potentialeffects.

For ecosystems (and SPS workers) at therectenna site, effects on physiology, behavior,development, reproduction and the thermo-regulatory, immune and blood systems mightbe possible .60 Of particular concern are theeffects on insects and birds that might fly

59A. R. Valentine, “Environmental Assessment Overview,” InThe Final Proceedings of the Solar Power Satellite Program Re-view, Apr 22-25, 1980, DOE/NASA report No Conf -800491, July1980.

‘“I bid

through the beam. Birds in flight are often neartheir thermal Iimit and exposure to micro-waves might result in thermal overloading. ”DOE has initiated three laboratory studies totest the effects on bees, birds, and smallanimals at SPS frequency and power densities.(See app. D.) While no significant effects havebeen observed to date, the research is far fromc o m p l e t e d .

● Research needs. A workshop organized bythe National Research Council (NRC) recent-ly identified the principal research prioritiesfor the bioeffects of exposure to low-levelSPS microwaves.63 These are listed in table43. Basical ly , three kinds of laboratorystudies are needed:

1

2

3.

animal laboratory experiments to estab-lish effects empirically as well as dose-response relationships;

studies of mechanisms of interaction atdifferent levels of biological organization(e.g., atoms, molecules, cells, organs); andimprovement of dosimetry, instrumenta-tion and models.

While limited resources might dictate thatthese studies be carried out only at the SPSreference system frequency and power densi-ties, it is clear that research at many fre-quencies and power densities would help toelucidate the fundamental mechanisms ofinteraction that allow extrapolations to bemade between frequencies, irradiance and

blEnvlronmental Assessment for the Satellite Power SystemConcept l)evelopment and Evaluation Program, op cit

‘Zlbld“Dodge, op cit


Table 43.—Research Needs To Help Reduce Uncertainties Concerning Public Health Effects Associated WithExposure to SPS Microwave Power Densities and Frequency

—Local or general thermal effects●

●

●

●

●

●

●

●

●

Long-term experiments at power densities< 0.1 mW/cm2

at whole body, organ, and organelle levels, testing for bio-logical endpoints such as alteration of enzyme reactionrates and cell membrane confirmational changes.Studies of basic physical interactions of electromagneticfields with molecular components of living tissue, to de-velop models of biological effects or phenomena. (For ex-ample, biophysical experiments are required to deter-mine the role of microwaves at SPS frequencies and in-tensities at the molecular level and their action on ionicconductivity. Any responses, biological, biochemical, orphysical, should be investigated from the point of view ofalteration of enzyme reaction rates, and cell membranephase transitions and confirmational changes.)Better dosimetry techniques for calculating and measur-ing (such as a probe that could be used within anorganism to measure in a nonperturbing way) internalfield patterns.

Interactions with drugs or other chemicalsRepeat selected experiments showing effects (includingthe potential of microwaves as a cocarcinogen), usingcarefully controlled dosimetry and statistical analysis.Develop and test hypotheses to explain effects.Long-term dose-response experiments at power den-sities around 0.1 mW/cm2 and with a larger number ofdrugs at whole body, organ, and organelle levels.

Immunological effectsRepeat selected Russian research at 1 to 500 mW/cm2

levels; repeat selected U.S. work to validate it.Mechanistic and molecular biological experimentation.Long-term studies, particularly autoimmune response.

— — . .

●

●

●

●

●

●

●

●

●

●

●

Effects on calcium ion efflum in brain tissueStudies to determine bioeffects using 2450 MHz as thecarrier frequency or studies to determine whether thepower density “windows” are carrier-frequency depend-ent.Studies to establish the interaction mechanism (the in-teraction site) of the modulated fields and ELF fields oncalcium ion efflux.Studies to determine whether the phenomenon will occurunder the modulation and power characteristics ex-pected of the SPS microwave beam.Studies to determine whether the calcium ion effluxphenomenon correlates with Russian and East Europeanfindings of neurological/behavioral decrements in peopleand animals exposed to low levels of microwaves.Experiments to determine whether other ions—sodium,potassium, magnesium–are similarly affected.

Effects on organized structuresStudies of changes in behavioral responses undersimulated SPS conditions, using behavioral tests (suchas time-based schedules of reinforcement) that are bothsensitive and reliable measures of such effects.Studies of long-term effects.Neurological and blood-brain barrier experiments at lowlevels.D e t e r m i n e t h e n e u r o l o g i c a l a n d physiologicalsignificance of behavioral responses.Molecular level studies on biological relaxation times.Consideration of long-term animal experiments at 2,450MHz to evaluate, if possible, whether there is any trendtoward life shortening in animals.

SOURCE: C H. Dodge, (rapporteur), Workshop on Mechanisms Under/y/ng Effects of Long-Term Low-Level, 2.450 MHZ Rad/at/on on Peep/e, organized by the NationalResearch Council, Committee on Satelllte Power Systems, Environmental Studies Board. National Academy of Sciences, July 15.17, 1980

species. It may also be possible that frequen-cies other than 2.45 GHz would be used forSPS. If a much different frequency were used,however, low-level microwave research wouldhave to be done at that frequency as well,because different frequencies cause differentresponses,

In addition to laboratory experiments, epi-demiological studies are also needed.64 It hasbeen argued that such studies are currently oflimited usefulness; they are very expensive, dif-ficult to accurately document (i.e., it is dif-ficult to determine the dose to which individ-uals are exposed) and may overlook importantbiological endpoints. 65 In addition they have

“Office of Science and Technology Policy, A Technica/ /7e-view of the Biological Effects of Non-lonlzlng Radiation, Wash-ington, D C , May 15, 1978

65paul Tyler, Armed Forces R a d i o l o g i c a l R e s e a r c h I n s t i t u t e ,

private communication, July 30, 1979

limited usefulness for exposure to low levels ofmicrowaves because the variability of the re-sponse is small and might be masked by othereffects. It is also not clear how many peoplewould need to be observed. Nonetheless acoordinated program of prospective epide-miology (as opposed to retrospective studiesthat rely on medical records many years afterexposures) and laboratory research is essentialto bridging the gap between biological effectsobserved in a laboratory animal and humanhealth standards.

Special attention must also be paid to ef-fects on ecosystems. To date, nearly all studieshave been conducted in a controlled labora-tory environment on a relatively few species.Virtually nothing is known about the effects ofmicrowaves on a complete ecosystem and nostudies have been performed that even ap-


preach the projected time scale of SPS opera-tion (i.e., 30 to 100 years). With respect to SPS,it must be determined if animals and airbornebiota would be attracted to the beam or wouldavoid it. What impact would microwaves haveon the navigational systems of birds and in-sects (as well as aquatic life for offshorerectennas)? What effect would exposure tomicrowaves have on the productivity of plantsand their susceptibility to drought? How wouldSPS affect the local food chain? The effects onmicro-organisms, such as bacteria, fungi, andalgae should be invest igated. 66

● Microwave standards. The biological con-sequences of exposure to low-level micro-waves are poorly understood because ofinadequate and sporadic support of micro-wave bioeffects research in general andbecause the bulk of research performed inthis country has focused on the bioeffects atlevels of 10 mW/cm 2 or greater. 67 This em-phasis stemmed from a belief that the onlybiologically significant damage from ex-posure to microwaves is due to heating. Infact, occupational guidelines developed inthe 1950’s through the Department of De-fense and its contractors in response to con-cerns about exposure of radar personnelwere based on biological injuries (e. g.,cataracts, burns) from acute exposure tomicrowaves on the order of 100 mW/cm2. Itwas concluded that humans could well tol-erate exposures to power densities 10 timessmalIer 68 (i. e., 10 mW/cm2) without sufferingserious or permanent damage. 69 This reason-ing was accepted by the American StandardsAssociation (now the American National

““0 P G a n d h i , “ Blohazarcf~ ot M i c r o w a v e Beams F r o m Prc~-

p o s e d Satel Ilte f]ower St~tlon~’, I n 1 ~ea /th /rnp/lcatlon$ of Newf nergy Tccfrno/oKlc\, W N Rom and V [ A r c h e r (eds ) ( A n n A r -

bor, MI( h Ann Arbor Scien{ e Publ l~her~ I n( , 1980)

“7P Tyler, “ O v e r v i e w o f Radlatlon Rt’sear( h Past, f’resent and

Future, ” I n B Io/oHIca / / ffec ( $ 0 f Nom Ion IZ Inx Racf Ia t Ion, P Tyler

(ecf ) (New York Academy of Science\, annal~, VOI 247, 1975)

““R Bower\, et al , ( ommun~catfon~ for a Mof)I/e $ocrety (Bev-erly H I I Is, Ca I If \age PLI bl I cat Ion\, 1978) ( Bel I [ aboratorles and

G e n e r a l F Iectrl[ rec ommencfeci () 1 nlW ( m’ and 1 () rnW/cm’re~pect Ively as maxr m um perm I\\ I ble expofure I Im Its )

““N H Steneck, H j C o o k , A j Vancfer, a n d C 1 Kane, “ T h e

Origln$ of U S Safety Standard\ tor Microwave Kadlatlon, ’$c/cnce, VOI 208, pp 1230-1237, j une 1 ], 1980

Standards Institute (ANSI) which in 1966recommended a maximum permissible ex-posure of 10 mW/cm2, averaged over any 6-minute period (1 O to 100 GHz).70 This ra-tionale also forms the basis of the currentU.S. occupational guideline (which in 1975was ruled advisory rather than a mandatorystandard”) as promulgated by the Occupa-t ional Safety and Health Administrat ion(OSHA) which adopted the ANSI recommen-dation in 1971. Presently, there is no officialrecommendation for general population ex-posures in this country.

The reasoning underlying the U.S. guidelineis currently in dispute and OSHA and ANSI areconsidering new recommendat ions. 72 73 T h econfIict centers around the assumption thatonly thermal effects result from exposure tomicrowaves. While it is generally acknowl-edged that exposure to microwaves of 10m W / c m 2 or greater will result in heating, theeffects and consequences of exposure to lowerpower densities are controversial. Experimentsdocumenting behavioral and neural changesand the enhancement of calcium efflux frombrain cells74 in particular have suggested theexistance of other effects at power densitiesbelow 1.0 mW/cm2. These phenomena arethought by some to result from direct interac-tions with the electromagnetic field ratherthan as an indirect consequence of heating.Some of the mechanisms that have been postu-lated for non ionizing radiation include:

1. distortion of the shapes of individualmolecuIes or rearrangement of a group ofmolecules that might transiently or per-

——..‘“L David, A Study of Federal Microwave Standards, D O E I

NASA report No DO E/E R-10041-02, August 19807 ‘General Accounting Office, Efforts by the Errvironrnenta/ Pro-

tection Agency to Protect the Public From Environmental Non-Ion\zrng Radiation Exposures, Washington, D C , Mar 29, 1978

‘ A W (;uy, “Non-l onlzlng Radiation. Doslmetry and lnterac-tlon, ” I n Non-Ionizing Radiation, proceedings of a Toplca I Sym-posium, Nov 26-28, 1979, The American Conference of Govern-mental I ndustrlal Hyglenlsts, I nc , 1980

“‘Z R (;laser, “Basis for the NIOSH Radiofrequency and Mi-

crowave Rad Iatlon Criterl a Document, ” In Non-Ioniz ing Radia-tion. proceedings of a Topical Symposium, Nov 26-28, 1979, TheAmerican (-onference of Governmental I ndustrlal Hyglen ists,Int , 1980

“Dodge, Op clt


manently alter the function and replica-tion process of a biological unit;75

2. reorientation of dipole molecules in themicrowave field and polarization of mol-

ecules that control membrane perme-abiIity; 76

3. biological electromagnetic interference inwhich the microwave field disrupts or en-hances the transfer of biological informa-t ion in the fo rm o f e lec t romagnet icenergy between molecuIes and celIs; 77

and4. field receptor interactions where neural

tissue acts as a receptor of weak fields. 78

The discussion of low- leve l e f fec ts i shampered by the experimental difficulties ofisolating the various possible mechanisms.Most U.S. microwave experts acknowledge theneed for research on low-level effects, but re-main skeptical about their biological signifi-cance, especially at the proposed SPS singlefrequency of continuous radiation.

The controversy over low-level effects hasbeen fueled by the disparity between U.S. andU.S.S.R. research and exposure standards (seetable 14)—the Soviet standard is three ordersof magnitude lower than the U.S. guideline.Some U.S. authors have attributed the differ-ent standards to dissimilar research philoso-phies. 79 For example, microwave studiesthought most valid by U.S. scientists are thoseperformed in a controlled laboratory environ-ment, whereas Soviet researchers rely on clin-ical and “subjective” data as well. 80 In fact,based on the complaints of radar personnel,

“K D Straub, “Molecular Absorption of Non-Ionizing Radia-tion in Biological Systems” In The Ph yslca / Basis of Electromag-netic Interactions With Bio/ogica / Systems: Proceedings of aWorkshop, University of Maryland, june 15-17, 1977, L Taylorand A Cheung (eds ), US DHEW, 1978, report No [FDA) 78-8055,Washington, D C , April 1978

“A S Pressman, E/ectromagnet~c F)e/ds and Life (New YorkPlenum Press, 1970)

“lbld“D R Justesen, et al , “Workshop on Radiation: Scientific,

Technological, and Soclologlcal Implications of Research andon Biological Effects of Radio-Frequency E Iectromagnetic Radi-ations, ” In Proceedings of the 1978 Conference on U.S. TechnicalPo/icy (New York. IEEE, 1979)

“W C Milroy and S M Michelson, “The Microwave Contro-versy, ” /nternationa/ journa/ of Envlronmenta/ Studies, VOI 4, p

123, 1973‘“D R J ustesen, Veterans’ Admlnlstratlon, private communi-

cation, J u Iy 16, 1979

“microwave sickness” has been isolated as adistinct occupational disease in the U. S. S. R.”It has also been argued that the Soviet ex-posure levels are based on the occurrence of abiological effect whereas the U.S. guidelinereflects levels of known biological damage(with a safety margin). ” Moreover, it has beenclaimed that the Soviet standard has been setwithout regard to the practical feasibility ofmeeting such low levels. It is further arguedthat in any case the standards are not en-forced, especial ly in the mi l i tary sector ,a l though this would be di f f icul t to sub-stantiate.

For many years the flow of information be-tween East European and Western researcherswas restricted. Translation problems some-times also contributed to misunderstandings.83

This situation has improved considerably, andattempts are being made in the United Statesto replicate many of the low-level experimentsperformed in other countries (although theUnited States still has not sponsored anyclinical studies). Western literature is alsobeginning to acknowledge the possibility ofbehavioral response and selective sensitivityof organs to low levels .84 Partly for thesereasons, it is anticipated that new ANSI guide-lines will be established that are more stringentthan the present exposure levels (see fig. 41). Atthe SPS frequency of 2.45 GHZ, the maximumoccupational exposure that is now being con-sidered is 5 mW/cm2. * EPA is also considering— .—

“C H Dodge and Z R Glaser, “Biomedical Aspects of RadioFrequency and Microwave Radlatlon A Review of Selected Sovi-et, East F u ropean, and Western References” I n Bio/ogica/ Effectsof E Iectromagnetic Waves: .Se/ected Papers of the USNC/URSlAnnual/ Meeting, L L Johnson and M Shore (eds ), Boulder,COIO , October 1975, USDHEW, (report No (FDA) 77-8010/8011),Washington, D C 1976

“[1 Mlchaelson, In Symposium on the Bio/ogica/ Effects andHealth /mp/lcations of Microwave Radiation, S Cleary (ed ),RI( hn~ond, 1969, USDHEW, report No BRH/DBE 70-2, 1970, pp76-81

“‘F’rzemyslaw Czerskl, Department of Genetics, National Re-sear( h I nstltute of Mother and C h ild (Poland), private commu n i-catlon Sept 5, 1979

“’C H Dodge and Z R Claser, “Trends In Non-ionizing Elec-tromdgnetlc Radlatlon Bioeffects Research and Related Occu-pational Health Aspects,” Iournal of Microwave Power, VOI 12,No ~ 1977, Pp 319-334

*Thl\ level has been criticized by the National ResourcesDefense Councrl as being arbitrary and not found with anyrecognition of possible nonthermal effects, see ch, 9, Pub/ic/5 $11(?’>


Figure 41 .—Comparison of Exposure Standards

1 01

, 0 0

1

SOURCE: A. W. Guy, “Nonionizing Radiation: Dosimetry and Interaction,” inNonionizing I?adiationj Proceedings of a Topical Symposium, Nov.

26-28, 1979, The American Conference of Governmental IndustrialHygienists, Inc., 1980.

the development of exposure guidelines forthe general population, although it does nothave the jurisdictional authority to enforcestandards. It is conceivable that future publicstandards could be established at 1.0 mW/cm2

or below.8 5 The impact of more str ingentstandards on SPS design and concept viabilityshould be addressed.

Agencies. At present, the study of the bioef-fects of nonionizing radiation falls under thejurisdiction of 13 Federal agencies.86 The allo-cation of funds (currently about $15 millionper year) is shown in figure 42. The agenciesprimarily responsible for regulation and theestablishment of microwave guidelines 87 i n -

*’David, op. cit.8bF;fth Report on “program for Contro/ of Electromagnetic po/-

Iution of the Environment: The Assessment of Biological Hazardsof Nonionizing Electromagnetic Radiation, ” NT I A report No79-19, U.S. Department of Commerce, March 1979.

87 David, op cit

Figure 42.— Program Funding

FY-77 FY-78$7.6 M $10.1 M

SOURCE: Fifth Report on “Program for Contro/ of Electromagnetic Po//ution ofthe Environment: The Assessment of Biological Hazards of Nonion-Izmg Electromagnetic Radiation, ” NTIA report No. 79-19, U.S. Depart-ment of Commerce, March 1979.

elude the Department of Health and HumanServices (the Bureau of Radiological Health/Food and Drug Administration, for example,sets emission standards for electronic productssuch as microwave ovens); the Department ofLabor (which sets occupational guidelines);and EPA (which sets environment guidelinesfor other Federal agencies).

The Federal effort has been coordinated atvarious times by other Federal agencies, but aclear , dedicated, wel l managed and ade-quately funded national program in micro-wave bioeffects research is currently lacking.To some extent, the ineffectiveness of theagencies responsible for the management ofthe Federal program is due to lack of control


over the allocation of research funds .88 It isalso often the case that within each of theresearch and regulatory agencies, microwaveresearch receives low priority on the agency’sa g e n d a . j u r i s d i c t i o n a l a m b i g u i t i e s h a v ecaused some agencies to take a limited ap-proach to research and protect ion. Mult i -agency effort has also made public partici-pation and education difficult.

Often, the most cohesive and vigorous re-search and evaluation of microwave bioeffectstake place in conjunction with one particulartechnology such as a radar facility. This is notalways the best arrangement since in the past,user agencies with vested interests have oftenbeen responsible for the assessment of healthand environmental impacts. Moreover, funda-mental research is needed in order to elucidatethe mechanisms of interaction; technoiogy-specific research is helpful but usually does

68 Tyler, op cit

not contribute significantly to basic under-standing. In addition, long-term continuousstudies are needed and project-specific re-search is sporadic and unpredictable.

Nonetheless, unless the Federal research ef-fort is consolidated into fewer agencies andgiven greater support, it is likely that an SPSprogram would be required to sponsor micro-wave bioeffects studies as it did in the DOEassessment. If the current climate continues,this research would not only gather informa-tion specifically relevant to SPS, but wouldprobably be quite fundamental in nature. If amicrowave SPS program is pursued, the devel-opment of SPS would entail the involvementof the Federal agencies shown in table 4 4 .State agencies might also be affected.

Conclusion. DOE-sponsored microwavestudies stimulated thinking about the design ofmicrowave bioeffects experiments, tended toclarify research needs and obstacles and con-

Table 44.—SPS Development

SPS development phase Microwave aspect Agency involvementBasic research . . . . . . . . . . . . . . . . . . .

Applied research . . . . . . . . . . . . . . . . .

Exploratory development . . . . . . . . . .

Technology development . . . . . . . . . .

Engineering development. . . . . . . . . .Demonstration . . . . . . . . . . . . . . . . . . .

Commercialization. . . . . . . . . . . . . . . .

Production . . . . . . . . . . . . . . . . . . . . .

Operations . . . . . . . . . . . . . . . . . . . . .

Env i ronmenta l and pub l ic hea l th e f fec ts --— —— . . .—. . .. —- . . . . - .

evaluation MPTS technologyConduct experiments and further define

health and safety risks of MPTS topublic, the environment and SPSworkers

Preliminary standards developmentradiation exposure standardsoccupational health and safetystandards development

Final standards for MPTS chosenoccupational health and safetystandards finalization

Preparation of environmental impactGuidelines for health and safety

(worker) enforcementGuidelines for public health and safety

environmental impact statementsReview guidelines for worker

health and safetyReview guidelines for public health

and safetyEnforcement of guidelines for

worker health and safetyEnforcement of regulations for

public health and safetyEnforcement of guidelines for worker

health and safetyEnforcement of guidelines for public

health and safety

DOE, EPA, HEW/FDA, NASA

DOE, NASA, HEW/FDA, Department ofLabor/OSHA EPA

HEW/FDA, DO E/EV, EPA, HEW/FDA,Bureau of Radiological Health, Department

of Labor/OSHA

HEW/FDA, DOE/EV, EPA, DOL/OSHA

Council on Environmental QualityDepartment of Labor/OSHA

HEW/FDA-Bureau of Radiological Health,EPA, Council on Environmental Quality

Department of Labor/OSHA

HEW/FDA, EPA


EPA


EPA

SOURCE: L. David, A Study of Federa/ M/crowave Standards, DOE/NASA report No DOE/ER-10041 .02, August 1980.

83-316 0 - 81 - 15


tributed to an increased study capability.While the results of these studies are useful,the time and resource constraints of the SPSassessment program precluded a thorough re-search agenda; in particular, no studies onlong-term exposure to low levels of micro-waves could be initiated and little more couldbe done to improve our theoretical under-standing. In spite of the general acknowl-edgment by the microwave community of theneed for studies of chronic, low-level exposure,practically no such studies are underway orplanned. Clearly, if many of the fundamentalquestions about the bioeffects of microwavesare to be resolved within the next one or twodecades, a more comprehensive, dedicated na-tional research program will be needed.

LASER LIGHT

The biological risks associated with the lasersystem have been assessed only to a very Iim-ited degree. The power density of the focusedlaser system beam would be sufficiently greatto incinerate biological matter.”’ Safety meas-ures (such as a perimeter fence and pilot beamsystem) would have to be devised in order toavoid beam wandering and the direct exposureof the nearby public and ecosystems. Less easyto protect would be birds and insects flyingthrough the beam; without some sort of warn-ing device they wouId be incinerated.90 It is notknown if air-borne biota would be aware of thebeam, and if so whether they would be at-tracted to or avoid it. Siting studies shouldconsider migratory flyways and local birdpopulations.

It has been suggested that aircraft be re-stricted from the power beam area. 91 While itis not expected that jets and their passengerswould suffer any damage in traversing thebeam due to their high speed and infrared re-flectivity, slower flying, less reflective aircraftcould be affected. More important, laser lightspecularly reflected from an airplane wouldpresent an ocular hazard to the public. 92 Aradar warning system might be devised to de-

“’Beverly, op clt‘OWalbrldge, op clt9’ Beverly, op clt92 Walbrldge, op clt

focus the laser beam if a plane did happen tofly through it.

The primary risk to the public and nearbyecosystems outside of the direct beam wouIdbe due to laser light scattered from clouds,dust and the receptor site. This “spill over” oflaser power (less than 1 percent) would neces-sitate establishing a buffer zone surrounded byan opaque, talI fence.93 As shown in figure 33,it has been estimated that a protection radiusof 300 to 800 m wouId be required in order tolimit public exposure at the perimeter to 10m W/cm a recommended maximum whole-body irradiance limit.94 More research wouldbe needed to verify this exposure guidelineand to investigate the effects of chronic ex-posure to low level laser radiation. For visibleIaser beams, the risk of ocular damage couldbe increased at the receiving site if magnifyingdevices were used. Prolonged occupational ex-posure at infrared power densities greater than10 mW/cm2 would be of particular concern,especially for the cornea. Workers at receivingsites wouId probably be required to wear pro-tective clothing and eye goggles.

Hazards outside of the site have not beenassessed. It is unlikely that wildlife or vegeta-tion at the receptor site would survive. 95 T h eetfects of the low level laser Iight on eco-systems outside of the receptor area are notknown It is possible that certain infrared sen-sitive Insects would be attracted to the laserbeam, but this requires further study .9’

The bulk of research on the biological ef-fects of lasers is not directly applicable to theinfrared lasers that have been suggested forSPS Most studies have concentrated on theeffects on the eyes and skin of visible and nearinfrared lasers in a puIsed mode. The standardsthat have been promulgated pertain predomi-nantly to short-term occupational exposure to

———‘ ‘Beverly, op clt‘“[3 H Sllney, K W Vorpahl, a n d D C Wlnburn, “Envlron-

nlenta I H ea Ith Hazards From H lgh-Powered I nfra red Laser De-V I <-e $ ‘ ‘ \rch Envlronmenta/ Ffea/th, VOI 30, April 1975, pp174170

“‘W~lhrldge, op clt

““lhl(i


lasers operating in a controlled indoor environ-ment such as a laboratory or medical facility.Few studies have examined the effects ofchronic exposure at SPS-like power densitiesand under SPS environmental conditions. Asummary of known effects on the skin andeyes is presented in appendix D.

REFLECTED LIGHT FROM THE MIRROR SYSTEM

The light reflected by the mirror system toEarth would be visible at night as a generalglow at up to 150 km from the receiving site. ”The potential health impact of most concern isocular damage from either the scattered lightor from direct exposure to reflected light asthe mirror image sweeps across the Earth dur-ing orientation maneuvers. Since the CoIIectiveintensity of all the mirrors at one site would beequal to that present in the desert at noon, itappears that the intensity of Iight would be toolow to be of danger to the observer. One in-vestigation revealed that under the worst con-ditions (i.e., staring, no blinking) it would besafe to view the mirrors directly for at least 2.4minutes. ” No information is available regard-ing the ocular effect produced when an indi-vidual views the mirrors with a binocular ortelescope. The psychological effects of a “24-hour day” or aIterations of the sky near thesites also needs to be studied.

The ecological impacts have not been as-sessed. It is known that the polarization, fre-quency and intensity of light as well as thepercentage of daylight hours influence thebehavior, navigation, and lifecycle of manyspecies of wi ldl i fe and vegetat ion; manyspecies have inherent biological clocks or cir-cadian rhythms that are triggered by the diur-nal and seasonal var iat ions of sunl ight .9 9

However, ecosystems in the area surroundingthe receiver site would be exposed to lowlevels of incremental sunlight and so it doesnot appear Iikely that significant biological ef-

97 Billman, private communlcatlon, op clt‘*M T Hyson, “Sunllght ReflectIons From a Solar Power Satel-

lite or S O L A R E S Mirrors Should Not Harm the Eyes, ” In The Flr-ra/Proceeding of the Solar Power .$atellite Program Review, Apr22-25, 1980, DOE/NASA report No Conf -800491, July 1980

“McGraw-Hi/l Encyclopedia of Science and Technology, V O I10 (New York McGraw-Hill Book Co , 1977)

fects would occur. Nonetheless, researchshould be conducted in this area. The effectsof changing the night sky also need to bestudied for ecosystems both near and distantfrom the site. Ecosystems could also be in-directly affected by weather modification in-duced by the mirror system.

LIGHT REFLECTED FROM REFERENCE SYSTEM

The transportation vehicles, constructionand staging bases, and the satellite structure ofthe orbit ing satel l i te systems wi l l ref lectsunlight, discernible on Earth. Some specularreflections from reference system componentsmay be exceptionally bright due to their largesize, low altitude, and reflectivity. 1oo M o s tspecular reflection would be restricted tosmall, fast moving spots or “glints” as thestructures and vehicles change orientation.The worst cases, which may exceed acceptablelimits, occur for reflections from the solarpanels of the OTVS while in LEO, and the backof the solar panels in CEO. Diffuse reflections,brighter than most stellar sources would makethe LEO OTV staging base visible during theday It may be possible to reduce most of thesereflections by controlIing the orientation, sur-face curvatures, solar panel alignment and sur-face quality of the vehicles and structures.Reflection of visible light from the compo-nents of other SPS technical options may besimilar to the reference system depending onthe orbit and size of transportation vehiclesand space structures.

The effects on the public and ecosystemshave yet to be evaluated in depth. One studyfound that the reflections from the referencesystem would be bright but not dangerous tothe human eye101 unless viewed for too long orwith a magnifying device. Studies would befurther needed to evaluate the ground illu-mination in terms of human exposure limitsand to explore any possible psychological ef-fects While DOE has tentatively concludedthat plants and animals would not be unduly

“’(’D [ Llemohn, D H Tlngey, and B R Sperber, “Character-izat lorl of Reflected L Ight From the Space Power System, ” In TheFindl Proceed)ngb of the Solar Power Satellite Program Revfew,Apr IL 25, 1980, DO E/NAsA report No Conf -800491, ) uly 1980

‘‘“ I+v\on, op cIt


affected by the reflected light, ecosystem ef-fects are largely uncertain. More researchwould be needed to investigate how altera-tions of the day and night sky could influencebehavior, navigation, and Iifecycles of wildlifeand vegetation.

Noise

Noise is generated during rocket launchesand the construction of receiving stations.With respect to the latter, the highest n o i s e

levels would resul t f rom heavy equipmentused to prepare the site and build the supportstructure. The DOE prototype siting study con-cluded that it would be unlikely that signifi-cant noise-related impacts on the public andmost animals located 2 km or more from theprototype construction site would occur. ’02

For some machinery, occupat ional noisestandards would be exceeded. Mit igat ionmeasures include ear protection devices, muf-flers for machinery, and special insulation infactories.

Very high noise levels would be associatedwith launch vehicles during ascent and reentry.Table 45 presents the estimated noise pro-duced by the HLLV. Table 46 is exhibited forcomparison. A preliminary assessment indi-cates that the OHSA standard of 115 db(A)would be exceeded within 1,500 m of thelaunch pad, and the EPA guideline violatedwithin 3,000 m. 103 Using the Kennedy SpaceCenter as a prototype launch site, the study

“)’ Protot ype Envlronmenta/ Assessment of the /mpacts of $Irlrrgand Construct~ng a Sate//fte Power $ y~rem ( SP$) Ground /7ecelv-Irrg Stat Ion (C RS), op c It

“’JEnvlronmenta/ Assessment for the \ate//lte Power SystemConcept Development and Eva/uat/on Pro#ram, op clt

Table 46.—Representative Noise LevelsDue to Various Sources

Source or description of noise - Noise level (db)Threshold of-pain . . . . . . . . . . . . . . . . . . . . . . 120Riveter 95Elevated train” . . . . . . . . . . .. . . . . . . . . . .. . . . . . . . . . . 90Busy street traffic. . . . . . . . . . . . . . . . . . . . . 70Ordinary conversation . . . . . . . . . . . . . . . . . . 65Quiet automobile . . . . . . . . . . . . . . . . . . . . . . 50Quiet radio in home . . . . . . . . . . . . . . . . . . . . 40Average whisper . . . . . . . . . . . . . . . . . . . . . 20Rustle of leaves. . . . . . . . . . . . . . . . . . . . . . . 10Threshold of hearing . . . . . . . . . . . . . . . . . . . 0

— —. —SOURCE Errv/ronrnenfa/ Assessment for tire Satelllte Power System Concepf

Development and Evaluatlorr Program, DO EIER-0069, August 1980

concluded that launch noise wouId not inter-fere significantly with speech (interruption for2 minutes at 30 km twice a day), but that inter-ference with sleep could occur 30 km from thesite Table 47 presents an estimate of thenumber of people annoyed by the noise as afunction of distance. Sonic booms would alsobe generated; pressure levels are shown forHLLVs and PLVs in table 48. The HLLV sonicbooms would not cause injury but would in-voke gross body movements and might inter-fere with sleep. It has been suggested that thetrajectories of launch vehicles should avoidpopulation areas.

The effects of noise on wildlife include star-tle responses and disruption of diurnal andreproductive cycles that could be particularlysignificant in endangered species habitats. Ithas been suggested that wildlife would adaptto the noise, but this is not clear. ’04 While thenoise generated by the space shuttle is not ex-pected to be serious, the effects of HLLVswouId be greater because of the increased fre-— — . .

“ ‘Ibid

Table 45.— Estimated Sound Levels of HLLV Launch Noise——

Distance from launch pad.

Sound level and duration 300 m 1,500 m 3,000 m 9,000 m 30,000 mOASPL a (dB) . . . . . . . . . . . . . . . . . . . . 149 136 130 120 109A-level b [db(A)] . . . . . . . . . . . . . . . . . . . 130 114 105 89 72Duration(s) . . . . . . . . . . . . . . . . . . . . . . 12 42 54 77 77

aOASPL: overall sound pressure level expressed In decibels (db) above the level corresponding to a reference pressure of 20 pa (pa= Pascal = 1 N/mz)bA-ievei: Weighted average sound level over the frequency spectrum In accordance with the Performance of the human ear

SOURCE: Env/ronmenta/ Assessment for the Sate//lte Power System Concept Deve/opmerrf dftd Eva/uat/on Program, DOE/ER-0069, August 1980


Table 47.–Community Reaction to HLLVLaunch Noise

Percent of people highlyDistance from launch point (m) annoyed a

300 . . . . . . . . . . . . . . . . . 901,500 . . . . . . . . . . . . . . . . . . . . . 453,000 . . . . . . . . . . . . . . . . 249,000 . . . . . . . . . . . . . . . . . . . . . 5

30,000 . . . . . . . . . . . . . . . . . . . . . 1

aBa~edon a24.hraverage of thenowe

SOURCE Env/ronmenta/ Assessment for the Sate///(e Power System ConceptDeve/opmentand Eva/uat/on Program DOE/ER-0069, August 1980

Table 48.—Sonic Boom Summary (Pa)———

Vehicle Launch Reentry

H L L V b o o s t e r . ‘1 ,200 190HLLV orbiter . . . . . . . — 140PLV booster. . . . . . . . 770 140PLV orbiter. . . . . . . . . — 70

SOURCE Env/ronmenfa/ Assessment–for the Sate///te Power System ConceptDeve/opmenf and Eva/uat/on Program DOE/ER-0069, August 1980

quency and level of noise, due especially tosonic booms.

Terrestrial workers would be exposed tonoise levels higher than the general public andwouId require hearing protection. 105 Possiblehearing damage and pyschological effectsshould be studied in Iight of the unprece-dented frequency and size of launches.

Other Risks

Quantitative studies are needed to deter-mine SPS impacts on air and water quality andthe generation of solid wastes. It is currentlyassumed that these impacts would be compar-able to typical industries and powerplants (ex-cept coal) and that unusually high risks wouldnot be encountered by the public and terres-trial workers that could not be minimized orcorrected. ‘)() The effects on ecosystems areless certain.

DOE has concluded that acid rain from theSPS launch ground cloud would be localized,temporary and minimal. Because of the conse-quences of ozone depletion, i.e., a l-percent

“)’lbld“’hlbld

decrease in ozone corresponds to a 2-percentincrease in biological harmful ul travioletradiation that reaches the Earth, 107 the effectsof SPS on the ozone layer has been studied.preliminary analysis concludes that the changein ozone brought about by SPS launch ef f lu-ents would be negligible, but further study isrequ i red. 108

The deployment of SPS would also requirethe mining, production, and transport of cer-tain toxic materials. Some toxic materials suchas hydrocarbons could also be released fromfuel burning in the launch and recovery ofspace vehicles. Rocket propellants such as liq-u id hydrogen are of special concern becausethey are toxic, flammable, and explosive. 109 Aspill of liquid oxygen would adversely affectlocal ecosystems. However, no information isavailable to quantify the exposure or risk tothe public, workers or ecosystems. An incre-mental increase in the risk of catastrophic ex-plosions or fire is thought possible, especiallybecause of the large amount of fuels involved;the occupational risk, of course, being consid-e rab ly h igher than tha t fo r the pub l i c .Launch and recovery accidents are not likelyto have any more impact on the public thanconventional aircraft accidents, although ithas been suggested that flight trajectoriesavoid populated areas. The noise and shockwaves from a catastrophic explosion of anHLLV could possibly blow out windows anddoors in buildings up to 15 km from the launchpad ‘‘

Space Environment

Many space workers would be needed toconstruct and maintain an SPS system. Thereference design, for example, requires 18,000person-years in space; 112 workers would serveten 90-day tours over 5 years. Other SPS de-signs may have different personnel require-ments, but they will not be specifically ad-

“)’} Hamer, “Ozone Controversy, ” Editor/a/ Research Reports,VOI 1, No 11, 1976

‘ ‘“l bl[i““l bld‘ “)1 bid‘ ‘ ‘ Ibid‘‘ ‘Program Assessment Report, Statement of Findings, op clt


dressed here. The health effects of the spaceenvironment are potentially serious, but highlyuncertain; experience with people in space islimited to a few highly trained astronauts wholived mostly in LEO for a maximum of a fewmonths. 113 NASA’s current ground-based pro-gram as well as future activities with the spaceshuttle and space operations center will yieldinformation relevant to SPS space workerhealth and safety. DOE does not consider thepotential health effects an obstacle to con-tinued planning and development of SPS, 114

but if this and other space projects are to be

considered, the health and safety of space per-sonnel should be a high-priority research task,

The principal health and safety risks of thespace segment of SPS are illustrated in figure43. Effects on the general health and safety ofspace workers such as accelerat ion andweightlessness are discussed in appendix D.

The most serious potential health risk of thespace environment is exposure to ionizing radi-ation. The types of radiation found in thedifferent SPS orbits are listed in table 49.Exposure to radiation in CEO and in transitbetween LEO and CEO are of most concernbecause, under the reference system scenario,workers spend approximately 91 percent of

Figure 43.— Factors Pertinent to Space Worker Health and Safety

Space structurecharging High voltages

Electric and \ / Construction

Transport ce debrisaccidents eoroids

accidents

Constructionaccidents

o

Space debris

Transport accidentsL i f e pfailure

transport accidentsacceleration/deceleration

SOURCE Program Assessment Report Statement of FindingsDOE/E R-0085 November 1980

Satelltte Power Systems ;oncept Development and Evaluation Program, DOE/NASA report No


Table 49.—Types of Radiation Found in theDifferent SPS Orbits

GEO● Radiation belts—Electrons—dominant when shielding is less than

3gm/cm2 aluminum—Bremsstrahlung —produced by electron interactions with

shielding—dominant when shielding is greater than3 gm/cm2 aluminum

—Protons—low energy—stopped by minimal shielding● Galactic cosmic rays—Protons—Helium ions—High-energy, heavy ions● Solar particle events— i.e., particles accelerated to high

energies during a solar f I are—Protons—Heavy nuclei

Travel Between Orbits• Radiation belts—Bremsstrahlung radiation produced by electrons—Protons

LEO. South Atlantic Anomaly—Protons—Electrons—low energy—stopped by minimal shielding

SOURCE: Margaret R. White, Lawrence Berkeley Laboratory, private com-munication, Feb. 12, 1981

their time in the higher orbit where the radia-tion environment is the most severe. 115 In GEO,except under the unusual circumstance of alarge solar flare, the major part of the radia-tion dose in the reference system would be dueto bremsstrahlung produced by the interactionof high-energy electrons with the shieldingmaterial. The biological effects of this kind ofradiation are reasonably well understood, andinnovative shielding might reduce this dose.However, radiat ion from the high-energy,heavy ions (HZE) in galactic cosmic rays can-not be stopped by conventional shielding andtheir biological effects are current ly verypoorly understood. From theoret ical con-siderations and preliminary experiments it ap-pears that they may be much more effective incausing biological damage than other types ofionizing particles. Thus, though they con-tribute a small fraction of the total radiationdose in the reference system, they are of majorconcern with regard to the health of spaceworkers.116

‘ “ionizing Radiation Risks to Satellite Power Systems [SPS)Workers, LBL-9866, November 1980, advance copy

1“M R White, Environmental Assessment for the SatellitePower System, Non-Microwave Health and Ecological Effects,DOE, in press (1981)

Estimates of the radiation dose for exposedSPS space workers are uncertain. Few measure-ments have been made of the radiation fIux inG E O .117 It is also difficult to quantify the radi-ation levels at any one time because solarstorms that significantly increase the levels arecurrently impossible to predict. Moreover,there is considerable controversy over themodels that are used to estimate the amountof energy absorbed in the human body as wellas the biological consequences of the ab-sorbed radiation.118 The most significant long-term effect of ionizing radiation is cancer.Cancer risk depends on a number of factors in-cluding the total I-fetime dose-equivalent;dose rate; duration of exposure; and the age,sex, and susceptibiIity o f t h e e x p o s e dperson. 9

DOE has estimated that space workers forthe SPS reference design (which includes mod-est shielding— 3 g/cm2 aluminum for habitatand work stations and 20 to 30 g/cm2 for thestorm cellar, used during solar particle events)would receive 40 reins per 90-day tour or 400reins for the planned 10 tours.120 This estimatecould be inaccurate (probably too high) by afactor of 5 or 10.2’ However, the biological im-pacts could actually be higher than this dosewouId indicate if HZE bioeffects are taken intoaccount and/or a solar particle event occurs. I nspite of the large uncertainties, it is almost cer-

tain that reference system exposure w o u l d e x -ceed current Iimits for radiation workers asrecommended by the National Council on Ra-diation Protection and the International Com-mission on Radiological Protection.122 Forcomparison, the general popuIation receivesabout 0.1 rem/year on the average;123 occupa-

‘ 7M~rgaret R White, L a w r e n c e B e r k e l e y L a b o r a t o r y , p r i v a t e

communlcatlon, Feb 12, 1981

‘‘ “Program Assessment Report, Statement of Findings, op. c It‘ “1 1 Lyman, “Hazards to Workers From Ionizing Radiation

In the S PS E nvlronment, ” in The Final Proceeding of the SolarPower $ate//ite Program Review, Apr 22-25, 1980, DOE/NASAreport No Conf -800491, July 1980

‘J{)lonlzlng Radiation Risks to Sate//lte Power .Systems (SPS)WorLer>r op clt

‘” Program Assessment Report, Statement of Findings, op clt‘‘Zlbld‘‘ ‘Committee on the Blologlcal Effects of Ionlzlng Radiation,

The F f fects on Populations of Exposure to Low Leve/s of IonizingRacflat/on (BE/R ///), National Academy of Sciences, 1980,tvpesc rlpt edltlon


tional exposure l imits ( for blood termingorgans) are 3 reins for 90 days and 5 reins over1 y e a r ;1 2 4 and the NAS maximum recom-mended exposure limit (for bone marrow) forastronauts is 35 reins for 90 days, 75 reins overl-year period and 400 reins for Iife.125 If spaceworker careers were 5 years, with 90 days inspace alternated with 90 days on Earth, itw o u l d b e e x p e c t e d t h a t f o r e a c h 1 0 , 0 0 0workers in space, between 320 to 2,000 addi-tional cancer deaths in excess of normal can-cer mortality would occur.126 An issue criticalto SPS design and economics is whether theradiation standards developed for astronautsshould be applied to SPS workers.127

Risks could be reduced in a number of ways.For example, the time per tour and the numberof tours per worker could be decreased. Ro-bots and teleoperation could be used to re-duce the number of people required in space.It is also essential that accurate, quick andrugged dosimeters be developed that monitorthe real-time radiation flux and energy levelsto which each indiv idual is exposed.128 i n -struments would also have to be developed towarn personnel in GEO of solar storms or otherunforeseen high radiation events so that theycan move to shelters. Considerable improve-ments in dosimeter technology are neededsince present devices are not very accurateand take a long time to display radiationlevels. Shielding is also crucial Some of the

’24W Schimmerling and S Curtis (eds ), Workshop on the Radi-ation Environment of the Satellite Power System (SPS], Sept 15,1978, DOE, Conf -7809164, December 1979

1251b;d

‘2’Whke, Environment/ Assessment for the Sate//ite powerSystem, Non-Microwave Health and Ecological Effects, op cit

‘*’Program Assessment Report, Statement of Findings, op cit‘2’ Environmental Assessment for the Satellite Power System

Concept Development and Evacuation Program, op clt

risks associated with the reference systemcouId be reduced with additional or innovativeshielding. Analysis is needed to determine ifbetter shielding techniques can be devised thatwould not incur a greater weight or cost pen-alty. Studies are also needed to examine towhat extent additional shielding mass will in-crementally reduce risks of exposure to mostradiation (because secondary radiation can beproduced as the thickness is increased),129 or ifshielding materials can be developed to stopHZE particles.

DOE has concluded that as presently de-signed, the reference system constructionscenario is unacceptable. 130 Risks could bereduced if personnel spent more time in LEO.More study is required to improve the currentassessment and to explore the impacts on thesystem Cost and feasibility of modifications ofthe reference system in order to minimize ion-izing radiation hazards.

I n sum, research priorities include:

●

●

●

●

●

�

measurements of radiation flux in CEO.This can be done with CEO satellites; thespace shuttle and space operations centerwilI provide data on LEO;study of the bioeffects of HZE particles;continued study of radiation bioeffectsand refinement of models;improvement in dosimetry techniques andshielding technology; andfor SPS, improved analysis of exposurerisk, and shielding techniques, considera-tion of exposure limits, and assessment ofthe viability of workers in space: tradeoffsbetween human health, system feasibility,and economics.

12“ProgrJm Assessment Report, Statement of Findings, op cit‘ ‘“l bld

Chapter 9I N S T I T U T I O N A L I S S U E S

Contents

F i n a n c i n g , O w n e r s h i p , a n d C o n t r o l .Space and Energy Sectors . . . .Government-Private Sector RelatPhases of SPS Development.Possible Models . . . . . . . . . .

ons. .

The Implications for the Utility IndustryI n t r o d u c t i o nT h e U t i l i t i e s ’ P l a n n i n g P r o c e s s .

Page

. . . . . . . . . . . . . . . . . 227

. . . . . . . . . . . . . . . . . . . 227

.., . . . . . . . . . 227

. . . . . . . . . . 229

. . . . . . 2 3 0. . . . . . 23.5

. . . 235. . . . . . . 235

Engineering Impl icat ions of the SPS for the Ut i l i t ies Grid . . . 239Regulatory Implications of SPS . . . . . . . . 243General Implications for the SPS . . . . 245

Issues Arising in the Public Arena. . .

. . . ... 247The SPS Debate . . . . . . . . 247Siting . . . . . . . . . . . . . . . . . . . . . . 258

TABLES

Table No. Page

50. Characteristics of the SPS System . . . . . . . . . . . . . . . . . . . . 23651. Major Grid Contingencies . . .23752. Potential for Power Variations From the Reference System SPS . . . .24153. Major Issues Arising in SPS Debate . . . . . . . . . . . . . . . . . . . . . . . 25054. Potential Benefits and Drawbacks of SPS “Technical Options . . . 259

FIG U RE

Figure No, Page

44. Phases of R&D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 238

Chapter 9

INSTITUTIONAL ISSUES

FINANCING, OWNERSHIP, AND CONTROL

The questions of who would finance, own,and control a solar power satelIite (SPS), and towhat extent, are interrelated. As a project thatwould involve the Nation’s space and energysectors, as well as several Government agen-cies, there are numerous issues to be con-sidered regarding the proper allocation of risksand responsibilities. The following discussionwill examine: 1 ) current policy and structure ofthe space and energy sectors; 2) the relationbetween Government and private-sector activ-ities; 3) the importance of distinguishing be-tween the different phases of SPS develop-ment and operation; and 4) possible historicaland hypothetical models for an SPS project.

Space and Energy Sectors

Space

I n the United States, space capabilities havebeen primarily instigated and funded by theFederal Government (with much of the actualdevelopment and construction done by privatefirms under contract to the National Aero-nautics and Space Administration (NASA)).Launchers, launch facilities, and tracking net-works are currently Government monopoliesthat may be leased to private companies,Government agencies, or foreign countries forspecified purposes. Only certain payloads arebuilt and owned by nongovernmental bodies.Within the Government, NASA is responsiblefor R&D of civilian space-systems that, whendevelopment is completed and the operationalstage begins, are turned over to another part ofGovernment or to the private sector. Scientificmissions, such as deep-space probes, are runby NASA, as are launch facilities such as CapeCanaveral. Military and intelligence opera-tions are largely separate even in the R&Dphases, with control exercised by the Depart-ment of Defense (DOD) or specific intelligenceagencies.

Energy

EIectricity is provided by public and privateutilities, which are regional monopolies reg-ulated by State authorities. R&D and construc-tion of generating equipment—turbines, nu-clear reactors, switching gear— is done by pri-vate firms, who sell to utilities. The utilitiesoperate and maintain equipment, build trans-mission lines, and market electricity to end-users Due to severe capital constraints and alack of expertise in space operations, utilitiesare unlikely to own and operate SPS in the waythey currently do with other types of power-plants, though they may well be responsiblefor the ground-receivers. In the case of SPS,there is a question as to who would carry outthese various activities,

Although energy production in the UnitedStates has traditionally been handled in adecentralized manner by private industry, in-creased sensitivity to the importance of energyissues since the 1973 oil embargo has led tovarious attempts at formulating a nationalenergy policy, centered in the newly createdDepartment of Energy (DOE). DOE’s scope andresponsibilities in areas such as basic researchand engineering have yet to be determined;funding is being provided for projects inphotovoltaics, conservation, nuclear power,synfuels, and other areas. DOE can be ex-pected to have a prime role in any SPS project.

Government-Private Sector Relations

What would be the degree of Federal in-volvement with the SPS at different stages,such as R&D, construction, and operation; andin different areas, especially financing, trans-portation and transmission, and marketing?

The arguments for Federal involvement cen-ter around fears that the private sector will notbe able to undertake an SPS project, because

227


of the very high costs and risks, and the longand uncertain payback period. There is alsoconcern that private-sector development, evenif economically feasible, might be detrimentalbecause of monopoly by a single firm or con-sortium, and environmental and internationalpolicy considerations requiring public control.

Cost estimates for different SPS scenariosare very imprecise; the most comprehensiveestimates have been done by NASA for thereference design and calI for a total invest-ment of $102 billion (1977 dollars) over 22years for construction of the first 5-GW SPS,i.e., before any return on investment (see ch. 5).The key questions are whether the private sec-tor can or would ra ise these amounts ofcapital, a n d h o w i n v e s t m e n t c o s t s andmanagement responsibilities might be sharedbetween Government and industry.

Though the reference figures are highly ten-tative, the general magnitude of the projectand its division into discrete stages are likelyto be similar regardless of what design is used.None of the alternatives has been examined innearly the detail of the reference design, large-ly because the technologies are less well-devel-oped. The following discussion will focus onreference figures but should be applicable toany SPS system of similar magnitude.

Difficulties With Private Involvement

A total investment of $40 billion to $100billion over 22 years–with additional muchlarger investments to build a complete sys-tem —would be unprecedented for private-sec-tor financing of a single project.

Private capital can be raised by borrowing,issuing bonds or stocks for sale to the public,or from profits. Especially in the first years,borrowed funds would be available, if at all,only at prohibitively high interest rates. Stocksand bonds would be unlikely to attract largeinvestors when profitabiIity Iies some 30 yearsin the future. Both institutional investors andlarge corporations allocate only a small pro-portion of their funds for high-risk long-termprojects; in some cases, such as pension funds,there are legal limitations on high-risk invest-

ments. Uncertainty, whether technical, politi-cal, or economic wilI deter potential investors.

The incentives required to spur any privateinterest would in themselves involve draw-backs. A company taking a major risk on SPSwould expect to be compensated by exclusivepatents and other guarantees, in effect with amonopoly. Government regulation would haveto take risks into account by allowing a veryhigh rate of return, i.e., allowing the owners tocharge high rates for SPS electricity. A privatemonopoly charging above-average pricescould prove to be politically embarrassing.

An SPS system will require a great deal ofpolitical support both locally, nationally, andinternationally: land-use conflicts, monopolyconsiderations, environmental standards, taxincentives, and radio frequency allocations area few of the political issues that SPS will needto confront. Private development and owner-ship may be seen as leading to an excessiveconcentration of power outside effective pub-lic control

Difficulties With Federal Involvement

Any large long-term project, public or pri-vate, dealing with advanced technology maysuffer from financial and management prob-lems: lack of coordination between parts ofthe program; inadequate supervision of con-tractors; financial and production bottlenecksin specific areas that delay other parts of theprogram; inaccurate initial estimates of costsand completion times, and so on. However,Government programs often have special con-straints that need to be taken into account.Without a profit motive and the discipline ofresponsibility to owners and stockholders,there is less incentive to reduce costs. Civilservice regulations can interfere with hiringand firing and limit salary ranges, decreasingflexibility and making it difficult to retain per-sonnel Annual Government funding producesuncertainties and leaves programs vulnerableto political pressures and pork-barrel com-promises. Government-funded R&D in the pub-lic domain requires special supervision, sincewithout the incentive of exclusive rights topatents and processes, firms doing research

Ch. 9—institutional Issues ● 229

may tend to inflate costs and draw out deliveryscheduIes. 1 Any extensive Government fundingcould divert funds from other space, energy,and R&D programs, whose backers might askfor compensation.

Explicit Federal involvement may increasethe probability of military participation insome or all SPS activities, complicating mostfo rms o f in te rna t iona l coopera t ion andpossibly leading to detrimental changes in theSPS design or operating characteristics.

Finally, a federally financed or owned SPSwould increase centralized control over an im-portant sector of the economy and would leadto greater politicization of America’s energyindustry.

Phases of SPS Development

Federal v . pr ivate investment is not aneither/or proposition. I n general, Federal in-volvement would be necessary in the earlystages, and become increasingly less so,assuming the system remains technically andfinancially feasible, as the project becomesoperational. The basic problem is how to dif-ferentiate between the various and overlap-ping stages and ensure adequate managementand continuity throughout.

SPS development can be divided into suc-cessive stages (as described in ch. 5): research,engineering, demonstration, and so on. Federalfinancing and management of the researchand engineering phases might turn into a com-bined Federal-private program as more directlycommercial phases were undertaken. Thequestion is at what point and to what degreeprivate investors will be willing to enter theproject. On the one hand, investors wouldprefer to see as much as possible paid for bythe Government; but early investors wouldhave an advantage in setting program pri-orities and establishing a dominant position.Involvement of owners and operators at theearliest possible stages would help to ensurethat the completed system is suited for com-

I Mark Cersovltz, “Report on Certain E conornlc Aspects of theSPS Energy Program, ” OTA ( ontrdf I No ()} 3-26700, 1980, pp1719

mercial operation, that internal proceduresand structure are appropriate to private owner-ship, and that the transition from developmentto operation proceeds smoothly.

The SPS would consist of a number of dis-tinct systems, each of which must be devel-oped separately and simultaneously: e.g.,transportation, energy conversion and trans-mission, orbital construction, and ground sta-tions launchers and solar cells, for instance,may be useful and profitable regardless ofwhether SPS is built or not. Should theirdevelopment be charged to SPS? If so, theiruse and sale might help to offset the risks ofthe program as a whole; on the other hand,their development adds considerably to theSPS cost. It can be argued that public fundingshould be reserved for those parts of the proj-ect that private investors will not handle andthat segments with near-term commercial ap-plications should be left to the private sector.As in any complex program, there is the ques-tion of internal apportionment of risks andbenefits. Successful items can help to sub-sidize less profitable projects, provided fundsare transferable from one division to another,allowing for risky high-return investments, butalso for Edsels.

In the case of SPS it is essential that eachcomponent be developed on time and to theproper specifications for the system as a wholeto function. Management must be given suffi-cient authority to produce appropriate prod-ucts., even if particuIar divisions suffer; say, ifSPS solar cell designs are not optimal forground-based users. Major investors in a pri-vately funded SPS wiII have their own particu-lar interest–aerospace companies in launch-ers, electronics firms in microwave hardware,utilities in delivered power — that could com-promise the project’s overall goals. Govern-ment supervision, whether by partial owner-ship, reguIatory oversight, or appointment ofd i rectors, may mitigate certain confIicts but isno guarantee of smooth saiIing. Federal con-cern for a broadly conceived public interestmay be affected by a desire for continued con-trol and supervision, or by the interests of par-ticuIar agencies. For instance, DOD may place


emphasis on booster and LEO to CEO trans-port development for i ts use (see ch. 7) ,perhaps affecting launcher design or the allo-cation of program funds. NASA may wish toemphasize and prolong the R&D phase. An-nual budget review may increase costs by cre-ating uncertainty and requiring project mana-gers to spend large amounts of time drawingup and justifying annual budgets.

Possible Models

Perhaps the best way to further examinepossible financing and management scenariosis through historical and hypothetical modelsthat might be applicable to SPS. In each in-stance there are several questions to be asked:1) Is it complete: can this model support anSPS program from start to finish, or is it ap-plicable only to certain phases or components?2) How are risks apportioned: who pays, andwho reaps the benefits of a successful project?3] How efficient and flexible is it: can it adaptto changing economic and technical circum-stances, and can it attract support from avariety of sources, particularly foreign in-vestors?

Historical Models

NASA

NASA is an independent Governmentagency with a general mandate to engage inR&D and testing and to conduct launches forcivilian space activities. Although NASA has inthe past centered its efforts on high-visibilitymanned projects, such as Apol lo and theSpace Shuttle, it has also conducted majorprograms in te lecommunicat ions, remote-sensing, and the sciences, such as the Vikingand Voyager interplanetary probes.

NASA is funded by general tax revenues ap-propriated annually by Congress. NASA fundsare overwhelmingly—90 to 95 percent— spenton outside contracts with private firms, re-search centers, and other Government agen-cies, foreign as well as domestic. NASA itselfhelps to set priorities and policies, overseesand coordinates contractor performance, and

operates specific faciIities (on a cost-reim-bursable basis) for research and launches.

●

●

Advantages. – NASA is already in place, with22 years of experience. It has well-estab-lished relationships with private contractors,other parts of the Government, and foreign. companies and Government agencies. It hasthe technical and administrative expertise toevaluate most of the major components ofthe SPS, many of which— interorbit transfervehicles, assembly and construction facil-ities — are part of current NASA plans.

Disadvantages. –Annual funding for NASAprojects creates difficulties in implementinglong-term plans that are likely to go in andout of pol i t ical favor. I t a lso hampersagreements with foreign firms and agencies,that have had problems in the past whenNASA budget cuts have forced cancellationof joint programs. Legislative changes topermit ongoing funding would greatly im-prove NASA’s position.

NASA’s emphasis on R&D and prototypedevelopment (NASA’s ability to participatein commercial ventures is unclear and sub-ject to restrictions) could create problems indeveloping a commercial product such asSPS; NASA might have to relinquish controlafter the demonstration phase. There isoften reluctance to complete R&D phases,since completion means loss of the project.Coordination with eventual users and own-ers may be underemphasized. AmendingNASA’s charter to allow for beginning-to-end development and operation would alle-viate this problem, but might be harmful tothe agency’s R&D mission.

The broad scope of NASA activities hasmeant that, within and without the agency,there have been conflicts over the relativeprior i ty of scient i f ic v. appl icat ions, ormanned v. unmanned missions. The SPScould be criticized for diverting funds andattention from competing programs; intra-agency squabbling might interfere with theproject. Excessive concentration on SPScould prevent NASA from accomplishingother tasks, although many aspects of SPS

Ch. 9—Institutional Issues . 231

development would be applicable to otherspace activities.

Funding all, or even a large part, of theSPS through general tax revenues would pro-duce strong pressure for continued Govern-ment control. Since the risks are borne, in-voluntarily, by the general public, justifica-tion in the form of visible public benefitsmay have to be provided. These benefitscouId take the form of electricity-rate reduc-t ions, tax-reduct ions, or other types ofreturns. Turning SPS or SPS technology overto private profitmaking firms may be unac-ceptable. Such a prospect could discourageprivate interest; this difficulty is common toall publicly financed ventures.

TENNESSEE VALLEY AUTHORITY (TVA)

TVA, the Nation’s largest utility, was estab-lished in 1933 to provide power for a regionthat commercial utilities were not willing todevelop. Unt i l 1959, TVA received annualFederal appropriations; since then it has raisedcapital by issuing bonds, the amount of whichis subject to congressional approval, as well asby charging customers for its services. At thattime, TVA was forbidden from expanding itsservice area, in order to avoid competitionwith private utilities. In 1978 TVA’s borrowingauthority was raised to $30 billion. 2 A TVA-type independent authority, initially financedby tax revenues and authorized at some pointto issue self-backed bonds, could be a possiblemodel for SPS development and operation.

Ž Advantages. — Initial F e d e r a l f i n a n c i n gwould allow for pursuit of R&D and proto-type development. Adoption of TVA prac-tices, such as the absence of civil service re-quirements, would free the authority fromcertain Government inefficiencies. Issuingbonds would subject the issuer to the finan-cial judgments of investors and make therisks of the project more palatable, sincemuch of the investment would be voluntaryrather than by congressional or executivedecision. The concentrat ion of a newlyestablished authority on a single-projectwouId avoid the internal conflicts inherent

“’increasing the TVA Bond Celling, ” hearings before SenateEnvironment and Publlc Works Committee, Feb 23, 1979

in having it undertaken by an establishedagency.

● Disadvantages. — It is not clear at what pointprivate financing would become availableon a large scale, and hence how much mustbe spent out of general taxes. The larger thepublic part of the investment, the morelikely are the publ ic- interest problemsoutlined previously.

Financing through bonds does not providefor the type of accountabi l i ty avai lablethrough congressional appropriation, orthrough public ownership via the stock mar-ket Specific arrangements for public over-sight, given the monopoly position of suchan entity, would have to be made. Owner-ship of patents and products generated bypublic investment would have to be clari-fied, given the possibility of competition be-tween private firms and the authority in thelatter stages of development and operation.

HIGHWAY TRUST FUND

Since 1956 the Federal Government hasspent over $7.5 bill ion (in current dollars) tofinance the Interstate Highway System and anumber of other road and highway programs.The money for these investments has beenchanneled through the Highway Trust Fund,which receives revenue from taxes on gasolineand diesel fuels, on heavy trucks, and othersources. These funds are not spent by theFederal Government, but apportioned to theStates to pay for their share of highwaysystems.

The rationale for Federal financing was thatan improved road-system would aid the Na-tion’s defenses, as well as improve commerceby decreasing transportation costs. The systemwas planned on a national scale, but takes ad-vantage of existing State highway departmentsto implement the proposed network. No cen-tral construction or maintenance firm wasneeded 3

The distinctive feature of the system is itsuse of specific taxes on a commodity directlyrelated to the project. Through the tax on gaso-

‘Porter (’ wheeler, Hjghwa y A \\[jtance Programs A Ffl\torlca/~~erfpf,( ~lve, Congre$slonal Buclget Of flee, FebrUaw 1978


line and diesel fuel, transport users have con-tributed in proportion to their total trans-portation expenditure. An additional tax onheavy commercial trucks has ensured thatlarge users, who were responsible for a highproportion of maintenance costs, would con-tribute appropriately. Unlike tolls or directfees for highway usage, revenue could be col-lected before the roads themselves were com-pleted. An analogous tax to finance a fund forSPS might be levied on current domestic andcommercial electricity consumption (thoughfrom a strictly financial point of view the taxneed not be directly related to energy con-gumption. )

●

●

Advantages. —The use of a designated taxprovides more assured and predictable fund-ing than general revenue taxes that need tobe reallocated on a yearly basis. By taxingelectricity consumption the costs would beborne by the future beneficiaries of SPS. Ifdesired, taxes on other forms of energycould also be imposed; all energy taxeswould have the added benefit of encourag-ing conservation. As private investment wasfound, the tax could be reduced, or revenuescouId be spent elsewhere.

The size of the tax, if levied on electricityalone, would not have to be large to gener-ate significant revenue. A tax of 2 mills/kWhwould produce over $4 billion per year (atcurrent consumption rates) while raisingconsumer costs by less than 5 percent.4

Disadvantages. — A tax on electricity maycause consumers to switch to other forms ofenergy, harmin g utilities Higher electricitycosts wil l inf late prices of electr ici ty-intensive products, such as alum inure.

The organizational framework to managethe SPS will have the same difficulties asother Government agencies, especialIy inhandling the transition to private ownership.

U.S. SYNTHETIC FUELS CORP.

The Synfuels Corp. was established in June1980 with a specific mandate to produce theequivalent of 2 million barrels per day of crude

‘ P e t e r Vajk, SPS FInancIa/, Mandgernent 5( en,]rlo~, DO F con-

tract No EC77-C-01 -4024, October 1978, p ;6

oil by 1992. The corporation is instructed to doso by, in decreasing order of preference: 1)price guarantees, purchase agreements, orloan guarantees; 2) loans; 3) joint ventures. Thecorporation’s goal is to faciIitate private-sectorsynfuel production, and to produce synfuels it-selt only as a last resort. Initial funding was setat $20 billion, with total funding of up to $88billion envisioned. Funds are to be providedfrom the windfall-profits tax on domesticallyproduced oil. 5

A possible SPS corporation would resemblethe Synfuels Corp. in being a high-cost energyproduction plan with a specific goal and time-table It would differ in that it would involvecreating a single firm rather than funding nu-merous private enterprises.

●

●

Advantages. — The Synfuels Corp. has the ad-vantage of a discrete goal and timetable,with maximum flexibility as to achievement.The etmphasis on price and loan guaranteesto encourage rather than replace conven-tional financing arrangements should re-duce the cost, assureing projects are suc-cessful. Direct Government control will beavolded, unless no private ventures what-ever are forthcoming.

Disadvantages. – It is far too early to tellwhether the Synfuels Corp. will accomplishIts goal, or wiII do so without exorbitantcosts Critics fear that an indiscriminatory‘shotgun“ approach may result in fundingnumerous uncompetitive ventures, in thehope of finding one that works; while therevenue taken from the oil companies intaxes may prevent the development of addi-tional fuel sources. The promise of “easy”Government money and soft loans may dis-courage efficient financial and managerialpractices.

While the Synfuels Corp. can pick andchoose from a number of relatively well-developed and predictable projects, the SPSCorp would have to generate i ts ownorganization. The SPS Corp. couId not, espe-cially at first, simply be a channel for fund-ing to private firms, or for loan guarantees.

— -- —----~ n(’r~~ $~)( (/r/[y A et, Publ IC Law %9,24, 96th Cong , j une )(),

1 9 H ( ) ill [{


COMSAT

Comsat was founded in 1962 as a federallychartered corporation to establish and runsatellite communications (see ch. 7). Comsatdid not receive direct Federal funding, but wasgiven the fruits of extensive and continuingNASA research on telecommunications satel-lites,6 as well as the right to use NASA launchservices on a reimbursable basis (which doesnot reflect R&D costs). The Government re-tained a measure of control through Comsat’soperating charter and by appointing boardmembers, who were initialIy divided betweenGovernment, communications common carri-ers, and private investors. Capital was raisedby issuing stock, which from the outset waswell-received by investors. As of 1979, Comsatstock was held overwhelmingly by noncom-mon carriers; 3 of 15 Board members werePresidential appointees, the rest being electedby stockholders.

● Advantages. — A Comsat-styled SPS corpora-tion would be independent of direct Govern-ment control and free to operate as a pri-vate, profitmaking corporation. Governmentsupervision would be provided without theneed for onerous restrictions. Comsat hasbeen highly successful internationally via itsparticipation in lntelsat, and a “Solarsat”corporation might find it easier to engage ininternational activities than would a Gov-ernment agency. Such an organization couldinherit the results of Government-financedR&D and engineering with less of a politicaloutcry than if control were to be turned overto established private firms such as aero-space or oil companies; Comsat was estab-lished in large part to prevent AT&T fromgaining a satelIite communications monopo-ly.

● Disadvantages. — Issuing common stockwould not suffice to raise capital for theearly development stages. The transitionfrom Government to private funding would

‘ N A S A c o m m u n i c a t i o n s r e s e a r c h was phased out under the

N i x o n admlnlstratlon, which l o o k e d to Comsat a n d t h e p r i v a t e

sector to maintain U S preem Inence In commun Icatlon satel I tte

t e c h n o l o g y However, In 1978 the Car te r admlnl~tratlonreinstated NASA’s leading role In communlcatlon> R&D, largelyto offset foreign government R&D effortj

83-316 0 - 81 - 16

have many of the difficulties already men-tioned.

PRIVATE JOINT-VENTURES

A private SPS project could be undertakeneither by an established firm, a new company,or a joint-venture of existing companies andfinancial institutions. For the reasons men-tioned (high cost, uncertainty, long periodbefore payback, and too many eggs in one bas-ket) no single firm, whether new or established,iS I ikely to undertake SPS development un-aided

A joint-venture or consortium is formedwhen a single project or enterprise is of in-terest to several parties, no one of which iswilIing to finance or manage it on its own, aswith the Alaskan pipeline. Or, companies maybe legally prevented from exercising sole own-ership for antitrust reasons, while a singlesystem may be technically desirable. For in-stance, the Federal Communications Commis-sion (FCC) required Comsat and IBM to add athird partner (Aetna Insurance) when formingSatellite Business Systems (SBS). In any con-sortium, partners are Iikely to have a particuIarinterest in the consortium’s success above andbeyond immediate profitability. In SBS’s case,IBM Corp. and Aetna intend to be majorcustomers of the system, and IBM Corp. willsuppIy operating equipment. 7

● Advantages. — Potential major partners in anSPS consortium would be: aerospace com-panies, oil/energy firms (including possibleemergent industries in photovoltaics, syn-fuels, or other energy sources); and electricutiIities. A consortium that could draw onthe resources of firms in these major indus-tries would find it easier to borrow money,selI stocks and bonds, and use profits forSPS investment. According to most esti-mates, the utility industry alone will bespending hundreds of bilIions of dolIars overthe next 30 years to replace old generatorsand build new capacity; an SPS projectwouId not constitute an unmanageable pro-portion of total industry investment,

—.—( ourt Upholds SPS, ” Avlatlon Week and Space Technology,

Vldr 1 ( I 1980, p 22


● Disadvantages. – However, there would stillbe difficulties in funding the initial phases.While aerospace and electronics f irmswouId begin to benefit relatively early in theproject, oil/energy companies and utilities(that have the bulk of the resources) will seereturns only towards the end. utilities in par-ticular, as part of a publically regulated in-dustry, will find it difficult to set rates so asto raise funds for R&D or speculative pur-poses, as opposed to purchase of more es-tablished technologies. For instance, the $2billion Great Plains coal gasification projectwas to be financed by a surcharge on gasrates charged by consortium members. Al-though DOE approved the rate hikes, cus-tomers — s u c h a s G e n e r a l M o t o r s — a n dState officials protested against being askedto subsidize synfuels investments.8 The Fed-eral district court then disallowed DOE’s ac-tion, effectively blocking the project.

Consortia are more likely to arise in the in-vestment and operation phases, when indi-vidual members’ interests are more clearlydefined, and risks have been reduced. Thevery high costs and large size of a full-scaleSPS system, as well as the monopoly dangersof a system under the control of single com-pany, may make inter- or intra-industry con-sortia attractive.

Hypothetical Models

In discussing possible SPS financing sce-narios, some writers have proposed completelynovel methods with no historical precedent.Foremost among them are the Taxpayer StockCorp., a new form of Government financing;and a private approach, the staging company.9

TAXPAYER STOCK CORP.

Under this method, taxpayers would receiveshares in a public corporation, financed bygeneral tax revenues, in proportion to the per-cent of taxes used to finance SPS. Shareholderscould then trade their shares on the market, aswith any other corporation. Those who did not

‘Robert D Hershey, “Gasification Plant Rising Amid ManySnags, ” New York Times, Nov 17, 1980, p 1

‘For further discussion see Vajk, op clt , pp 32-40

wish to support SPS could sell their stock forimmediate returns.

Although such a scenario has the advantageof diffusing SPS ownership, it is difficult to seehow SPS shares would retain their full value onthe market; if they did, funding via taxes wouldnot have been necessary in the first place.Shareholders would instead be left with deval-ued pieces of paper, unless they are purchasedby the Government —with tax dollars — tomaintain a reasonable pr ice. This wouldamount to a straightforward Government sub-sidy.

STAGING COMPANY

The staging company is essentially a boot-strap operation whereby sufficient revenuesare generated during the R&D phase to attractfurther capital. The firm would invest its initialfunds in existing aerospace and high technol-ogy companies, gaining patent rights and newtechnology—via joint ventures—as well asconventional investment returns. The successof the company’s first investments, and its in-creasing expertise, wou ld a t t rac t fu r therspeculative investors; the staging company isin effect a mutual fund. Eventually, the com-pany would begin to finance SPS R&D directly,concentrating on those aspects with near-termreturns. At some point conventional financingwould become available for the investmentand operation phases.

Such an approach is unlikely, unless its firstinvestments turn out to be in budding Xeroxesor IBMs, to raise the $33 billion estimated tobe necessary for the reference design R&D andprototype phases. In 1978 Christian Baslerestablished International Satellite Industries,Inc., to test his concept; it failed when neitherNew York nor California would allow ISI stockto be sold. 10

Conclusions

It is clear from the review of possible modelsthat there are many ways to finance the latterstages of a successful SPS program, but that

‘(’(’ onversatlon with Stephen Cheston, President, Institute forthe \oclal \clence Study of Space, December 1980

Ch. 9—lnstitutiona/issues . 235

the initial phases would in all likelihood haveto depend on some sort of Federal funding.Some combination of the suggested methodsmay prove attractive.

In establishing an SPS organization, atten-tion should be paid to several factors. First,there should be provisions for stopping theproject if it becomes unfeasible. Large initialinvestments wiII create considerable momen-tum, which may cause wasteful developmentto continue unless authority is given to ter-minate. This is especially true for Governmententerprises.

“Gersovitz, p 36

Second, at all phases careful attention mustbe given to public policy concerns: environ-mental protection, regional interests, and mili-tary involvement. Private companies must notthink SPS can be developed in secrecy or with-out reference to a wide public environment(see ch 8, Issues Arising in the Public Arena).

Third, early and continuous efforts shouldbe made to involve and inform potential inter-national partners to attract investment aid,forestall competition, and ensure that theglobal market for SPS is kept in mind whentechnical and managerial decisions are made.A narrow focus on domestic concerns, by Gov-ernment or industry, may jeopardize SPS un-necessarily. (see ch. 7, International Implica-tions).

THE IMPLICATIONS FOR THE UTILITY INDUSTRY

Introduction

The interest of the utilities in the SPS woulddepend on technology related factors such asstability and reliability, as well as those moredirectly related to the economics of electricitygeneration and distribution (i. e., siting, capitalinvestment and Government regulation). Eachof these factors would require more study asmore is learned about the various SPS alterna-tives. From what is now known, it appears thatthe technical barriers to integrating SPS intothe utility grid are solveable, particularly if theunits of SPS generated power are of the orderof 1,000 MW or less. It is also apparent that forthe utilities to develop sufficient confidence inSPS, one or more units would have to be testedover time.

More troublesome are the economic risks ofSPS. When considering adding a new pIant,utilities must plan far ahead of actual systemintegration for the associated transmissionlines and other generating capacity (i.e., in-termediate or peaking plants to supplementthe baseload powerplants). Failure of the SPSto meet expected implementation deadlineswould result in severe economic loss for theutiIity. The need for extensive trials and testing

of a new plant render it highly unlikely that theSPS could become part of utility grids untilseveral years after a commercial prototypewere built. Although SPS could force some reg-ulatory changes, there seem to be no strongregulatory barriers to implementing SPS.

Table 50 summarizes the projected charac-teristics of the SPS that would be of interest tothe electrical utilities.

The Utilities’ Planning Process

The Current Situation

Because of the recent rapid rise of all energycosts and subsequent efforts to conserve, theutilities find themselves in an uncertain posi-tion for the future. In the past, the utilities ex-perienced fairly steady, high peakload growthrates, resulting in a correspondingly high rateof growth (7 percent) of generating capacity, arate that leads to a doubling of capacity every10 years. Recently, however, average peakloadgrowth has fallen sharply. Lower economicgrowth rates and price-induced conservationefforts have had a strong effect on consump-tion I n response, the average growth of in-stalled generating capacity has also fallen. The


Table 50.—Characteristics of the SPS Systems

The reference

System character is t ics s y s t e m ”

Delivered power from each

s a t e l l i t e ( a t t h e b u s b a r )

T o t a l s y s t e m o f . . . . . . . .

I m p l e m e n t a t i o n r a t e . . . . . .

Start of deployment. . . . . . .

L i f e t i m e o f e a c h s a t e l l i t e

T r a n s m i s s i o n f r e q u e n c y . . . ,

D e s i g n e d c a p a c i t y f a c t o r . ,

R e c t e n n a s i z e . . . . . . . . . .

T e r r e s t r i a l c o n v e r s i o n m o d e .

Major potential causes of

i n t e r r u p t i o n .

5,000 MW300 GW2 per year for

30 yearsA.D. 2000

30 years2.45 gigahertz(i.e , microwave)

90 percent10 km x 13 km at

35° Iat. plus 1 km

buffer

Microwave dipole

Sol id-s ta te sandwichd e s i g n ”

1,500 MW

Not pro jected—

2010-2020(estimate)

30 years2.45 gigahertz

90 percent6.5 x 5.5kw at 35° Iat.

plus 1 km buffer

Microwave d ipole

Laser system”

500 MWNot projected

—

2010-2020(estimate)

30 years10 microns (infrared)

70-80 percent

36 meter diameter

Thermal convers ion

Mirror system(baseline SOLARES)15

135 GW (10 GWpossible)

810 GW over 67

2010-2020 (estimate)

?Reflected sunlight —

I.e., continuous

s p e c t r u m?

39-km diameter

Thermal , photovo l ta ic

antenna-rect i f ie r and antenna-rect i f ie r and c o n v e r s i o n

inver ters inver ters

Maintenance, Maintenance, ec i lpses During any thick cloudOf SatelIite? (max 2 ½ h r

During any thick cloud

satelIite eclipses cover , maintenance m a i n t e n a n c e

(max. 21/2 hrnear equinoxes)

near equinoxes)

1“’Sa tellite Power System Concept Development and Evalua-tion Program Reference System Report DOE report NoDOE/E R-0023, October, 1978

13G. M. Hanley, et al , “Satellite Power Systems (SPS) ConceptDefinition Study, ” First Performance Review, Rockwell Interna-tional Report No SSD79-0163, NASA MSFC contract NoNAS8-32475, Oct. 10, 1979

14W. S. Jones, L L Morgan, J. B. Forsyth, and J P Skratt,“Laser Power Conversion System Analysis: Final Report, Vol. I l,”SOURCE Off Ice of Technology Assessment

U.S. total of installed electrical generatingcapacity in 1978 and 1979 rose by an averagerate of 3.1 and 3.2 percent respectively, ratesthat cause a doublin g of capacity every 22years. Growth rates in some sections of thecountry have been zero or negative in thesame time span.

As the high growth rate of electricity de-mand and subsequent expansion of the utilityindustry has subsided, the industry has had torethink its posture with respect to adding newcapacity, I n addition to the uncertainties offuture demand, increasing costs for fuel, morestringent environmental standards, public op-position to nuclear powerplants and techno-logical changes are also affecting the planningprocess. What is perhaps of most concern,however, is the increasing difficulty privateutilities face in raising the large amounts ofcapital needed for building new capacity orreplacing old, inefficient plants

In response, the utilities are placing moreemphasis on understanding the interaction be-

(Lockheed Missiles and Space Co , report No LMSC-D67 Mbb,NA5A report No CR-1 7952 ], contract No NASA ;-211 37, Mar 1 ~,

1979

K W II II I man, W P G I I breath, and S W Bowen, ‘OrbitingMirror\ t<)r Terre$trlal E nergv Supply, ” In ‘ Radlatlon F nergv Con-ver~lon in ~pacej Progre\s In A $tronaut~cj & Aeronauflc\ Serle\,K W EIII lman (ed ), VOI bl (New York Al AA, July 1978), pp(>1 ~lo

tween reserve margins, types of capacity, andreliability requirements. They are also sharplyreducing the amount of new capacity, delayingInstallation of some plants, canceling others,Although on average the difference betweentotal capacity and average annual load isgreater than ever before, some industry ex-ecutives have expressed concern that thesepl,lnned reductions in generating capacity wi IIIe,ive the United States seriously deficient ifthe current trend towards lower growth ofpeak demand reverses itself. others, generallyoutside the industry, have suggested that in-creased conservation measures can bring theneed tor new generating capacity to zero orlets, Ieavlng the industry, on the average, inthe posit ion of simply replacing or refurbishingoutmoded plants

Planning Process

U S generating capacity in 1980 was about600 glgclwatts. * The peak load that this capaci-— ——. .—

1 ~ IX< I ,1, i t t (c; w ] or IJOWpr I \ e(\u,1 I ( 01 ,()()() rmegc)w,itt \

Ch. 9—institutional Issues ● 2 3 7

ty is expected to serve is about 410 GW. Tomeet this load, the generating capability iscomposed of about 10 to 15 percent of peak-ing units, 20 to 25 percent of intermediate and60 to 65 percent of baseload generating units.A planning reserve margin of 20 to 25 percentabove peak demand is required to allow theutility to continue to serve the customer whenany of the operating units fails and when un-usual load peaks occur.

For a given utility system, the reserve isrelated directly to the expected reliability ofthe total system. Although the exact amount ofreserve needed is currently debated within theindustry, I b the rule of thumb that most utilitysystems use to calculate their necessary re-serve is that they must have no more than onegenerating outage or failure to meet expecteddemand in 10 years, a failure that may be asshort as a minute or as long as several hours. I npractice, this criterion results in some days ofline voltage reductions and a few days of ap-peals to customers for conservation, but a verylow probability of outage in any one year.

A utility is not simply a set of generatingplants, transmission lines, and transformers. Itis a complicated interactive network in whichindividual components af fect each otherthrough an intricate set of feedback loops. Afailure in one part of the system may set off afailure in another part. Adequate reliability isensured by building enough redundancy intothe system to meet most cont ingencies,whether from system failure or from unex-pected surges in demand.

The amount of redundancy required for agiven system depends heavily on the reliabilityof the equipment in the system and the util-ities’ experience with them. To calculate thenecessary reserve, the utilities generally useseveral methods, the simplest of which, calledthe contingency outage reserve criteria, willserve to illustrate the most important featuresof reserve planning.

“A Kaufman, L T Crane, J r , B M Daly, R J Profozich, andS j Bodily, “Are the Electrlc Utllltles Gold Plated?” committeeprint, 96-1 FC 12 Committee on Interstate and Foreign Com-merce, United States House of Representatives, 1979

After projecting the peak load requirementsof the system, utility planners add an amountof generating capacity equal to that whichmight be unavailable because of scheduledmaintenance. System reliability will then beachieved if sufficient excess capacity over andabove this amount is available to cover one ormore of the sorts of contingencies I isted intable 51.17 This method tends to treat thesystem in gross terms and does not generallyallow for important details of a given systemsuch as the variations of peak load throughoutthe year or the percentage of time it will bet apable of generating given levels of power attlifferent seasons. For this, a more sophist i-( ated analysis would be needed.

Planning for New Technologies

The SPS is one among many new technol-ogies that the utilities are considering in plan-ning for the future. These include regiona/technologies such as ocean thermal energyconversion and geothermal; intermediate orpeaking technologies such as wind, solar ther-mal and solar photovoltaic without storage;,~nd baseload possibilities such as advancedcoal, breeder reactors and fusion. I n addition,~ome utilities are considering grid connecteddispersed technologies such as solar thermal,solar photovoltaics, wind, and fuel cells. Plan-ning for such a mixed bag of technologies is acomplicated and time-consuming process. Asfigure 44 illustrates, the time from the initialconception of a new technology to actual in-tegration into the utilities’ grid can be extreme-ly long– up to 40 years or more. Not only mustutility suppliers develop the components ofthe individual technology, they must make ittechnological Iy and economical Iy attractive to

‘ Ibl(j

Table 51 .—Major Grid Contingencies

1. Loss of the largest generating unit in the system2. Loss of the two largest generating units in the system3. A failure in the largest transmission facility in the system4. A combination of the above5. An error of a specific magnitude in load projection

SOURCE A Kaufman, L T Crane, Jr., B. M. Daly, R J. Profozlch, and S. J.Bodily, “Are the Electrlc Utilitles Gold Plated?” colnmlttee print,96-IFC 12. Committee on Interstate and Foreign Commerce, UnitedStates House of Representatives, 1979.


Figure 44.— Phases of R&D

I — I

1000

V) 100Gs

10

10 10 20 30 40

Years

SOURCE: R L Rudman and C. Starr, 1978 “R&D Plannlng for the Electric UtllltyIndustry, ” In Energy Techrro/ogy v G o v e r n m e n t I nstltutes, Inc ,Washington

the utilities and, in addition, develop a largesupportive infrastructure. Thus, the vast bulkof the time spent in the long chain of technol-ogy development is in the phases followingscientific feasibility— newly conceived tech-nologies are not I ikely to fill near-term supplydeficiencies.

Assuming that an engineering demonstrationof a new technology is successfu 1, its ultimatefate would depend on several factors whose in-fluence can only be seen dimly at the timewhen scientific feasibility is proved. Com-parative costs are a prime consideration, butpublic acceptance, the complexities of thetechnology, and the ease with which it can beintegrated into the existing utility infrastruc-ture are also important (see ch. 6). The utilitiesuse some or all of the following criteria tojudge a new technology: 18

ECONOMIC CRITERIA● Cost to the User. — Bus bar costs are impor-

tant but an expensive long-distance trans-mission and distribution system may price atechnology that is otherwise competitive atthe busbar out of the market. This problemcould apply to any very large, highly cen-tral ized faci I ity.

‘“R L Rudman and C Starr, “R&D Plannlng for the ElectrlcUtility Industry,” In f nergy Techrro/ogy V (Washington, D CGovernment In$tltute$, I nc , 1 978)

●

●

Reliability. – Plants that are highly capitalintensive must operate at high capacity fac-tors in order to minimize electricity costs.Thus, numerous forced or unplanned shut-downs for a given plant would make its tech-nology less desirable. In general, a new tech-nology can be expected to sustain a higherrate of forced or unplanned shutdown thana more mature one. Current mature nuclearplants and coal plants with scrubbers sustainforced outage rates as low as 15 and 19 per-cent of their total availability respectively.As the industry gains even more experience,it wil I probably be able to reduce this rateeven more.

Ease of Maintenance. — It is extremely im-portant to be able to maintain and repaircomponents of the generating system quick-Iy and easily. Nuclear and fossil fuel plantscurrently experience planned outage ratesof 15 and 10 percent, but utility expertsbelieve that these rates can be reduced byseveral percent. Here again, mature technol-ogies fare better than newer ones. However,the percentage of maintenance doesn’t tellthe whole story. The timing of the mainte-nance is also important. If it is possible toplan maintenance during periods when elec-tricity peak loads are lower, the adverse ef-fect on the utility is thereby reduced.

RESOURCE AVAILABILITY

Here, fossi l or other depletable energysources wil I suffer in competition with re-newable sources such as wind-, solar-, fusion-,or breeder-generated fissile material. Further,because the Sun or wind are more available insome regions of the country than in others, ter-restrial renewable technologies wil I vary intheir attractiveness.

SYSTEM CAPABILITY AND FLEXIBILITY

● Control and Operating Characteristics. — Themore stable a power system, the better.Short-term transient outages must occurunder conditions that allow the utility gridt o a c c o m m o d a t e t h e m a s a m a t t e r o fcourse.

———“1 bld

Ch. 9—institutional Issues “ 239

●

●

●

Ability to Tolerate Abnormal Events. –A sys-tem that is otherwise acceptable to theutilities may fail to be adopted because it iseasily disturbed, i.e., small perturbations inoperating mode lead to wide swings of elec-trical output.

Unit Rating. –Although economies of scaleare very real in generat ing equipment,smal Ier capacity units may often be desir-able, because they are easier to repair andreplace than the large ones.

Environment/ Issues. — Environmental im-pacts produce an economic cost that, whileoften impossible to specify, have a strong ef-fect on the acceptability of a given tech-nology. I n addition, some technologies mayhave environmental side effects that areunacceptable no matter what price the uti I i-ty is willing to pay (e. g., the potential effectsof the addition of large amounts of carbondioxide to the atmosphere).

LICENSING

“Licensing . . . is currently the largest singleissue facing al I new technologies. ”2° The issuesthat will affect the licensing procedure such assiting, health and safety, and environmentalconcerns must be identified and reckoned withearly in the development of the technology.They also have a direct effect on the cost of atechnology.

Once a generating technology has proven itscommercial feasibi l i ty , i t general ly takesanother 20 years or so for i t to be usedsignif icant ly . The complexi ty of the tech-nology, institutional barriers, market growth(housing, industry, etc. ) market initiative(dispersed v. central use), and system size willall have their effects on the rate at which agiven technology will penetrate the total utili-ty market.

Engineering Implications of the SPSfor the Utilities Grid

The SPS would make numerous specia ldemands on the utility grids. Some are relatedto the fact that the primary generator or col-

‘“l bid

Iector would be based in space. Others arecharacter ist ic of a l l large-scale baseloadtechnologies. In this section, we will proceedthrough each technology, citing the most im-portant effects each alternative will have onthe utilities.

The Reference System

● 5,000-M W Capacity. – Because of the gridreliability requirements, the large size of thereference system plant would limit the num-ber of individual utilities or utilities’ systemsthat could accommodate it. As a rule ofthumb, a utility generally will not purchase asingle unit that ~wou Id constitute more than1 0 to 15 percen t o f the u t i l i t y ’ s to ta lgenerating capacity. ” In other words, asingle plant must be no more than one-halfof the system’s total reserve capacity of 20to 25 percent.

If a utility could accommodate a first SPSof 5,000 MW, it could accept another pro-vided it met a less stringent application ofthe penetration rule. In other words, the sys-tem would benefit somewhat by redundancyof generating units provided there was a lowprobability of both failing at once.

As an example, for a utility to accept a50,000-MW satellite, it must have a systemcapacity of 5,000/0.13 = 38,000 MW. Thisexceeds the capacity of any single currentutility. Assuming current average rates ofgrowth of 3.2 percent for the industry, itwould exceed the capacity of all utilitiessave TVA in the year 2000. It might, ofcourse, be possible for a group of severalutilities with the appropriate total capacityand adequate grid interconnections to takeon 5,000 MW of power. According to therule for reserve capacity, for the group tothen assume another 5,000 MW, its totalcapacity would have to be large enough forthe two satellites together to constitute 20percent or less of a system capacity of50,000 MW. The exact percentage any givenconsortium of utilities would be willing to

——‘ ~ J Donalek a n d ) L Wtlysong, “lJtillty I n t e r f a c e R e -

quirements for a Soiar Power System, ” Harza Erlglrleerlrlg CO ,DOE contract No 31-109-38-4142, report No DO E/E R-0032, Sep-tember 1978


●

●

accept would depend on its view of theprobability of two SPS units and anotherunit or transmission line failing at the sametime (see table 52).

As an additional consideration, it shouldalso be noted that supplying 5 GW of re-serve power from elsewhere in the systemwould put a great strain on the dispatchingcapability of the uti I ity.

Lack of Inertia in SPS Power Generation. —The frequency stability of a utility system isdirectly related to the rotating mass ormechanical inert ia of i ts col lect ion ofgenerators. It is, in effect, analogous to agiant flywheel kept in motion by numeroussmall driving elements on its rim. Just as aflywheel adjusts only slowly to a suddenremoval or addition of individual drivingelements, the utility network takes severalseconds to adjust to the loss or gain ofmegawatts of power. A generator added tothe system adds additional mechanical iner-t ia as wel l as power. Because the SPSreference design wou [d add power but noadditional inertia, i.e., it might come on orgo off l ine vir tual ly instantaneously, i twould create surges that would be difficultfor the system to accommodate. In order touse SPS-generated power, the utilities wouldhave to develop new modes of ensuring fre-quency stability and control since the pres-ent operating mode depends implicitly onthe mechanical inertia of the system. Onepossibility is to add short-term (15 minutesto 1 hour) battery storage capacity to therectenna. Such an adjustment would add asmal I amount to the cost of SPS power.

Variations in SPS. – Rectenna power outputwou Id vary seasonal Iy because of the eccen-tricity of the Earth’s orbit. As currentlydesigned, the SPS would deliver 5,000 MWwhen the Earth is at maximum distance fromthe Sun. At its closest approach during thenorthern winter, each rectenna will deliverabout 10 percent more power, or 5,500 MW.However, because the variation has a year-Iong period, it would be relatively easy toadjust for it continual Iy.

Short- term variat ions would be muchmore serious. Around the equinoxes, thesatel I ite wou Id I ie in the Earth’s shadow for ashort period each night around midnight.These “eclipses” of the satellite would varytrom a few seconds duration at the start ofthe 31-day eclipse period to a fu I I 72 minutesat the equinox and then decrease again tozero. Because the antenna array wou Id re-qu i re a warmup period of 15 to 60 minutes,outages at the rectenna would vary from 30to 140 minutes. Because the eclipses wouldbe highly predictable and would occur atmidnight in late March and September whenloads are often low (typically 40 to 60 per-c e n t o f t h e p e a k f o r s u m m e r p e a k i n gsystems), they wou Id be unlikely to con-stitute a problem for the system’s reservecapacity. * However, fol lowing the loadswing during the shortest eclipses wouldplace a strain on the ability of the utility torespond because of the need to replace5,000 MW very rapidly unless storage were[n place.

Without short-term storage, the rate atwhich SPS power would decrease during aneclipse would undoubtedly pose controlproblems for the grid. As the satel l i teentered the Earth’s shadow, it would losepower at the rate of 20 percent per minute,too fast for the grid to respond. In general,the maximum power fluctuation a grid canaccommodate is about 5 percent per min-ute. However, it would be possible to shutdown the satellite at an acceptable ratesomewhat ahead of the eclipse.

The satellites and rectennas would requirereplacement or maintenance of numerouscomponents (klystron amplifiers, solid-stateamplifiers, laser components, photocells,dipole antennas, etc.) several times a year.N o r m a l l y t h e o u t a g e s a s s o c i a t e d w i t hroutine maintenance could be scheduledduring periods of low electricity demandand are estimated 22 to constitute a loss of

* I he cfelmands on different utility systems vary regionallyThu\, the truth of this statement must be examined on a reglon-by-r(~glon basis

“ I Grev “Satellite Power System Technical Options and Eco-nomics, ‘ OTA working paper, Solar Power Satelllte Assessment,197’4

Ch. 9—institutional Issues . 241

120 hr/yr of SPS power. Assuming mainte-nance could be scheduled during eclipseperiods, the total time the satellite would beunavailable due to maintenance could beconsiderably less than this.

Boeing 23 has summarized the variouslosses of power to which the referenced SPSmight be subject (table 52). Conspicuouslymissing, however, is the possibi l i ty ofsatellite equipment failure. It will be of con-siderable interest to everyone concerned toi d e n t i f y a s m a n y p o t e n t i a l s o u r c e s o funp/anned SPS shutdown as possible.

Other possible variations in the amount oftransmitted power have to do with the mech-

anism for controlling the position of thebeam on the rectenna, which would be ac-complished by a pilot beam directed fromthe rectenna to the satellite in space. Be-cause of the finite time of travel in space foran electromagnetic signal, the time betweensensing a position error at the rectenna andcorrection of it at the rectenna would beabout 0.2 see, causing an oscillation inpower output at a frequency of 5 Hz. Again,the 5,000 MW nominal output would strainthe capabilities of the utility grid to followthe resultant load variations if short-termstorage capacity were not made a part of theSPS system.

● Power Reception, Transmission, and Distri-bution. –At the rectenna, the power collec-

2“’SPS/Utillty Grid Operations, ” sec 14 of DI 80-25461-3, Boe-ing Corp

Table 52.—PotentiaI for Power Variations From the Reference System SPS

Average Averageduration of Maximum yearly

Frequency of outage per Total power energy Time toRange occurrence occurrence outage reduction loss maximum Scheduled

percent per year minlyr hrlyr GW GW hr power loss Yes No.

Source of powervariation

Spacecraft maintenanceEclipse . . . . . . . . . . . . . . . . . .

o-1oo0-1oo

262

2 X 3,6003,376 total

71 maximumper/occurrence

12056.26

55

1.250.51

0.5

0.4250.3350.290.15

0.250.0005

600281.3

439109.5

1514

10

0.350.280.240.24

0.060.0015

6 min1 min

1 min5 min

10 sec30 min

100 ms

100 mslm

1sI s

0.3 s1s

xx

xEcl ipse wi th shutdown

and startup. . . . . . . . . . . . . .Wind storm. . . . . . . . . . . . . . . . .Earthquake. . . . . . . . . . . .F i re in rectenna sys tem . . . .Meteorite hit of

s p a c e c r a f t e q u i p m e n t .Rectenna equipment

failure . . . . . . . . . . . . . . .Precipitation . . . . . . . . . . . . . . .Pointing error. . . . . . . . . . . . . . .Ionosphere. . . . . . . . . . . . . . . . .Ground contro l

ecluir)ment f a i l u r e . . . .

5,2705,2601,800

840

87.887.63014

75-1oo90-10080-100

0.010.010.01

xxx

90-100 0.01 1,200 20 x

91.5-10093.3-1oo94.8-10098.5-100

5010.6

10

0.8330.8330.8333.32

xx

150

5,00020 x

xx

95-1oo 5 3 0.25Aircraf~ shadow. . . . . . . . . . . . . 99.99-1oo 20 20 m 0.3

1 m maxio c c u r r e n c e

Total without shutdown/startup: 331 hour (3. i’i’Yo) 1,030.8(2.350/~)without shutdown/startup: 362 hour (4.1 20/. ) 1,188.5(2.71 %)

SOURCE: “SPS/Utiiity Grid Operations”, sec 14, D180-25461-3, Boeing Corp.

242 “ Solar Power Satellites

tion system would be divided up into unitsof 320 MW or less. The loss of any one oreven a combination of several power blockswould present few problems for the gridbecause they would be relatively small com-pared to 5,000 MW. Transmission would beover four to five 500 KV lines or eight 345KV lines. The loss of one of the transmissionlines should not affect the stability of thesystem or the operation of the SPS. In theevent of decreased load requirements, someexcess power could be absorbed by therectenna as heat. Sharp drops in power de-mand (e. g., an open circuit due, say, to a lossof several transmission lines) might causeoverheating of the rectenna diodes if thesystem were unable to dissipate the excesspower quickly enough. Hence, protectivemeasures would be required.

Maintenance of the dipole antennas andrectifiers in the rectenna might present a ma-jor expense for the utility. Although themean time to failure is projected to be 30years, 24 this would mean that on the aver-age, 7 to 8 diodes (in the rectifier circuit)could be expected to fail every second, zsleading to an overall failure rate of 3 percentper year. Increased quality control of themanufactured components might mitigatesome of the replacement needs by decreas-ing the failure rate. This procedure, thoughmore expensive per unit, might be less ex-pensive than replacing failed components.

Operating Capacity Factor. – In order tomaximize capital investment, the SPS, if de-veloped, should be operated as close to its“nameplate rating” as possible, i.e., 5,ooOMW. However, during periods of very lightload (e.g., at night during the spring and fall)even current baseload nuclear and coalunits must sometimes be run at less than fu IIcapacity in order to follow the load swing.Such factors would make the real operating

“R Andryczyk, P Foldes, j Chestek, and B Kaupang “SolarPower Satelllte Ground Stations, ” IEEE Spectrum, July 1979,“Satellite Power Systems Utility Impact Study,” EPRI AP-I 548TPS 79-752, September 1980 J C Bohn, j W Patmore, H WFalnlnger

‘5A D Kotin, “Satellite Power System (SPS) State and LocalRegulations as Applied to Satellite Power System MicrowaveRecelvlng Antenna Faclllties, ” DO E-H CPIR-4024-05, 1978

●

capacity of the reference SPS less than itsmaximum capacity, thereby causing it to bemore expensive.

Rectenna Siting. — The land requirements forthe SPS reference system are “large (see ch.8). At 350 latitude the rectenna plus its ex-clusion area would cover an elliptical areasome 174 km2 in extent. By comparison, thecity of Chicago is 57o km2, and Washington,D. C., 156 km2. Finding available land farenough from population centers and mili-tary installations (to make potential electro-magnetic interference sl ight) and nearenough to the load centers to make trans-mission costs acceptable would not be atrivial exercise. Rectenna siting would in-volve the various regulatory agencies andwou Id have to be addressed by uti I ities veryearly in the overal I planning process.

Utilities in far northern latitudes wouldgenerally find siting more difficult becausethe necessary rectenna area and rectennaexclusion area increases with increasinglatitude. Some of the most acceptable loca-tions are in the Southern and SouthwesternUnited States where terrestrial photovol-taics and solar thermal devices will also bemost economic to operate. Offshore sitingwou Id also be possible, though this optionwou Id require extensive study.

The Solid-State Variation

The sol id-state sandwich appears to be moreeconomical to build and place in orbit insmal ler units (about 1 .5 GW),26 mitigating-automatical [y problems arising from the con-trol of 5 GW of power from the referencesystem I n addition, a smaller rectenna wouldmake it possible to place the rectenna closerto load centers or in offshore locations.

Because it is a microwave system, it wouldshare the same stability problems that thereference system wou Id experience.

Laser System

The laser system would present a differentset of challenges and opportunities for the

—) h H a n I ev, op c It


utilities. Because it can generate electricity byemploying infrared radiation to heat a boiler,it could perhaps be used to repower existingcoal, oil, or nuclear facilities. A ground-basedthermal collector would generate steam thatcould be used directly to drive a turbine. In ad-dition, the scale of the proposed satellite/ground system (100 to 500 MW) would fit exist-ing utility capacity quite wel 1. For cases wherethe laser were used for repowering an existingfacility, no new transmission lines would beneeded.

On the other hand, several intrinsic Imitat-ions of the proposed laser system would makeit difficult for the utilities to integrate it intotheir grid:

● Weather Limitations. — Although lasers ofthe overall power and power density ofthe proposed laser system could burnthrough light cloud cover, heavy cloudswould make it unusable. Thus, it would beunsuitable in areas where clouds coverthe region for more than a few percent ofthe year. It might be possible to use it inregions where there are more receivingstations than lasers to support them. Then,if station A were covered by clouds, forexample, the laser feeding that stationcould be redirected to station B that wasunder no cloud cover. The resulting extralaser radiation at station B could then beused to generate more electrical power atthat station to compensate for the loss ofpower at station A, assuming that B hadthe necessary extra capacity. This arrange-ment could work wel I for selected parts ofthe country, i.e., where the likelihood ofcloud cover forming simultaneously overseveral stations was smal 1. However, sincecloudy conditions tend to occur overlarge sections of the Nation at one time,the practicality of this notion would belimited.

Mirror System

A mirror system would be the most highlycentral ized technology of the four a l ter-natives. Its proposers envision a few energyparks in which the increased daylight would be

u s e d t o generate electrical energy — orperhaps, hydrogen. How it might be integratedinto existing uti I ities is unclear. As an electricalsystem, it would require long transmissionlines leading from the energy parks to thepoint of end use. However, hydrogen gen-erated at the site could be transported byvehicles to other destinations.

This concept appears to require a nationalgrid in order to make effective use of the largegenerating capacity of the site (from 10 to 135GW). Stability would be much less of a prob-lem for SOLARE S than for the microwave sys-tem because of the large number of satellitesthat would reflect sunlight, the inclusion ofstorage in the system, and because of the in-dependent blocks of ground-based photovol-talcs or solar thermal plants at the site.

The SO LARES proposal would be subject tosimilar problems with clouds as the laser con-cept. However, the additional radiant energyrnlght be great enough to dissipate clouds thatwould form in the region. For this reason, largemirrors have also been proposed for weathermod i f I( at ion.27

Regulatory Implications of SPS28

Although this area has received only a cur-sory investigation at this time, it is clear thatthe potential for new forms of financial sup-port and management structures for the SPSmight engender new regulatory modes. I n gen-eral, the SPS is I ikely to lead to greater cen-tralization of the Nation’s utility structure,leading in turn to a strong need for coordina-tion between neighboring Public Utility Com-missions or perhaps to completely new struc-tures for regulating utilities.

Local v. Regional Control

Uti l i t ies have general ly entered into agreater degree of cooperation with utilities ino t h e r S t a t e s t h a n h a v e t h e i r a s s o c i a t e dregulatory agencies. This state of affairs will

‘ Va)k, op clt‘“M Cer$ovltz, “Report on Certain Economic Aspects of the

SP~ Energy Program, ” OTA Working Paper, SPS Assessment,1980

244 ● Solar Power Sate//ites

have to change with increasing use of high-capacity generating units and greater grid in-terconnections. A move toward regional plan-ning and control will likely also come aboutbecause of the current dispari ty betweenStates in siting and other regulations, making itmore attractive for utilities to build in Stateswhere regulations are not as stringent or topurchase power from utilities that have asurplus of generating capacity.

In order to regulate their processes, new re-gional regulatory agencies are likely to be setup long before SPS could be part of the utilitygrid, leading to greater grid interties. The in-troduct ion of an SPS w o u l d u n d o u b t e d l yhasten the process because the larger the grid,the more easily outages from a single rectennaor a laser receiver could be handled. Theintermediate-scale sol id-state system would fitinto this kind of structure easily, but a largerscale SPS such as the reference system orSOLARES would necessitate an even morewidespread system than is now envisioned.Although the laser system might be used torepower inter mediate-s i zed generatingfacilities, the ever present possibi l i ty ofmassive cloud cover would require system in-terties in order to make the most efficient useof the available laser satellites.

Site Decisions*

Siting would be a major issue for each oneof the alternative technologies and would alsorequire the development of regional coopera-tion. A major question in SPS siting decisions iswho would have the control; local, State,regional, or national entities? Currently, Stateor local regulatory boards make the ultimatedecisions concerning plant siting. The NuclearRegulatory Commission and the Environmen-tal Protection Agency review these decisions.Except for Federal or State land, the planningfor a 174 km’ rectenna would likely involveseveral local jurisdictions, one more of whoseland use regulations may not be compatiblewith an SPS rectenna. However, if the need forSPS power were great, there might be ade-quate reason to supercede local regulations in

*See also chs 8 and 9, pt C

siting a rectenna. A single 5,000-MW rectennacould serve a large population, one which isvery likely to be distributed across State I ines.Coordination of regulatory authority couldcome from voluntary interstate agreements orfrom federally mandated regional planning.

The current debate about energy parkswould be instructive in identifying and resolv-ing some of these issues. Along with this, thetrends toward regional izing economic controlon energy facilities and instituting a nationalpower grid could provide the institutionalframework for addressing siting issues for arectenna or SOLARE S energy park.

Rate Structure

The magnitude of the capital investmentthat SPS and other future technologies wouldrequire wou Id certainly cause some alterationof the utility rate structure. Just what formthese al terat ions might take is current lyunclear because they depend heavily on theform that the SPS companies would take andhow they might be f inanced.

For example, if the utilities were to own in-dividual SPS plants, they would wish to in-clude their capital costs during construction(current work in progress) in the current ratebase. Most States are presently unwilling toallow this. However, the extraordinarily highcapital costs of other sorts of new generatingcapacity may make this scheme a necessity.(In the other hand, if SPS power were to bebought directly from an SPS corporation andsold to the customer, the concern about add-i n g c a p i t a l c o s t s d u r i n g c o n s t r u c t i o n t o t h e

rate structure would be eliminated for the util-ity regulatory agency and shifted to anothersector of the economy (though they would stillbe reflected in busbar costs).

SPS Corporations and the Utilities.

Currently, the utilities purchase equipmentand knowhow from competing corporationswho build and service generating equipment.Because of the scale of investment necessaryto supply the supportive infrastructure forbuilding an SPS, the SPS corporat ion mightwel I evolve as a monopoly, requ i ring


monopoly-type regulation on the Federal level.Whether generating plants or power are sold, itis likely that the Federal Government wou Id beheavily involved in the regulation of SPS ratesand in siting, reliability, and other aspects ofintegrating the SPS into the utilities’ structure.Such a state of affairs would be likely to leadto a greater degree of centralization of theelectrical industry whether a national powergrid were instituted or not.

General Implications for the SPS

Centralization v. Decentralization

Two opposing forces currently affect theutilities industries— a move towards greatercentralization and an opposite trend towardsgreater decentralization. On the one hand,economies of scale, shared facilities, and thebenefits of regional planning make greatercentralization attractive. On the other, thedesire of individuals, communities, and manycompanies for a greater degree of energy self-reliance for economic or social reasons sug-gests that the utilities will have to adjust to anincreased demand for grid-integrated dispers-ed systems.29 The utilities are just beginning toaddress these issues squarely. Market pres-sures may make dispersed units increasinglymore attractive (see ch. 5, Energy in Context) atthe same time that the Federal Governmentsupports the development of new central tech-nologies. The main issue for the utilities to ad-dress is how to accommodate both ends of thescale in their planning.

Market Penetration

From the point of view of the utilities thatwould either purchase SPS generated powerfor distribution in a grid or purchase receiverinstallations to incorporate directly into theirown systems, the ultimate total volume of SPSgenerated power would depend on a numberof factors in addition to cost. Even if thebusbar cost of SPS electricity was highly com-petitive with other future options, SPS marketpenetration could be limited by reliabilityrequirements and by the technical difficulties

“D Morris and J Furber, “Decentralized Photovoltalcs” OTAWorking Paper, SPS Assessment, 1980

of grid-dispatch that we have already dis-cussed.

● Reserve Requirements. –The criterion thatany two units (e. g., transmission I ine, gener-ating plant, etc. ) in a utility system must con-stitute less than 20 percent of the total sys-tem capacity leads to a minimum size forany single utility system for a given SPScapacity (see Planning Process). Thus, two5,000-MW plants could be accommodatedby a utility system with total capacity of33,000 to 50,000 MW or greater. Smallerutilities’ systems could accommodate ap-p r o p r i a t e l y s m a l l e r SPS plants. But inmaking decisions about whether to proceedwith SPS or not, it is important to estimateh o w m u c h t o t a l SPS c a p a c i t y t h e U . S .utilities grid overall could accommodate.The projected t o t a l c a p a c i t y o f t h ereference system is 300 GW. Could the util-ities grid in 2030 or 2040 accommodate thatcapacity?

Simply scaling up from the individual util-ity or utility grid, using the 20 percentcriterion, 300 GW total SPS capacity implies1,500 CW total electrical capacity in 2030 or2040, about 2‘A times current capacity.

It is clear that under these stringent condi-tions, a low electricity demand would pre-clude development of SPS from the utilitiespoint of view. The 20-percent requirement iscertainly overly stringent, since in effect, itimplicitly assumes that the entire SPS fleetwou Id fail at one time (i. e., no reserve powerwould be available from other utilities). Onthe other hand, satellites that would be sub-ject to eclipse (i. e., all those in geostationaryorbits) would be eclipsed in groups, not sin-gly. For a few days around the equinoxes, ap-proximately 18 satellites would be eclipsedat once. * Roughly speaking this means thata band of Earth some 1,250-miles wide inlongitude would suffer SPS power outage atone time. Thus, there is a distinct limit to theamount of lost generating capacity thatnearby utilities could supply during theeclipse period. Utilities and their regulatorycommissions would only be I ikely to in-

‘A ~atelllte placed at each degree of longitude corresponds to15 ~atel I ltes per hour of time

246 ● Solar Power Sate//ites

●

crease their proportion of SPS beyond the 20percent or so of reserve capacity if theywere consistently able to draw power frombeyond the “shadowed” region, or if theM a r c h / S e p t e m b e r n i g h t p e a k s a r e l o wenough to offset this difficulty. In otherwords, the larger the grid served by SPS thesmaller the reserve capacity that would berequired in any one region.

For the country as a whole then, a 20-per-cent penetration for the reference SPS orany geostationary SPS must be seen as anaverage l imit . Ut i l i t ies with appropriatebackup could accept more. Others, becauseof their size, location, or special needswould only accept less than 20 percent.

A 20-percent penetration of SPS wouldconstitute 120 GW in the low scenario andabout 490 GW in the high one. At a 90-per-cent capacity factor, the contribution ofelectr ical energy from SPS would be 3.2Quads in the low scenario and 13 Quads inthe high scenario (44 percent of the totalelectrical energy consumed in both cases).

Vu/nerabi/ity. –Another aspect of SPS thatthe utilities would certainly investigate incomparison with other generating options isits vulnerability to hostile actions~” (see ch.7), and to unforeseen technical failure.

Of perhaps far more concern to the util-ities would be any vulnerability to technicalfailure (especially common mode failure) orto human error. As noted earlier, the utilitygrid would experience some difficulties inadjusting to planned outages from the ref-erence SPS. Unplanned ones would be farmore difficult to adjust for, though they area common feature of utility operation. Thepotential for unplanned failure of any of thealternative SPS options would only be fullyknown if a decision is made to proceed withone option and a full-scale demonstrationwere built and tested extensively.

Perhaps the most technically sensitivecomponent of the satellite system is the

‘“P Vajk, “The Military Impllcatlons of Satellite Power Sys-tems” NASA/DOE SPS Program Review Meeting, April 1980, Lin-coln, Nebr

beam-focusing apparatus. In the microwavedesign, a pilot beam sent from the rectennato the satellite antenna would control thephasing of the beam transmitters. With theloss of the pilot beam, the SPS power beamwould quickly defocus, a safety feature thatwould prevent accidental or intent ionalwandering of the beam. The laser beamwould be controlled in a similar manner. Itwould be important to design this apparatusto be insensitive to minor perturbations inoperating mode, yet sensitive enough tomaintain its safety qualities. Orientation ofthe reflecting mirrors of the SOLARES sys-tem would be ent irely mechanical andwould be controlled by built-in thrusters. Be-cause the mirror system would be highly re-dundant, the loss of one mirror would not becatastrophic. It would also be essential todesign the SPS to be as free as possible fromhuman error. As the nuclear industry real-izes, designing a technologically complexsystem in which the potential for human er-ror is small is a difficult and complex task.Here again, experience with operat ingsystems wculd be essential to utility accept-ance.

System Comparison

The most acceptable SPS option for the cur-rent utilities to pursue may be the solid-state ora similarly sized microwave. It would providebaseload power with minor weather inter-ference at a scale more in keeping with currentuti I ity practice (i e., 1.5 GW). If future utilitysystems develop the capability and the ex-perience to handle larger increments of gen-erating capacity, an SPS similar to thereference system would be more acceptable,though siting problems might be very great.

The laser and mirror concepts, though offer-ing some interesting potential, suffer fromsevere weather constraints. The possibility thatlaser SPS could be used to repower fossil fuelplant~ wou Id make it of particular interest inregions of relatively low cloud cover. One ofthe significant drawbacks of the mirror con-cept is that it wou Id require the utility andoveral I energy industry to make a radical


change from its current structure because ofits very high degree of centralization (10 to 135GW per site). This would be particularly truefor an SPS system operating in other countrieswhere the grid system is either nonexistent orvery smalI (see ch. 7, International Issues).

Timing of Grid Integration.

If SPS followed the pattern of other newenergy technologies it would take a long timeto be integrated into the utilities structure. Thereference system scenario31 suggests that thefirst SPS could be deliverig power to the gridin about 20 years time. But nuclear power,which has been used for generating steam for30 years, and became an active option for theutilities in 1960 still constitutes only 9 percentof the country’s total capacity (54,000 MW). *

In the face of this past experience, it seemsmore Iikely that the demonstration and testingphases of the SPS would be longer and there-fore involve higher costs than can presently beenvisioned. The utilities are faced with pro-viding reliable power to their customers. Look-ing at SPS from a utilities standpoint, it seemshighly unlikely that the first SPS would be partof the utility grid before 2010.

This estimate is based on technology similarto the reference system technology. Develop-ing a laser SPS might take considerably longerbecause we simply have less experience withhigh-powered lasers. The SOLARES systemwould be technically easier to build, but the in-stitutional and political barriers to creating the

““Satellite Power System Concept Development and Evalua-tion Program Reference System Report, ” op clt

* Nuclear power actual Iy produce~ 13 percent of the electricity

s o l d

associated large energy parks could well slowits development to beyond 2020.

Rate of Implemental ion

The reference system assumes additions of10,000 MW per year to the grid. Assuming elec-tricity demand makes feasible 10,000 MW ad-ditions to U.S. generating capacity, it is unlike-Iy that the rate would begin at that high level.Again, the utilities would want to have con-siderable experience with the first SPS beforethey would be willing to invest in additionalunits. Thus, it is more likely that the annualrate of implementation would begin at lessthan 5,000 MW on the average and build tohigher levels as utilities gain experience and(onfidence in SPS.

Planning for SPS

Acceptance of SPS by the utilities would de-pend on a number of factors, not the least ofwhich would be utility involvement in planningfor SPS. But for the utilities to invest their timeand money in such an effort, they would haveto be convinced that it is worth their while.Thus, SPS must be considered to be economi-calIy, environmentally, and socially accept-able compared with the other future energyopt ions. Much depends on a comparat iveanalysis of the available options. And becausecomparative assessment is necessarily a proc-ess carried out over many years, the utilitiesmust Involve themselves in all phases of thatprocess. A comparative assessment done to-day, though instructive, is as a snapshot com-pared to a motion picture. As we know moreabout each technology in the comparativegroup, the particular parameters will change,leading to a reassessment of the desirability ofeach technology.

ISSUES ARISING IN THE PUBLIC ARENA

SPS Debate

Public involvement in the development oftechnologies has grown significantly in the lasttwo decades. Debate has focused on the en-vironmental. health and safety. economic and

miIitary issues surrounding new technologies,The supersonic transport, nuclear powerplants,PAVE PAWS radar facilities and high-voltagetransmission Iines are examples of technol-ogies that have been subject to recent publiccontrolversy. Since SPS wouId probably be a


federally funded technology (at least in theresearch, development, and demonstration —RD&D phases) with long-term and widespreadramifications, public input in the developmentprocess is crucial, especially in the earlystages. Moreover, the potential effectivenessof public resistance to technological systems,and the public’s interest in direct participationmakes public understanding and approval im-perative for the development of SPS.

The assessment of likely public attitudestowards SPS is difficult, however, because SPSis a future technology. At present, publicawareness of SPS, while growing, is minimal.Even if opinions about SPS were well-formedtoday, it is likely that these attitudes wouldchange with time. Public thinking could be in-fluenced by the other energy and space tech-nologies, perceived future energy demand andgeneral economic and political conditions. 32

The state of SPS technology and estimated SPScosts couId also be important determinants. Inaddition, the degree of public participation inthe SPS decisionmaking process could play apart in future opinions about the satellite.

Most public discussion on SPS has been con-fined to a small number of public interest andprofessional organizations. OTA has drawnheavily on the views of these groups becausethey represent selected constituencies thatcouId play a key role in influencing futurepublic thinking and motivating public action.While OTA cannot determine whether or notthe public would ultimately accept SPS, theseinterest groups can help identify the issues andphilosophical debates that may arise in thefuture.

Interest Groups

A small number of public interest and pro-fessional organizations have expressed theirviews on SPS. In general, many of the indi-viduals and groups that support the develop-ment of SPS also advocate a vigorous spaceprogram. SPS proponents, represented by orga-nizations like the OMNI Foundation, view theexploitation of space in general, and SPS in

“Solar Power Satellite Public (lplnlon l~>ue~ Workshop, ASummary, Feb 21-22, 1980, Office of Technology Assessment

particular, as important means in overcomingterrestrial energy and resource limits.33 To theL-5 Society, which has been the most vocal SPSlobbyist, the satellite system is “a steppingstone to the stars, ”34 an important milestonetowards the society’s goal, the colonization ofspace Groups Iike the Aerospace IndustriesAssociat ion of America 35 and the SUN SATEnergy Counci l , a nonprof i t corporat ionestablished to explore the SPS concept, 36 37

believe that SPS is one of the most promisingoptions available for meeting future globalenergy needs in an environmentally and social-Iy acceptable manner. Professional organiza-t ions such as the American Inst i tute ofAeronautics and Astronautics 38 and the in-stitute of EIectrical and EIectronics Engineers39

support continued evaluation of the concept.

Opponents of SPS characteristically supportterrestr ia l solar and “appropriate” tech-nologies and are often concerned about envi-ronmental issues. The Solar Lobby40 41 and theEnvironmental Policy Center, 42 for example,fear that an SPS program would drain re-sources and momentum from smal l -scale,

—‘‘Iblcf“C Hen$on, A Harlan, and T Bennett, “Concern$ of the L-5

Society About SPS, ” The Final Proceedings oi the ~olar Power%te//lte Pro~ram Review, Apr ,22-25, 1980, DOE, Cent-800491,jUIV 1980 p 542

‘ 5 A e r o s p a c e I n d u s t r i e s A$soclatlon, S t a t e m e n t s u b m i t t e d f o r

the record In So/ar Power ‘5ate//lte, hearings before the Subcom-m Ittee on 5pace Sc Ience and Appl lcatlon~, U S House of Repre-sentatlve~, Mar 28-30, 1979, pp 241-242

‘“P (; Iclwr, “Solar Power Satelllte Development – The NextSteps, Apr 14, 1978, In So/ar Power Sate//lte, hearings before theSub( omrnlttee on Space Science and Appl lcatlon~, U S Houseot Reprewntdtlves, Apr 12-14, 1978, No 68, pp 165-178

1‘I Freeman (ed ) Space .So/ar Power f3u//etln, VOI 1, No 1 and2, SLJNSA T [ nergy Council, 1980

‘“ So/,?r Power ‘$ate//ltes, AlAA Posltlon Paper, Nov 29, 1978,prepared by the AlAA Technical Committee on Aerospace PowerSvstem\, ,]nd the AlAA Technical Committee on Space Systems

‘<’H Brown, “Statement on ‘Solar Power Satellite Research,Development, and Evaluation Program Act of 1979,’” In So/arP~jwer ‘i.~re//lres, hearings before the Subcommittee on SpaceS( Ience dnd Appllcatlons, U S House of Representatives, Mar28- W, 1979, No 15, pp 4-8

“’(’ l tlzen \ E n e r g y Project, S o l a r P o w e r Satelllte$ N e w s Up-

d’]te, Solar Power Satellite Fact Sheet, Coal ltlon Against Satelllte

Power \y\tems Statement (newsle t ters) , 1980

“~ [)(>[ O$S, ‘ Solar Power Satellite, ” Sun T/me\, July 1979, p p4.5

“G C)e Loss , t e s t i m o n y In $o/ar Power Sate//lte, h e a r i n g sbefore the Subcommittee on Space Science and Appllcatlons,U S House of Representatives, Mar 28-30, 1979, No 15, pp109-114

Ch. 9—Institutional issues ● 249

ground-based, renewable technologies. Theyargue that compared to the terrestrial solar op-tions, SPS is inordinately large, expensive, cen-tralized, and complex and that it poses greaterenvironmental and military risks. The Citizen’sEnergy Project has been the most active lob-byist against funding SPS and has coordinatedthe Coalition Against Satellite Power Systems,a network of solar and environmental orga-nizations. 43 Objections to SPS also have beenraised by individuals in the professionalastronomy and space science communitiesthat see SPS as a threat to the funding andpract ice of their respect ive discipl ines.44 45

While there is a wide spectrum of support forSPS in the advocates’ community, rangingfrom cautious support of continued researchto great optimism about the concept viabilityand deployment, almost all opponents objectto Government funding of SPS research, devel-opment, and deployment.

If the SPS debate continues in the future, itis likely that several other kinds of groupswould take a stand on SPS.46 For example, anti-nuclear groups could oppose SPS on many ofthe same grounds that they object to nuclearpower: centralization, lack of public input,and fear of radiation, regardless of kind. Anti-military organizations might also object to SPSif they foresaw military involvement. It is likelythat community groups would form to opposethe siting of SPS receivers in their locality if theenvironmental and military uncertainties werenot adequately resolved or if public participa-tion in the siting process was not solicited.Rural communities and farmers in particularcould also strongly oppose SPS on the groundsthat, like highways and high-voltage power-Iines, it would intrude on rural life.

Issues

The issues that repeatedly surface in the SPSdebate are shown in table 53. It should be

“Citizen’s Energy Project, op. cit.““’’Solar Threat to Radioastronomy, ” New Scientist, Nov. 23,

1978, p. 590.“sPeter Boyce, Executive Officer of the American Astronomi-

cal Society, prwate communication“’Solar Power Satellite: Pubiic Opinion Issues Workshop, A

Summary, Feb. 21-22,1980, Office of Technology Assessment

noted that in most of the discussion, it isassumed that SPS would be a U.S. project (atleast in the near term). If the question of SPSwere posed in an international context, it ispossible that the f lavor of the fol lowingarguments wouId be altered considerably. Cur-rently, public discussion is focused on thequestion of R&D funding. It is anticipated thatas public awareness grows, the environmental,health, safety, and cost issues will receivemore public attention. Questions of centraliza-tion, military implications and the exploitationof space could also be important.

R&D PROGRAMS

The primary purpose of an SPS R&D pro-gram in the near term would be to keep theSPS option open. However, opponents arguethat it makes little sense to investigate thiscomplex, high risk technology when othermore viable alternatives exist to meet ourfuture energy needs.47 In particular, they fearthat SPS would divert funds and valuablehuman resources from the terrestrial solartechnologies, which they perceive as more en-vironmentalIy benign, versatile, less expensiveto develop, and commercially available soonerthan SPS.48 Opponents also argue that a Gov-ernment R&D program for SPS would fall easyprey to bureaucratic inertia, and that no mat-ter what the results of R&D, the programwould continue because the investment andattendant bureaucracy would be too great tostop. 49 Moreover, opponents bel ieve thatpolitical inertia will be generated from therelat ively large amount of money that ispresently allocated to organizations with avested interest in SPS as compared to thosegroups opposed to SPS. In addition, they areconcerned that studies evaluating SPS for thepurpose of making decisions about R&D fund-ing do not compare SPS with decentralizedsolar technologies; they argue that without thiskind of analysis, the public would be unwillingto make a commitment to SPS funding.

“K Bossong and S. Denman, “A Critique of Solar Power Satel-lite Technology, “ INSIGHT, March 1980

48Cltlzen’s Energy Pro}ect, op. cit“Solar Power Satellite: Public Opinion Issues Workshop, A

‘$urrtrriary, Feb 21-22, 1980, Office of Technology Assessment

83-316 0 - 81 - 1 7


Table 53.—Major Issues Arising in SPS Debate*

Pro Con

R&D funding● SPS is a promising energy option ●

● The Nation should keep as many energy options open ●

as possibleŽ An SPS R&D program is the only means of evaluating ●

the merit of SPS relative to other energy technologies

● SPS R&D will yield spinoffs to ether programs ●

SPS is a very high-risk, unattractive technologyOther more viable and preferable energy options existto meet our future energy demandSPS would drain resources from other programs,especially terrestrial solar technologies and the spacesciencesNo matter what the result of R&D, bureaucratic inertiawill carry Government programs too far

cost● SPS is likely to be cost competitive in the energy

market● Cost to taxpayer is for R&D only and accounts for small

portion of total cost; private sector and/or other nationswill invest in production and maintenance

● SPS will produce economic spinoffs

Environment, heath, and safety● SPS is potentially less harsh on the environment than

other energy technologies, especially coal

Space● Space is the optimum place to harvest sunlight and

other resources

● SPS could be an important component or focus for aspace program

● SPS could lay the ground work for space industrializa-tion and/or colonization

● SPS would produce spinoffs from R&D and hardware toother space and terrestrial programs

● SPS is unlikely to be cost competitive without Govern-ment subsidy

● Like the nuclear industry, SPS would probably requireongoing Government commitment

● Projected cost are probably underestimated considerablyŽ The amount of energy supplied by SPS does not justify

the cost.

Ž SPS risks to humans and the environment are poten-tially greater than those associated with terrestrialsolar technologies

. Major concerns include: health hazards of power trans-mission and high-voltage transmission lines, land-use,electromagnetic interference, upper atmosphere ef-fects, and ‘(sky lab syndrome”—

● SPS is an aerospace boondoggie; There are betterroutes to space industrialization and exploration thanSPS

● SPS is an energy system and should not be justified onthe basis of its applicability to space projects

International considerations●

●

●

●

One of the most attractive characteristics of SPS is its ●

potential for international cooperation and ownershipSPS can contribute significantly to the global energy ●

supplySPS is one of few options for Europe and Japan and iswell suited to meet the energy and resource needs ofdeveloping nationsAn international SPS would reduce concerns aboutadverse military implications

SPS could represent a form of U.S. and industrial na-tions’ “energy imperialism,“ it is not suitable for LDCsOwnership of SPS by multinational corporations wouldcentralize power

Military Implications● The vulnerability of SPS is comparable to other energy . Spinoffs to the military from R&D and hardware would

systems be significant and undesirable● SPS has poor weapons potential . Vulnerability and weapons potential are of concern● As a civilian program, SPS would create few military

spinoffs


Table 53.—Major Issues Arising in SPS Debate* —Continued

Pro Con

Centralization and scale● Future energy needs include large as well as small- • SPS would augment and necessitate a centralized in-

scale supply technologies; urban centers and industry frastructure and reduce local control, ownership, andespecially cannot be powered by small-scale systems participation in decisionmakingalone

● SPS would fit easily into an already centralized grid ● The incremental risk of investing in SPS development isunacceptably high

Future energy demand. Future electricity demand will be much higher than . Future electricity demand could be comparable or only

today slightly higher than today with conservation. High energy consumption is required for economic ● The standard of living can be maintained with a lower

growth rate of energy consumption● SPS as one of a number of future electricity sources ● There is little need for SPS; future demand can be met

can contribute significant y to energy needs easily by existing technologies and conservation● Even if domestic demand for SPS is low, there is a • By investing in SPS development, we are guaranteeing

global need for SPS high energy consumption, because the costs ofdevelopment would be so great

———.aArguments mainly focus on the SPS reference system.


Advocates, on the other hand, view SPS as apotentially viable and preferable technology. so

They argue that an R&D program is the onlymeans of evaluating SPS vis-a-vis other energytechnologies. Moreover, if the Nation can af-ford to spend up to $1 billion per year on ahigh-risk technology like fusion, it could cer-tainly afford SPS research that would be muchless expensive.

51 proponents maintain that SPS

research will yield many spinoffs to othertechnologies and research programs whetheror not SPS is ever deployed. 52 53 They also re-

spond to claims of bureaucratic inertia byciting several cases in which large projects,such as the SST and the Safeguard ABM sys-tem, were halted in spite of the large invest-ment. 54 They argue that at the funding levelscurrently discussed for R&D, the risk of pro-gram runaway is very low.

COST

Economic issues have played center stage inthe SPS debate. Almost every journal accountof SPS (part icular ly those cri t ical of thesatellite) has highlighted its cost. 55 56 57 T h e

‘“P. Glaser, “Solar Power From Satellites, ” Physics Today, Feb-ruary 1977,

“Solar Power Satellite: Public Opinion Issues Workshop, ASummary, Feb. 21-22, 1980, Office of Technology Assessment

52P Glaser, “Development of the Satellite Solar Power Sta-tion, ” in So/ar Power from Sate//ites, hearings before the Sub-committee on Aerospace Technology and National Needs, U SSenate, Jan 19,21,1976, pp 8-35

‘IT A Heppenheimer, Co/onies in S p a c e (City, State: stack-pole Books, 1977)

“Solar Power Satellite: Public Opinion Issues Workshop, Asummary, Feb. 21-22, 1980, Office of Technology Assessment.

“J Marinelli, “The Edsel of The Solar Age,” Environrnenta/Ac-tion, July/August 1979,

“R Brownstein, “A $1,000,000,000 Energy Boondoggle; Sci-ence Fiction Buffs Will Love It, ” Critica/ Mass )ourna/, June 1980.

“L Torrey, “A Trap to Harness the Sun,” New scientist, J UIY10, 1980


predominant questions revolve around R&Dpriorities and capital and opportunity costs. Inaddition, the calculation of costs themselvesand cost comparisons between technologiescould be subject to extensive scrutiny anddebate.

Proponents argue that the only cost open forpublic discussion is the cost of RD&D to thetaxpayer. 5859 The bulk of the SPS investmentwould be carried on by the private sector incompetition with other inexhaustible energyalternatives. Furthermore, much of the RD&Dcost could be returned from other space pro-grams such as nonterrestrial mining and in-dustrialization that build upon the SPS techno-logical base. ’” Advocates also contend that anSPS program would produce economic spin-offs by providing domestic employment andby stimulating technological . innovation forterrestrial industry.61 Some proponents alsoargue that as an international system, SPScould lead to the expansion of world energyand space markets. 62 63 In addition, in a globalscenario, the United States would bear a small-er portion of the development costs. Finally,advocates believe that in spite of the large in-vestment costs, SPS would be economicallycompetitive with other energy technol-ogies. 64 65

Opponents argue that the present cost esti-mates are unrealistically Iow. 66 They expectthat like other aerospace projects and theAlaskan pipeline, the cost of SPS would signifi-

5’Solar Power Sate//ite: Pub/ic Opinion /ssues Workshop, ASummary, Feb. 21-22, 1980, Office of Technology Assessment.

“K Heiss, testimony in So/ar Power Sate//ite, hearings beforethe Subcommittee on Space Science and Applications, U SHouse of Representatives, Mar 28-30, 1979, pp 132-158

‘“G. Driggers, letter and statement submitted for the record InSo/ar Power Sate//ite, hearings before the Subcommittee onSpace Science and Applications, U S House of Representatives,pp 407-416

“Glaser, “Solar Power Satellite Development–The NextSteps,” op clt

‘2 So/ar Power Sate//ite: Pub/ic Opinion Issues Workshop, ASummary, Feb. 21-22, 1980, Office of Technology Assessment

“Heppenheimer, op. cit“P. Glaser, “The Earth Benefits of Solar Power Satellites, ”

Space Solar Power Review, VOI 1, No 1 &2, 1980‘5R. W Taylor, testimony in So/ar Power From Sate//ites, pp

48-51.“K, Bossong, S, Denman, So/ar Power Sate//ites or How to

Make So/ar Energy Centralized, Expensive and Environmenta//yUnsound, report No. 40, Citizens Energy Project, June 1979

cantly increase as SPS is developed. Further-more, the U.S. taxpayers would be required tosupport this increase and to maintain an ongo-ing commitment to SPS above and beyond theRD&D costs, just as they have for the nuclearindustry. ” The National Taxpayers Union, inparticular, sees SPS as a “giant boondogglethat will allow the aerospace industry to feedi ts vorac ious appe t i t e f rom the federa ltrough.” 68 Opponents argue that SPS wouldnot a l leviate unemployment substantiallybecause it provides unsustainable jobs to theaerospace sector alone.69 Most opponents alsodo not believe that SPS will be cost com-petitive and argue that the amount of energyproduced by SPS would not justify its large in-vestment cost. 70

The most critical issue for opponents is thequestion of opportunity cost, i.e., the cost ofnot allocating resources for other uses.71 Theyargue that a commitment to SPS R&D wouldjeopardize rather than stimulate the develop-ment of other energy technologies. Opponentsalso argue that SPS might foreclose oppor-tunities for alternate land use, Federal non-energy R&D funding, allocation of radio fre-quencies and orbital slots, resource uses andjobs.

ENVIRONMENT, HEALTH, AND SAFETY

Opponents contend that the environmentalrisks and uncertainties of SPS far exceed thoseof the terrestrial solar options.72 They are mostconcerned about the effects of microwaves onhuman health, airborne biota and communica-tions systems. Critics of SPS also argue that itwould severely strain U.S. supplies of certainmaterials, thereby increasing our reliance onforeign sources. 73 In addition, opponents ques-

—“Solar Power Sate//ite: Pub/fc Opinion Issues Workshop, A

Summary, Feb 21-22, 1980, Office of Technology Assessment“J Creenbaum, National Taxpayers Union, letter to the

Senate Energy and Natural Resources Committee, expressingviews on H R 12505, July 7, 1978

“Richard Grossman, Envlronmentallsts for Full Employment,private communication, July 25, 1979

7“Bos\ong and Denman, op clt7 ’ 50/ar Power Sate//ite Pub//c Opinion Issues Workshop, A

Summary, Feb 21-22, 1980, Office of Technology Assessment7’Citizen’s Energy Project, op clt“] Hooper, Star Gazer’s A/ert, update to “Pie In the Sky”

(newsletter), The Wilderness Society

Ch.. 9—institutional Issues ● 253

tion putting Earth resources in space wherethey cannot be recycled or retrieved. ” Oppo-nents also ci te the large amount of landneeded for receiver siting, high-voltage trans-mission lines, the effects of launches on airand noise quality, the potential for unplannedreentry of LEO satellites (“Skylab Syndrome”),ref lected sunl ight from the satel l i tes andpotential adverse effects on climate and ozoneas serious problems. 75

Advocates, on the other hand, maintain thatcompared to other baseload or large-scaleenergy technologies, SPS would incur less en-vironmental risk. 76 77 78 In particular, itsclimatic effects would be far less severe thanthose of fossil fuels and its bioeffects wouldprobably be much less hazardous than thoseof coal and nuclear. Proponents claim that theprincipal advantage of SPS as opposed to ter-restrial solar and hydroelectric is that it wouldueless land per unit energy.79 Most advocatesare confident that while electromagnetic inter-ference and some atmospheric effects couldbe a problem, acceptable methods can befound to mitigate most of the environmentalimpacts of SPS. Some proponents also arguethat one of the major benefits of SPS is that ittransports to space many of the environmentalimpacts typicalIy associated with the genera-tion of power on Earth. 80 Moreover, air andwater pollution and resource strains could bealleviated if the Nation mined the Moon orasteroids. Some advocates have also stressedthe importance of weighing environmentalconcerns against the needs for inexpensiveenergy. 81 A few contend that while environ-mental issues have ranked high in the publicmind, convenience and the cost of energy are

“DeLoss, “Solar Power Satellite, ” op clt75 Solar Power Satellite: Public Opinion Issues Workshop, A

Summary, Feb 21-22, 1980, Office of Technology Assessment“C laser, “Solar Power Satellite Development–The Next

Steps,” op cltzTHeppenhelmer, oP. c ‘ t

“G. O’Nelll, The High Frontier: Human Co/onies in Space (NewYork William Morrow & Co , Inc , 1977)

7’Glaser, “The Earth Benefits of Solar Power Satellites, ” opcit.

‘“C W Driggers, “SPS Significant Promise Seen, ” The EnergyConsumer, September 1980, pp 39-40

“Solar Power Satellite: Public Opinion Issues Workshop, ASummary, Feb. 21-22, 1980, Off Ice of Technology Assessment

becoming more important. Opponents, on theother hand, contend that environmental con-cerns will remain predominant and that thepublic perception of environmental risks willuItimately dictate costs.

Historically, public involvement in techno-logical controversies has often been spurredby concerns about the environmental risks. En-vironmental issues couId be very important infuture public thinking about SPS as well.82 It isalso Iikely that SPS would serve to bring con-troversies over the impacts of other technol-ogies to the forefront, most notably the bio-effects of microwaves and high voltage trans-mission Iines (60 cycle). While the public mightbe concerned about all environmental impacts(see table 28), those that most immediately af-fect people’s health and well-being woulddominate discussion. Moreover, environmen-t a l i s s u e s w o u l d b e m o s t f o c u s e d a n damplified at the siting stages of SPS devel-opment (see Siting section). Public acceptanceof SPS wilI depend strongly on the state ofknowledge and general understanding of en-vironmental hazards. It will also depend on theinstitutional management of the knowledge;who determines the extent and acceptabilityof the public risk may be just as important asthe data itself.

The most critical environmental issue for thereference system at present is the biological ef-fect of microwaves, not only because the un-certainties are so great, but also because of theexisting controversy over microwave bioef-fects in general. As the proliferation of micro-wave and radio frequency devices has in-creased dramatically, this issue has receivedconsiderable attention in the public arena. Agreat many newspaper and journal articles,83

as well as television segments on 60 minutesand 20/20,84 and Paul Brodeur’s book, The Zap-ping of America: Microwaves, Their DeadlyRisk and the Cover-Up85 signal growing public

“lbld“S Schlefelbeln, “The Invlslble Threat, ” Saturday Review,

Sept 15, 1979, pp 16-2084A Bachrach, Satellite Power System [SPS] Public Acceptance,

October 1978“Paul Brodeur, The Zapping of America (New York W W Nor-

ton & Co Inc , 1977)

83-316 0 - 81 - 18


concern over the increase of “electronicsmog. ”

The press has been particularly suspicious ofthe motives and conclusions of the apparentlysmall, closed community of microwave re-searchers and decisionmakers in the 1950’s and1960’s. Suggestions of vested interests, con-spiracy, and coverups stem from the confiden-tial classification of microwave research byradio frequency users such as the military andthe microwave device industry and the lack ofattempts to solicit public input.86 Whether ornot such motives in fact existed, the public andpress, fearful of the word “radiation,” have ex-pressed little confidence in “official” claimsthat microwaves are as safe as they are pur-ported to be.

The political edge of the scientific con-troversy has also been sharpened by several in-cidents over a 10-year period of microwave ir-radiation of the U.S. embassy in Moscow. Thepeak power of the modulated field was 18microwatt , far below the U.S. guidel ine.8 7

Although neither electronic jamming or sur-veillance seemed to be the purpose of thewaves, there was concern about attemptedbehavior control and health hazards that ledto Project Pandora and other studies. These in-vestigations tended to conclude that the em-bassy workers did not encounter health haz-ards traceable to their exposures.88 Few follow-up studies have been conducted however, andsuspicions still exist. Public opinion seems tohave been influenced by the extensive publici-ty these episodes have received. Articles ques-tioning the ethics and motives of the StateDepartment leave the reader feeling that theissues were never adequately resolved.

Most recently the proposed American Na-tional Standards Institute and National in-st i tute of Occupational Safety and Health(NIOSH) microwave standards have been criti-cized. The Natural Resources Defense Council

‘bIbid.87 Schiefelbein, op. cit.88A. Lilienfeld, et al , Foreign Service Hea/th Status of Foreign

Service and Other Employees From Selected Eastern EuropeanPosts Fina/ Report, Department of Epldemlology, the JohnHopkins University, July 31,1978

(NRDC) claims that the NIOSH criteria docu-ment that will form the basis of the NIOSHstandard, fails to provide a scientifically andmedically sound standard; while it admits theexistence of many low-level effects, it pro-poses a thermal standard and fails to ade-quately address low-level non-thermal ef -fects. 89 NRDC argues that the proposed stand-a rd was a rb i t ra r i l y chosen , jus t l i ke i t spredecessor. N R D C r e c o m m e n d s t h a t t h ecriteria document be recommissioned, that abalanced team of experts work with NIOSHand another review the document and that atemporary emergency standard of 1 mW/cm 2

for 10 MHz to 300 GHz, be promulgated.

In spite of the proliferation of microwaveovens, publ ic resistance to the si t ing oftechnologies that use the radio frequency por-tion of the electromagnetic spectrum has beenstrong and often effective. Local residentshave opposed the construct ion of broad-casting towers and radar installations, as wellas high voltage transmission Iines (ELF radia-tion). (See Siting section.)

SPACE

SPS would represent a giant leap in our pres-ent commitment to space. To some, this spacecomponent and its supporting infrastructurewouId be an unnecessary and expensive com-mitment, 90 while others enthusiastically em-brace SPS as the first step towards an extrater-restrial future for human kind.91 Others arguethat a commitment to space is desirable, butthat SPS would be the wrong route to get there.It is likely that the discussion of the SPS con-cept would precipitate extensive debate overnational priorities, domestic space policy andthe international and military implications ofspace.

Proponents of SPS argue that space is theoptimum place to harvest sunlight92 and otherresources that are needed for an Earth plaguedby overpopulation, resource limitations, and athreatened environment. Many envision a

“ ’ L o u I~ Slesln, le t ter to Dr Anthony Robbins , NIOSH, f r o m

NRDC, j Uiy 11, 19799(’ Cltlzen’s Energy Project, op clt9’Henson, Harlan, Bennett, op clt92 Brownsteln, op clt

Ch. 9—Institutional issues . 255

future in which the U.S. mines, industrializesand colonizes space as a hedge against theselimits to growth.93 94 95 SPS is one step in this vi-sion, for it not only would deliver energy toEarth but would also spur the development ofhardware, management, expertise and energyfor use by other space activities. In fact, someproponents have suggested that without SPS,the space program will atrophy; 96 that SPSwould give NASA a clear context in which toplan other space projects. Some advocates seeSPS, like Apollo, as a way to restore the fron-tier spirit by dispelling the gloom associatedwith limits to growth. 97 98

Many opponents, on the other hand, call SPSan aerospace boondoggle. ” They argue thatSPS, as an energy system, should not be justi-fied on the basis of its applicability to otherspace pro jets. Moreover, it is argued that it isnot necessary to go to space in order to gener-ate technological spinoffs; the Nation can en-courage technological competence and inno-vat ion in more direct and less expensiveways. 100 Some critics of SPS also argue thatSPS would serve to escalate and accelerateconfrontations in space.

In the future, public opinion about spaceand SPS in particular will be influenced by therelative status of space programs in this andother countries.101 For example, the pursuit ofSPS programs in other nations might act as animpetus for the United States to participate inor develop its own SPS. In light of the ex-perience with Skylab, it is clear that the suc-cess or failure of U.S. space projects such asthe space shuttle will have a marked effect onpublic thinking. Grassroots organizations sup-portive of space, and the popularity of sciencef ict ion and space-or iented entertainment,could also play a role in determining attitudestoward the exploitation and exploration of

“Glaser, “Development of the Satellite Solar Power Station, ”op cit

94tieppenhreimer, oP c ‘ t

950’ Neill, op. cit9’Peter Glaser, private communication97Glaser, “Solar Power Satellite Development–The Next

Steps, ” op. cit98 Heppenheimer, oP C’t99 Greenbaum, op cit‘OOOfflce of Technology Assessment, op cit101 Ibid

space. A growing public interest in spaceutilization or exploration and increased ap-preciation of the pragmatic benefits of spacecould put SPS in a favorable light.102 Equitableinternational agreements about the use ofspace could also spur support for SPS. On theother hand, ambiguous space agreements, in-ternat ional conf l icts, or the escalat ion ofspace weaponry couId turn public opinionaway from SPS. Negative public thinkingabout space activities and SPS could also stemfrom the technical failure of a major spacevehicle or satelIite.

INTERNATIONAL CONSIDERATIONS

Beyond its immediate implications as aspace system, there are other internationalissues associated with SPS. The satelIite systemis seen as a possible focus for either globalcooperation or global conflict by advocatesand opponents alike. ’03 However, opponentsare especially skeptical of the feasibility of amuItinational system; they doubt that interna-tional cooperation would occur until most ofthe existing conflicts on Earth are resolved.SPS opponents are most concerned that SPSwould represent U.S. “energy imperialism” bydominating the cultural and technical develop-ment of lesser developed countries (LDCs). 104

Reliance on the industrial nations would im-pinge on third world attempts at energy in-dependence. Furthermore they argue that SPSwouId do Iittle to alleviate the near termenergy needs of LDCs, whereas most terrestrialsolar technologies could. Opponents also fearthat control of SPS by multinational corpora-tions would accelerate the movement of eco-nomic and political power away from individ-uals and communities.105

The characteristic of SPS that is most at-tractive to some proponents, on the otherhand , i s the po ten t i a l fo r mu l t ina t iona lcooperation. 106 107 In fact, a few contend that

‘“l bid‘)’1 bid‘)41 bid‘(’5 Bossong and Denman, “A Critique of Solar Power Satellite

Technology, ” op cit‘l’G laser, “The Earth Benefits of Solar Power Satellites, ” op

Clt‘“7P C laser, “The Solar Power Satellite Research, Develop-

ment and Evaluation Program Act of 1979, ” testimony In So/arPower Satellite, 1979, pp 215-224


this is the only feasible arrangement for SPS;108

a multinational SPS would alleviate many ofthe problems associated with a unilateral SPS,e.g., military implications and high costs. Pro-ponents also argue that SPS would enhancethe economies and industrial development ofLDCs by meeting their primary energy needs.109

They maintain that electricity from SPS couldbe used to produce methanol, transported torural areas in labor intensive pipelines forheating, cooking, and small industries.110 S P Smight also be used for mariculture to providefood. SPS advocates maintain that for oil- andsun-poor Japan and Europe, SPS is one of thevery few energy opt ions avai lable. Somealso argue that the deployment of SPS wouldslow the proliferation of nuclear technology inthe third world. 2

MILITARY IMPLICATIONS

Military issues are intimately related tospace and international considerations. Pro-ponents stress that SPS microwave and mirrorsystems would be ineffective weapons and nomore vulnerable than a terrestr ia l power-plant . ’ While some believe that a militarypresence in space is unavoidable, it is clearthat there are better ways to achieve militarycompetence than with SPS. A primary concernfor opponents is that SPS would provide atechnological base that would further militarycapabilities and serve to escalate military con-f l icts. 114 Many opponents feel that, like theshuttle, military involvement with SPS is inevi-table and that because of its vulnerability, SPSwould accelerate the need for a mil i tarypresence in space. Opponents are also con-cerned that because of their highly centralizednature, SPS satellites and receiving stationswould be targets for attack from terrorists andhostile nations.

[t is likely that the military issue will be ofgreat concern to the public, although it is not

‘08 Glaser, private communication, op clt‘09 Heppenheimer, op cit““D Criswell, P. Glaser, R Mayur, B O’Leary, G O’Neill, and

J Vajk, “The Role of Space Technology in the Developing Coun-tries,” Space So/ar Power Review, VOI 1, No 1 & 2, 1980

1l’Bachrach, op clt1’2Driggers, op cit“’Office of Technology Assessment, op clt1141bld

apparent how the military implications of SPSwould be viewed. For example, a perceivedmilitary potential of SPS and its supporting in-frastructure might be seen as a real benefit to apublic concerned about both national securityand energy needs. 5 Many might even expect amilitary presence in space. The laser systemwould probably engender more concern overmilitary applications than the microwave ormirror designs. Clearly, future opinion will beinfluenced by the state of space weaponry inthis and other nations, future agreementsabout the use of space, and the state of ter-restrial weapons as well as arms limitationsand the perceived mil i tary stature of theUnited States relative to the rest of the world.

CENTRALIZATION AND SCALE

Debate over future energy strategies ofteninvolves questions of general social valuesrather than a narrow choice of specific tech-nologies. One of the issues fundamental to thisdebate is that of centralization of energy pro-duction. The degree of centralization underliesmany of the other issues discussed here in-cluding siting, ownership, public participation,military implications, and the choice betweenterrestrial solar and SPS.

Opponents of large-scale technologies ob-ject to society’s increasing reliance on com-plex technologies and centralized infrastruc-tures that, they argue, tend to erode the viabili-ty of democratic government by concentratingeconomic and political power in the hands of afew, and reducing individual and communitycontrol over local decisions.116 Critics of SPSargue that it would augment and necessitatecentralization by requiring a massive financial-management pyramid.117 Utility, energy, andspace companies and Federal agencies wouldcombine into a simple conglomerate, in whichsmall business would play little or no part.They reason that decisions about local energydevelopment, receiver and transmission linesiting and economic and environmental plan-ning would necessarily be made by Federal

1‘ ‘Ibid‘“Bossong and Denman, “A Critique of Solar Power Satellite

Technology, ” op cit‘‘ ‘Citizen’s Energy Project, op clt

Ch. 9—Institutional Issues Ž 257

and industrial decision makers at a national orperhaps mult inat ional Ievel .118 M a n y o p p o -nents argue that decentralized solar technol-ogies are preferable to SPS because theyemploy a wider range of skilIs, encourage par-ticipation of small firms, are more directly ac-cessible to the individual consumer andequitably allocate their negative environmen-tal impacts to the same people who receive thebenefits. In addition, unlike SPS that must bebuilt in large units to be economic, terrestrialsolar technologies can flexibly accommodatelarge or small variations in energy demand. ’Moreover, unlike SPS, they do not requirelarge contiguous land areas, a large initial in-vestment, large energy backup units or a na-tional utility grid to ensure adequate reliabili-ty. Dispersed energy technologies are also con-sidered more appropriate for lesser developednations because they are better matched toend-use needs, produce relatively small im-pacts on local culture and environment anddon’t require foreign financing, materials,complex infrastructures or hardware. 120 O p -ponents of SPS also view its scale as a severedetriment from an energy planning perspectivebecause the incremental risk of investing in anSPS development program would be unaccept-ably high; a case of “too many eggs in oneb a s k e t .1 2 1

Most proponents of SPS argue that the Na-tion’s energy future will be characterized by amix of centralized and dispersed energy gener-ating systems, but that only centralized tech-nologies like SPS will be able to meet theneeds of industry, large cities, transportationand fuel production. 122 In addition, the cen-tralized nature of SPS facilitates its adoptioninto the existing electricity infrastructure. 123

Some organizational centralization may result,but this will occur in the utility and aerospacesectors, already strongly centralized, and so itwill not cause a significant new concentrationof power.

‘ “Office of Technology Assessment, op clt‘“DeLoss, testimony in So/ar Power Sate//lte, op clt

““Off ice of Technology Assessment, op cit“’DeLoss, “Solar Power Satellite, ” op clt“’Office of Technology Assessment, op clt‘“R Stobaugh and D Yergin, Energy Future (New York Ran

dom House, 1979)

In generaI, advocates of large-scale technol-ogies Iike SPS maintain that centralized sys-tems are more reliable and easier to implementthan dispersed technologies. Central izedpowerplants also produce environmental im-pacts that are localized and hence directly af-fect fewer people. It is argued that dispersedpower generation does not reduce centralizeddecisionmaking; in order to be economic thesesystems will require mass production, stand-ardization, and regulation and an extensivedistribution and service network. 124 Central -ized technologies, at least, are more conve-nient from the user’s perspective. Advocatesalso contend that centralized technologies andinfrastructures are a better means of ensuringequity among the Nation’s citizens.125 For ex-ample, many people, predominantly in the in-ner cities, wilI continue to rely on centralizeddelivery systems because they cannot affordthe capital costs to do otherwise.

While the public might not couch the prob-lem in terms of “centralization, ” it is clear thatpeople will be concerned about technologiesand systems that appear to prevent them fromdirectly influencing the conditions of theirown Iives. 126 Public thinking about SPS willthen be determined by the extent of public par-ticipation in the planning and decisionmakingprocess, experience with central ized anddispersed technologies, at t i tudes towardsenergy, space, and utility conglomerates aswell as the perceived influence and benefits(e g., convenience) of centralized technologies.

FUTURE ELECTRICITY DEMAND

Those in favor of SPS tend to foresee anenergy future characterized by high electricityconsumption and an expanded power grid. 127

Many equate economic well-being to highenergy growth rates.128 Even if the UnitedStates is not able to absorb all of an SPS

“H Brooks, “Critique of the Concept of AppropriateTechnology”, In Appropriate Technology and Social Values — ACr~tlca/ Appraisa/, F Long and A Oleson (eds ) (Cambridge,M,iss Balllnger Publlshlng Co , 1980)

“Offlc P o f Techno logy Assessment , op clt

2’)1 bid

170fflc e of Technology Assessment, The Energy Context ofSP} Work ~hop, A Summary, September 1980

“Off Ice of Technology Assessment, Solar Power Sate//itePublic Op/rrlon Issues Workshop, A Summary, Feb 21-22, 1980


system, they argue that on a global scale therewill always be high demand.129 130 P r o p o n e n t salso argue that if SPS is able to providerelatively cheap, environmentally benign andplentiful energy, then it will be consumed anddemand will be high. ’3’ Some argue that nomatter which demand scenario is finally real-ized, we need to investigate every possibleelectricity option today, so that we have ade-quate choices in the future.

Most opponents, on the other hand, envisionan energy future dominated by conservationand solar technologies. 123 Some believe thatelectricity should play a minor role in ourenergy supply mix because of its thermo-dynamic inefficiency.133 Furthermore, most op-ponents contend that even if electricity de-mand were to increase somewhat, it could besatisfied with existing technologies. 134 T h e yargue that by developing large-scale energysystems such as SPS, we are guaranteeing highenergy use because the investment in theirdevelopment is so great.

Public attitudes about SPS will depend onthe relative cost and availability of energy, theadvancement and proliferation of electricalend-use technologies, attitudes towards energycompanies and forecasters of electricity de-mand, and the sense of energy security asdetermined by domestic supply v. reliance onforeign sources. 35

SPS Technical Options

How might future public reaction to alter-native SPS systems differ? 136 Table 54 iden-tifies some of the relative benefits and draw-backs of the proposed SPS systems as theymight be perceived by the public.

‘2’O’Neill, op cit.‘30Glaser, private communication, op clt‘J IOffice of Technology Assessment, The Energy Context of

SPS Workshop, Op. cltI J21bld

‘“A B Lovins, “Energy Strategy The Road Not Taken?” -Foreign Affairs, October 1976

‘ “Office of Technology Assessment, The Energy Context ofSPS Workshop, op. clt

‘‘sOffIce of Technology Assessment, So/ar Power Sate//ite:Pub/ic Opinion /ssues Workshop, op clt

‘Jblbid

Siting

Histor ical ly , publ ic debate over the in-troduction of a technology has been most pro-nounced at the siting stage. It is during thesiting phase that public opposition to a tech-nology has been most vocal, organized, and ef-fect ive. Cit izens have taken direct act ionagainst the siting of powerplants, airports,prisons, high-voltage transmission lines andmilitary facilities by forming local and na-tional groups, publicizing their cause throughthe media, taking legal action, demonstrating,and occasionally resorting to civil disobedi-ence and violence. 137 In general, siting con-troversies revolve around issues of environ-mental effects, health and safety risks, re-duced land values and fair compensation, pri-vate property rights, opportunity costs, vul-nerabiIity to attack, and public participation inland-use decisions.138 It is clear that in theabsence of national land-use policies, conflictsover land-use priorities will escalate as thepopulation grows, and friction between ruraland urban America and local communities andregional or national decision makers will in-crease ‘‘9

For SPS, siting is a major issue. * SPS wouldbe particularly prone to siting difficultiesbecause of i ts large cont iguous land re-quirements, its potential military implications,and its use of nonionizing electromagneticradiation (e. g., microwaves or lasers) in powertransmission and distribution. This last factoris most important because of considerableuncertainties associated with the environmen-tal and health risks of electromagnetic radia-tion as well as possible interference with elec-tromagnetic systems. These uncertainties and-—- —

‘“L ( aldwell, L Hayes, and I MacWhlrtey, Citizem and the/ nvtronment Case Stucfles in Popu/ar Act/on (Broom lngton, IndI ndlana University Press, 1975)

‘ “OftIce of Technology Assessment, op clt‘ “lbl(l*It ts assumed that SPS receivers would be sited on land Off-

shore locations are also possible and might alleviate many of the~PS Ian(j-use problems, but are not specifically addressed hereAlso not considered here are possible multiple land uses If it canhe shown that land can safely and economically be used foriltlng 5 PS receivers and other uses (e g , agriculture, pastureland) simultaneously, then siting on private land might not be aproblem However, In the absence of detailed assessments on the( osts and environmental Impacts of multiple uses, it IS assumedI n th IS section that I and IS dedicated to SPS receivers alone


Table 54.—Potential Benefits and Drawbacks of SPS Technical Options

Advantages Disadvantages

Laser system. Does not use microwaves ● Possible weapon. Of SPS systems, requires less land area per site and ● Health and safety impact of beam wanders

can deliver smaller units of energy ● Weather modification

Mirror system● Most environmentally benign of SPS systems ● Largest land requirements per site● Least weapons potential of all SPS systems ● Illumination of night sky● Least complex to demonstrate, most immediately ● Weather modification

reliable system . May fall out of low-Earth orbit● Possibly least expensive system

Solid state. Can deliver smaller units of power than mirror or • Microwave bioeffects

reference system ● Electromagnetic interference● Land per site is smaller than mirror or reference

system. Satellites in GEO (in vulnerable to unplanned reentry)

and can be placed over the ocean● Less weapons potential than lasers. Fairly well-developed technology

Reference system● Satellites in GEO (invulnerable to unplanned reentry) . Microwave bioeffects

and can be placed over the ocean • Electromagnetic interference● Less weapons potential than lasers● Fairly well-developed technology


their institutional management have beenresponsible in part for controversies over thesiting of a great many other technologies thatutilize the radiowave spectrum. Community re-sistance to the siting of radar installations,broadcasting towers, and high-voltage trans-mission lines, for example, has been particular-ly strong and unexpectedly effective.

Citizens groups have actively opposed trans-mission lines in a number of States includingOregon, New Hampshire, lowa, and Mon-t a n a .140 As a result of public action in NewYork, the State Public Service Commission hasexpanded the minimum right-of-way for newlines and established an Administrative Re-search Council to study and assess healthrisks.”’ The legislatures of a few New Yorkcounties have adopted resolutions opposingthe construction of 765 KV lines. ’42 In Min-nesota, farmers battled with the public utilities

over the construction of a powerline through8,000 acres of prime farm land. ’43 After attend-ing public hearings and installing solar andwind devices in their homes to reduce their de-pendence on the utilities, some became frus-trated with what they perceived as the un-responsiveness and dishonesty of the utilitiesand finalIy resorted to demonstrations, de-stroying utiIity towers and equipment.

The siting controversies most relevant to theSPS microwave systems are the disputes overthe Navy’s Project SEAFARER (Surface ELF*Antenna for Addressing Remotely-DeployedReceivers), a 25,600-mi 2 underground radioantenna for communication with nuclear sub-marines; and the Air Force’s PAVE PAWS (Preci-sion Acquisition of Vehicle Entry Phased ArrayWarning System), a radar system.’” When theNavy attempted to locate SEAFARER at differ-ent times in Wisconsin, Texas, New Mexico,Nevada, and Michigan, it encountered vehe-

140’’ The New Opposition to High-Voltage Lines, ” BusinessWeek, November 1977

‘41A. Marino and R Becker, “H Igh Voltage Lines. Hazard at aDistance,” Environment, VOI 20, No 9, p 6-15

‘“K Davis, “Health and High Voltage, ” Sierra C/Ub 6u//etin,

JulV 1, August 1978

14’H Nuwer, “Minnesota Peasant’s Revolt, ” Nation, VOI 227,Dec 9, 1978

* E 1 F (extremely low frequency) radio waves’44P Flrodeur, The Zapping of America, Their Deadly Risk and

Cover-[/p (New York W W Norton & Co , 1977)


ment local opposition. Residents in these com-munities were concerned about the health haz-ards of ELF radiation. Ranchers in Texas werealso worried about the effects on livestock.Opponents raised other issues including vul-nerability to nuclear attack, private propertyrights, and decreased land values. 45 Referendadefeated SEAFARER’s construction in severalcounties in Michigan, and in an unprecedentedaction, the Governor of Michigan rejected themilitary program. 146 The Governor of Wiscon-sin also accused the Navy of suppressing en-vironmental impact studies that reportedpossible environmental and health hazards.147

Although the ELF program is still being funded,it has yet to find a new site.

Legal action has also been taken against theAir Force’s plans to build PAVE PAWS in CapeCode, Mass., and Yuba City, Calif.148 Fear ofadverse microwave bioeffects, especialIy long-term, low-level effects, sit at the heart of thecontroversy. While the Air Force stressed thathealth risks were negligible and emphasizedthe need for national security, local groupsargued that the data did not support the claimthat PAVE PAWS will not jeopardize theirheal th. 149

Several key observations can be made fromthese disputes. First, farmers, ranchers, andrural Americans are becoming an increasinglyactive social force working against the intru-sion of urban America on their rural quality oflife. As one OTA workshop participant familiarwith powerline siting controversies remarked,“Developers say that high voltage transmissionlines wouldn’t make any more noise than ahighway would and the reaction of people is‘What do you mean? –That’s why we’re outhere. We don’t want to be near the high-ways’ . . , . (Rural Americans) are sacrificingthe kind of life they are out therefor, for theenergy excesses of urban America.150 In many

‘“c Ellis, “Sanguine/SEAFARE R,” Sierra C/ub Bu//etin, VOI 61,No 4, April 1976

“’Brodeur, op clt1 4 7S Schiefelbein, “The Invisible Threat, ” Saturday Review,

Sept 5,1979, pp 16-20‘40 Brodeur, op cit‘4’S. Kaufer, “The Air Pollutlon You Can’t See, ” New Times,

Mar 6,1978““Office of Technology Assessment, op clt

cases, communities would prefer to leave asite overgrown than consent to any kind ofdevelopment. For SPS as well as other power-plants, dumps, mines, and military installa-tions, siting in remote areas could be a dif-ficult task, especially in parts of the countrywhere residents have already mobi l izedagainst other large-scale projects.151 Accordingto another workshop participant, one farmer,when asked about the SPS proposal , re-sponded, “I’ve had enough. I’m ready to getmy gun out.”152

Another factor that emerges from siting con-troversies is that while concerns over the en-vironmental and health risks of a technologyare very important to nearby residents, thisissue may mask related concerns such as un-sightliness and devaluation of local propertyvaIues 153 that may be more important to theIocal community. For example, in the Min-nesota powerline dispute, the fundamentalissue for many of the farmers was the questionof land-use, i.e., farmland v. right-of -way. ’54However, this issue was channeled into en-vironmental and health concerns that hadgreater political leverage in the courts and towhich the utilities and the general public weremore responsive. While the health effects ofELF radiation were the most frequently ar-ticulated concern of communities opposingSEAFARER, it is clear that to some residents,economics really lay at the heart of the con-troversy 155 These people were primarily con-cerned that Iand values might decrease ifpotential buyers worried about the health ef-fects, and might not have opposed the siting ifthey had been justly compensated. Other resi-dents were most concerned that the presenceof SEAFARER would make their land morevulnerable to mil i tary attack; this wouldthreaten their safety and could also reduce thevaIue of their land.156

‘‘I blci

‘)lbld5‘1 bld

‘“1 bld

“$joseph Thlel, T e x a s S t a t e D e p a r t m e n t o f H e a l t h , p r i v a t e

cc]mmunlcatlon, Nov 28, 1979

‘“P Boffey, “ P r o j e c t S E A F A R E R Critics A t t a c k N a t i o n a l

A( ademy s Review Group,” Science, VOI 192, June 18, 1976, pp121 )-1 21 -i


This second observation also points to thecomplex interrelationship between environ-mental and health risks, costs, land and air use,private property rights, esthetics, and publiccontrol over local decisions. For SPS, it is clearthat the choice of transmission frequency andpower distribution as well as public radiationstandards could have a great bearing on thearea of land that would be required as a bufferzone, the number of people potentially af-fected, compensated, and/or relocated, andhence the cost of developing SPS. In addition,the size of each SPS unit and its location coulddetermine the extent, number and thereforecost of transmission lines that would have tobe sited. The cost of a proposed energy facilitysuch as SPS can also be increased if developersdo not solicit public participation and disputesand court battIes delay construction. Sitingshould therefore be considered as early aspossible in the development process; public in-put is an essential element in the developmentand design strategy.

Finally, it is clear that many of the sitingdisputes might have been resolved earlier andmore easily if the channels of communicationbetween developers and the local community

had been more open. Public participationshould be solicited whenever and whereverpossible, ideally even before the siting stage.Too often, residents become frustrated and re-sentful towards developers and officials whomake inadequate and occasionally dishonest’attempts to involve the public in meaningfuldecisionmaking. This practice has led the pub-lic to seek other forums to voice complaints,thereby delaying decisions and driving upcosts. SPS developers must be well-informedabout the environmental, economic, and mili-tary implications of SPS and shouId arrange foropen dissemination and discussion of that in-formation. In addition, no matter what objec-tive research findings are, public perceptionsof potential hazards are largely influenced bypublic confidence (or lack thereof) in “offi-cial” interpretation of that data (see Environ-ment, Health, and Safety). Whether justified ornot, the public is considerably more cautiousand fea r fu l o f the b io log ica l e f f ec ts o fmicrowaves and other electromagnetic radia-tion than are many representatives of Govern-ment and industry. But until the uncertaintiesare resolved to the public’s satisfaction, thepast cases strongly suggest that local resist-ance to SPS receivers could be substantial.

APPENDIXES

Appendix A

ALTERNATIVES TO THEREFERENCE SYSTEM SUBSYSTEMS

Solar-Thermal Power Conversion

The basic operational principle involved in solar-thermal-electric power systems is identical to thatof virtually al I conventional ground-based power-plants, with a solar furnace replacing the fuel-firedfurnace or nuclear reactor normally used to heatthe power-cycle working fluid. The 10-MW dem-onstration plant at Barstow, Calif., is such a solar-powered thermal cycle. Virtually all componentsof such power systems have been extensively usedand/or tested on Earth, and hence solar-thermalsystems for potential space applications in the SPStime frame would enjoy the availability of a largebody of applicable technology, hardware, and ex-perience. Significant problems are foreseen, how-ever, in reducing the mass and complexity of space-based powerplants to levels that make them com-petitive with the reference system photovoltaicpower source.

The basic rationale for considering thermalpower cycles is their inherently high energy conver-sion efficiency. High-performance thermal cyclepower generators on Earth routinely attain overallefficiencies of more than 40 percent, as comparedwith the 17-percent projected efficiency for the ref-erence-system photovoltaics, and it is quite prob-able that material and component developmentsduring the next decade or two could extend overalloperational thermal-cycle efficiencies for ter-restrial units to over 50 percent. Unfortunately,however, the space environment is such that theseefficiency levels, even with advanced-technologypower-conversion hardware, are extremely difficultto achieve. The fundamental problem is that ofheat rejection; that is, in accordance with the dic-tates of the Second Law of thermodynamics, it isnecessary that any heat engine reject to its environ-ment some of the energy it receives (the ubiquitous“thermal pollution” of Earth-based powerplants).On Earth, effective heat rejection at the low tem-peratures needed for high thermal efficiency isreadily accomplished by using vast quantities ofcool water or air. In space, on the other hand, allheat re jec t ion must be accompl ished so le ly byrad ia t ion, a process that depends on the four thpower o f the rad ia tor ’s temperature. Hence ef f i -cient heat rejection in space can be accomplishedonly at high temperatures, which by the SecondLaw results in reduced thermal efficiency. The radi-

ators of the space-based thermal powerplanttherefore become the key limitation on perform-ance, and counteract the beneficial effect ofpotentially high-cycle efficiency. The most effec-tive space-based thermal power cycle, then, is gen-eralIy the one that minimizes the radiator mass.

The Brayton and Rankine Cycles

The two “simple” solar-thermal cycles con-sidered for SPS are the Brayton and Rankinecycles—the cycles used on Earth for gas turbinesand steam turbines, respectively. In the Brayton cy-cle, a compressor compresses a gaseous workingfluid, that is then heated by solar energy concen-trated into an “absorber” by large, diaphanousthin-film solar mirrors having a concentration ratioof perhaps 2 ,000- to- l , then d ischarges i ts wasteheat to a radiator. It then returns to the compressorand repeats the cycle.

The Rankine cycle utilizes the same basic energysource as the Brayton cycle —typically, a 2,000-to-lsolar concentrator mirror focused on an absorber– but employs a condensable liquid, or, frequently,ordinary steam. The solar energy impinging on theabsorber boils and superheats the steam, whichthen drives a turbine. The steam then condenses inthe radiator at constant temperature. The condens-ed water is then pumped back up to high pressureand forced into the boiler (absorber) to completethe cycle.

The Brayton and Rankine cycle options were re-jected for the reference system, despite theirrelatively high efficiencies, because of the highradiator mass, the lower projected reliability ofrotating machinery, and relative complexity of or-bital assembly operations as compared with thephotovoltaic options. However, recent develop-ments in high-temperature heat exchangers and tur-bines, 1 and particularly innovative designs of heat-pipe and other radiators2 3 now make Brayton-cycleturbines more attractive.

“’Review Study of a 13rayton Power System for a Nuclear Electr!cJpace( raft, j PL contract 955W08, Garrett-AlResearch report No 31-1288A ()( t 9, 1979

‘Yale C F astman, “A Study of the Appl Icatlon of Advanced Heat PipeTechnology to Radiators for Nuclear Spacecraft, ” Thermacore, Inc , Lan-c a~ter Pa E)ec 1, 1975, a I so see Ya Ie C E astm an, ‘‘Advanced Heat PI pes[n Aero$pace Power System s,’ A IAA paper No 77-501, St I. OUIS, Mo , MarI -1, 1977

‘)ohn Hedgepeth and K Knapp, “Preliminary Investlgatlon of a DustRadiator tor Space Power System s,” Astro Research Corp report No ARC-rN 10’14 Mar 1978

2 6 5


Other Thermal Cycles

Other thermal cycles have also been con-sidered, 4 5 to be used independently or in con-junction with the Brayton or Rankine cycles ina combination. The most Iikely prospects arethe thermionic6 7 and the magnetohydrodynamic( M H D )8 c y c l e s or the wave-energy exchang-er. 9 10 11 12 13

None of these seems particularly well adaptedfor use in an independent mode in space, althoughany one of them may have potential when used incombination with either the Rankine or Brayton cy-cle. The primary consideration for these cycles isthe tradeoff between high efficiency and highradiator mass. Principal areas requiring researchand/or additional development are in the high-temperature solar collection and absorption por-tions of all systems and high-performance heat-rejection devices, as well as extensive testing andpilot operations to establish the required levels ofreliability and reductions in cost uncertainties.

Photovoltaic Alternatives

Alternative Materials

Alternative photocell materials considered be-fore selecting the reference system options ofsingle-crystal silicon and galIium aluminure-ars-enide were amorphous silicon, polycrystalline sili-con, cadreium suIfide, copper iridium selenide, andpolycrystalline gallium arsenide. Although all these

‘Daniel L Gregory, “Alternative Approaches to Space-Based PowerGeneration, ” /ourrra/ of Energy 1, March-April 1977, pp 85-92

‘Wllllam P C Ilbreath and Kenneth W Billman, “A Search for SpaceEnergy Alternatives, ” In “Radlatlon Energy Conversion In Space, ” Prog-res~ In Astronaut/c$ & Aeronaut ics , vo/ 61, Al AA, N Y , ] uly 1978, pp107-125

‘G O , Fitzpatrick and E j Brltt, “Thermlonlcs and Its Appllcatlon tothe SPS, ” Ibid, pp 211-221

‘(For example), W Phllllps and J Mondt, “Thermlonlc Energy Conver-sion Technology Development Program, ” Progress report No 630-36 (forJune-September 1978), Jet Propulsion Laboratory, Pasadena, Callf , Nov15, 1978

‘C V Lau and R Decher, “MHD Conversion of Solar Energy, ” In“Radlatlon Energy Conversion In Space, ” K W Blllman (ed ), Progress InAstronautics & Aeronautics, vo/ 61, Al AA, N Y , July 1978, pp 186-200

“Robert T Tausslg, Peter H Rose, John F Zumdleck and AbrahamHertz berg, “Energy Exchanger Technology Applied to Laser HeatedEngines, ” Ibid, pp 465-478

1(’W E Smith and R C Weatherston, “Studies of a Prototype WaveSuperheater Faclllty for Hypersonic Research ‘ report No HF-1056-A-I,contract AFOSR-TR-58-I 58, AD207244, Cornel I Aeronautical Laboratory,Buffalo, N Y , December 1958

“Abraham Hertzberg and Chan-Veng Lau, ‘A High-TemperatureRanklne Binary Cycle for Ground and Space Solar Appllcatlons, ” In“Radiation Energy Conversion in Space, ” K W Blllman (ed ), Progress InAstronautics & Aeronautics, vo/ 61, Al AA, N Y , July 1978, pp 172-185

“Arthur T Mattlck, “Absorption of Solar Radlatlon by Alkali Vapors, ”Ibid, pp 159-171

‘ ‘A jay Palmer, “Radlatlvely Sustained (“eslum Plasmas for Solar E lec-trlc Conversion,” Ibid, pp 201-210

materials cost less than either of the two selectedmaterials, their efficiencies are low and there is lit-tle experience in their production. Other factorsconsidered by the National Aeronautics and SpaceAdministration before selecting the two referencesystem options were total system mass, materialsavailability, susceptibility to radiation damage,development status, manufacturing processes, andenergy payback. Other potential photovoltaicmaterials that were rejected due to obvious pro-blems with one or more of the above factors in-clude selenium and various selenides, cadmiumtelluride, copper sulfide, gallium phosphide, ir-idium phosphide, and a number of higher order in-organic compounds.

Concentration

Another important parameter is the concentra-tion ratio (CR). The selection of CR = 2 for thereference-system gallium arsenide option wasstrongly Influenced by cell temperature considera-tions.14 Should cell technology develop that wouldretain high efficiency at elevated temperatures,higher concentrations might prove cost effective,since both the mass and the cost of reflectormaterials are considerably less than those ofphotocelIs.

There is good experimental evidence that thegallium aluminum-arsenide/gal lium-arsenide cellsselected for the SPS could utilize much higher con-centration ratios to gain higher overall efficiency.There has been considerable development in con-centrating photovoltaic subsystems for terrestrialuse during the past 2 years, and it is possible thatpassive rather than active cooling may be possible.

Multicolor Photocell Systems

Photocells respond to only a part of the avail-able solar spectrum that impinges on them. It ispossible to achieve more efficient utilization of thesolar spectrum by: 1 ) manufacturing a single photo-cell from various materials, each responding to adifferent wavelength band;15 or 2) using separatecelIs, each optimized for a different spectral regionand using an optical system to split the incidentlight into the corresponding spectral ranges.

‘1 W Iame$, and R L Moon, “CaAs Concentrator Solar Cells, ” Pro-cee(lIrtw 01 /he I T th Photovo/talc Specfa/lsts Con fe rence , 1975, pp40,? 408

Richard j Stlrn, “Overview of Novel Photovoltaic Conversion Tech-niq~i IPS at H Igh I ntenslty Level s,” In “Radlatlon Energy Conversion In~pal e K W Blllman (ed ), Progress In Astronautics & Aeronautics, VOIfl / I Uly 1978 pp 136-151

‘‘ I aan, ] url~~on, “Multlcolar Solar Cel I Power System for Space, ’r Ibid,pp 1 5/! 158

Appendix A—Alternatives to the Reference System Subsystems ● 267

Although the technology for both approaches isknown, it is far from having been proved practical,and will require considerable research and devel-opment effort before being considered for futureoperational systems. The second approach appearsto be the most promising in principle. However, itsuffers from a lack of basic data on the photovol-taic materials that might be used for it. Despitetheir attractiveness from the standpoint of effi-ciency, both systems also require either highermass or concentrator systems, which may requireactive cooling. Again, vastly more research isneeded to determine the overall effectiveness ofthese concepts.

Alternative MicrowavePower Converters

I n addition to the klystron, several other devicesmay be capable of converting satellite electricpower to microwaves and transmitting them toEarth. The solid-state amplifier, based on semicon-ductor technology, could result in a significant andbeneficial change of the entire system. The latterserves as one of the four systems considered in thisassessment.

Crossed-Field Amplitier. Thls device in the t e r mof an “amplitron, ” was originally suggested forthe reference system in place of the klystron(linear beam amplifier). Another form of this de-vice, the magnetron, appears to have consider-able merit, * particularly in reducing the spuriousnoise and harmonics generat ion of themicrowave antenna. I n smaller form (1 kW), thisis the familiar unit that powers microwave ovens.The latter devices are reliable and cheap.Whether working devices of the 70-kW capacityneeded for the reference system antenna willprove to be cost effective and possess the re-quired signal characteristics must await designand testing, individually and in a phased array.So/id-State Devices. The principal motivation forconsidering solid-state devices” is their extremelyhigh reliability;17 18 projected failure rates are100 times lower than those of the reference-sys-tem vacuum-tube klystrons or amplitrons.19 Asecondary advantage of solid-state devices istheir potential for lower mass per unit area than

*W C Brown, Microwave Beamed Power Technology ImprovementPT-5613 J PL contract 955-104, May 1980

“ G M Hanley et al , “Satelllte Power Systems (SPS) Concept Deflnl-tion Study, ” First Performance Review, Rockwell International report NoSSD79-0163, NASA MSFC contract NAS8- 12475, Oct 10, 1979

‘nGordon R Woodcock, “SolId-State Microwave Power Transmitter Review, ” Boeing Aerospace Co DOE SPS Program Review, June 7, 1979

‘Vlbid

the vacuum-tube devices. Further, their smallsize and potentially low unit cost facilitate con-venient research and development activities.

The basic problem with solid-state devices istheir low-temperature capability, which implieslow power, coupled with their low-voltage out-put. Additional potential problem areas are un-certain efficiency, current high cost for high-per-formance units, and a host of as yet unresolvedtransmission, control, and power distributioncomplexities.20 However, these devices are stillin the early stages of being evaluated for the SPSapplication, and it is Iikely that studies of the ex-tent devoted to vacuum-tube devices during thepast few years can reduce the present uncertain-ties associated with sol id-state power conversionand transmission.

A major area for concern with the solid-statedevices is the paucity of data and experience onphase control. Although the same generic type ofretrodirective control is projected as for thereference system, much research, analysis, andtechnology advancement will be needed todefine its phase control capabilities to thenecessary level of confidence.

Photoklystrons

The photoklystron combines the principles of aconventional klystron transmitting tube and thephotoemitter in a single device. Sunlight falling ona photoemissive surface generates a current ofelectrons oscillating in such a way as to emit radiofrequency electromagnetic waves. If used on theSPS, the resultant microwaves could be beamed toEarth by using a resonator waveguide.

Potential advantages of the photoklystron overthe photovoltaic array/klystron are that it could in-crease the useful portion of the photoelectricenergy spectrum as compared with photovoltaics(it may reach efficiencies as high as 50 percent21 ascompared with 15 to 20 percent for conventionalphotovoltaics), and that it would greatly simplifythe entire space segment of the SPS22 as comparedwith the reference system, by (a) eliminating thesolar celI arrays altogether, (b) eliminating the needfor on board power distribution, (c) eliminating therotary joint and sliprings, (d) reducing the indi-vidual klystron power and heat dissipation require-ments (there would now be many more klystrons

‘(’lbld‘‘C Ibraeth and Blllman, op c[t

“}ohn W F r e e m a n , Wllllam B Colson and Sedgwick Slmons, “ N e wMethod\ for the Conversion of Solar Energy to R F and Laser Power, ” In

Space ‘danufacturlng 1 I l,’ Jerry Grey and Chrlstlne Krop (eds ) Al AA,New York November 1979


distributed over a much larger area), thereby in-creasing the lifetime of individual klystrons, (e)reducing individual klystron cost, and (f) reducingrectenna area requirements, since the transmittingantenna is much larger than that of the referencesystem.

One suggested system (fig. 10) consists of a largeelliptical array of photoklystrons, constituting thecollector and antenna. A large mirror (that couldalso be a concentrator) would reflect sunlight tothe photoklystrons. Note that even though the mir-ror and antenna must rotate with respect to eachother to maintain proper Sun-facing and Earth-facing attitudes, as in the SPS reference system,there is no need for a mechanical connection be-tween them; in fact, their relative alinement is notat all critical.

Small working models of photoklystrons exist,but have not yet demonstrated any of the systemcharacteristics needed for a practical and cost- ef-fective SPS. Hence the concept still remains justthat: a highly interesting and promising prospectfor further intensive study.

Offshore Rectennas

Because siting a rectenna near the coastal pop-ulation centers that will have most of SPS-gener-

ated baseload electricity may prove extremely dif-ficult, it has been suggested that rectennas belocated in shallow offshore waters. * The costs ofsuch siting would certainly be higher for a givenarea than for comparable land-based sites, but thesystem costs might be cheaper overall because ofcost reductions in rectenna size. The considerablebody of relevant experience that was developed foroffshore airports would be useful for studying thispossibility. The land areas that have been con-sidered for offshore airports are comparable to theneeds of SPS rectennas (e. g., 50 to 20 kmz).

It may be possible to reduce the necessary areaof an offshore rectenna by eliminating most of thebuffer zone and “flattening” the power distributionof the beam across the rectenna. Though potential-ly costly, the option may be taken very seriously bythe European community for whom rectenna sitingon land would prove most difficult. It may also finduses along the shores of densely populated areas inthe United States.

‘Rice Unlverslty, Solar Power Satelllte Offshore Rectenna Study NASACR 1348, November 1980

Appendix B

DECENTRALIZED PHOTOVOLTAIC MODEL

Estimating the busbar costs for a house or in-dustrial plant power station, whether connected tothe grid or stand-alone, may involve somewhat dif-ferent assumptions than for a central power sta-tion. For one thing, the homeowner’s access to cap-ital is different than that of the utility. In addition,the tax liabilities are different and arise from a dif-ferent conceptual framework.

In order to compare most directly the busbarcosts of a decentralized photovoltaic technologywith the centralized terrestrial case and with thesolar power satellite, OTA has adopted the case ofdecentralized systems leased by a utility to an in-dividual owner. The choice to calculate the coststhis way represents neither a preference nor a pre-diction on the part of OTA for the way in which dis-persed photovoltaic systems will be marketed inthe future. The costs so calculated are the costs tothe utility and do not reflect the price to the con-sumer. They therefore are directly comparable tothe busbar costs of electricity from the solar powersatelIite.

For homeowners who would prefer not to con-tinue to rely on a central structure for their power,leasing equipment from a utility may not be an ac-ceptable arrangement. Many, however, will notwish to accept the relatively high capital invest-ment and subsequent maintenance which an installation requires and wilI prefer leasing to pur-chase.

Household and Industrial Photo voltaics:costs and efficiencies

System assumptions:Array efficiency–18 percent*Degradation – 5 percent first year, stable thereafterSystems life– 30 years*Inverterefficiency—90 percentBattery efficiency– 75 percent round tripArray cost — $35 m2*Addit ional installation costs assuming roof replace-

ment — $0.0Addit ional installation costs assuming array f lat on

roof — $1 3/m 2

Additional installation costs assuming array on ground –$80/m2

Operation and maintenance–1 percent of initial costsper year

Lightning protection:Household – $500Industry– $0

Inversion and power conditioning–$82/kW

Battery lifetime (deep cycles) –2,000Battery initial costs ($/kWh capacity)–$49/kWhBattery O&M cost (¢/kWh discharged) –O.038¢/kWhBattery total cost (¢/kWh discharged): 4.3¢/kWhBattery housing and related costs ($/kWh capacity)–

$6.4/kWhBackup generator, residential –$306/kWIndustrial cogenerator steam turbine–$1,446/kWPercent backup in system with storage–60 percent

Sample CalculationThe following equations apply, assuming there

are no variable O&M costs and no fuel costs.Busbar costs (¢/KWh) = Ievelized capital cost/levelized

output + Ievelized fixed O&M/levelized outputLevelized capital cost = FCR X initial capital cost

($/100m2) x 100 ¢/$FCR (fixed charge rate)= CRF (i/N) + T

CRF (i/N) = capital recovery factor = 11-(1 + i) – N

where:I =N =T =

TD =

weighted cost of capitaleconomic life = book lifeIevelized income taxes =(t/(l-t))(CRF( i/N) -1)x P – (TD – 1/N)

tax alIowance for accelerated taxdepreciation**

CRF (i/N) x ((2 x (M – (1/CRF(i/M)))/(M X(M+ 1)X i))

tax lifeM =Levelized output = kWh/year/100m2 arrayLevelized fixed O&M= O&M($/100m2/yr)X1000/$ X

AF(e,i,N)AF(e,i,N) = CRF(i/N) X (1 – ((1 + e)/(1 + i))N)/(i – e)) X

(1 + e)where e = apparent escalation rate (inflation rate)

Financial assumptions:I = 0 . 1 0

t = 0.30e = 0.06N = 30 years for array

= 6 years for batteriesM = 20 years

Example–A household 100m2 array mounted on the roof in

Boston generates 22,017 kWh/yr:Cost of array .$3,500Lightning protection $ 500Power conditioning ., ... $ 650Structural support ., .. $1,300

Total ... ., .$5,950

‘Assumptions of SPS reference system

83-316 0 - 81 - 19

* *A~sume\ sum-of-the-years dlglt~ depredation method

269


O&M costs/year = 1 percent capital costs = $59.56FCR = 0.12504

Levelized capital cost= 0.125 X 5,956 X 100= 74,450 ¢/l00m2/year

Levelized fixed O&M = 9,705 ¢/100m2/year

Busbar costs (¢/kWh) =74,450 + 11,233—— = 3.9¢/kWh22,017 22,017

Appendix C

GLOBAL ENERGY DEMAND FORECASTS

1. IIASA’s predictions were influenced by several factors: 1 ) most of the analysis was done prior tothe 1979 rise in oil prices; 2) there was an optimistic view of the growth of nuclear capacity (tosome 50 to 60 percent of global generating capacity by 2030); 3) participation in the study bythe Soviet Union and other centrally planned economies, who for political reasons projectedvery high economic and energy-use growth rates; 4) low expectations for conservation andalternative energy sources.

2. Predictions of future energy demand are based on estimates of underlying economic anddemographic factors, and of the relation between overall economic and population growth andenergy demand. IIASA’s population and GDP growth rate projections are as follows:

Population projections by region, high and low scenarios (10’ people) (Finite World, p. 429)

Population baseRegion year 1975 Projection 2000 2030

I (NA)-North America 237 284 315II (SU /EE) -Sov ie t Un ion /Eas t Europe . . . . . . . . , 363 436 480Ill (WE/JANZ) -Wes t Europe /Japan , Aus t ra l i a 560 680 767Iv (LA)- Latin America 319 575 797v (AF/SEA)-Southern Africa& Asia .......... 1,422 2,528 3,550VI (ME/NAF)-Middle East/North Africa 133 247 353Vll (C/CPA)-China/Central Planned Asia 912 1,330 1,714World . 3,946 6,080 7,976NOTES: 1975 data are mldyear estlmates from Unlted Nations Monthly Bulletin of Statistics Januar~ 1978

Historical and projected growth rates of GDP, by region, high and low scenarios (percent/yr)

High scenario

Historical Scenario projection

RegionI ( N A )II ( S U / E E ) .Ill ( W E / J A N Z )Iv ( L A )v ( A F / S E A ) .VI ( M E / N A f )Vll (C/CPA)WorldI + Ill (OECD).IV + V(Developing)

1950-603.3

10.45 05.03 97 08.05.04.24 7

1960-75 1975-853 4 4 36 5 5.05 2 4 361 6 25 5 5 89 8 7 261 5 05 0 4 74 4 4.36.5 6.3

1985-20003 34 03 44 94.85.94.03 83 451

2ooo-152 43 52 53 73 84 23 53 02.53 9

2075-302 03 52 03 33.43 83 02 72 03 5

Low scenario

Historical

Region 1950-60I ( N A ) 3.3II ( S U / E E ) . 10.4Ill ( W E / J A N Z ) . 50Iv ( L A ) 5.0v ( A F I / E A ) 39VI (ME/NAf) 70Vll (C/CPA) 8.0World 5 0I + Ill (OECD) 4 2IV + V + VI (Developing) 4 7

1960-753 46 55 26.15 59.8615 04 46 5

Scenario projection

1975-85 1 985-2000 2000-15 2015-3031 2 0 11 1.04 5 3.5 2.5 2 03 2 2.1 1.5 1.24 7 3.6 3 0 3 04 8 3 6 2 8 2 456 4.6 2 7 213 3 3,0 2 5 2 03.6 2 7 1 9 1 73.1 21 1 3 115.0 3 8 2 9 2 6

SOURCE Energy In a F/n/te World, A Global $ystems Ana/ys/s, Energy Systems program croup lnt~matlonal In$tltute for Applied svstems Analvsls (Cambridge,Mass Balllnger Publlshlng Co , 1981) p 431

271


3. In general, the IIASA study places great emphasis on the development of nuclear power, andespecially on an explosive growth in fast breeders after 2000. Although a number of countries,including France, Japan, and the Soviet Union, have announced aggressive plans to installbreeders over the next several decades, it should be remembered that questions still remain asto breeder reactor safety, reliability and operating costs. (See ch. 6 for a comparison ofbreeders and other baseload power sources.) IIASA’s high expectations for breeder develop-ment are by no means universalIy shared.

Percent of global secondary electrical demand met by nuclear power–llASA

1975 2000 – 2030

Low High Low High

Conventional reactors 2 0 271 294 19,2 22.9B r e e d e r s 0.0 044 067 40,6 38,2Total 20 275 303 498 611

SOURCE Energy in a Finlte World, p 580

4. These higher estimates for the amount of coal used for synfuels depend on a number ofassumptions, including the greatly increased use of nuclear power to replace coal in electricitygeneration.

5. The following CONAES study estimates for the U.S. should be compared with the IIASAestimates for North America (see No. 1, p. 271 for population and economic figures; assumeCanadian population is approximately 10 percent of total),

Population in 2070—279 million (Bureau of Census Series I I projection, with no allowance for illegal immigration). z

Average growth in GNP, 1980-2010—2 percent per year ]

Primary energy demand (Quads)CO AfAES4 [United States on/y - 2010)

Low [A] Medium [B] High (C)70 90 130

IIASA 5 (North America-Canada approximately 10 percent of total)2000 2030

Low 99 131H i g h 120 180

Direct comparisons are difficult because of the different time frames and geographical areasexamined. The CONAES A projection, no growth in energy demand over the next 30 years, hasno parallel in the IIASA study. The IIASA low scenario is slightly higher than the CONAES seriesB projections; the high scenario is approximately equal to CONAES C. Population estimates arecompatible; however, CONAES’ 2 percent per year average GNP growth rate is much lowerthan IIASA’s high scenario. It is approximately equal to the low scenario forecast.

Insofar as the two studies are comparable, CONAES’ estimates are somewhat lower thanIIASA’s, with the more radical CONAES A projection much lower. The difficulty lies in deter-mining what this might mean on a global scale. Lower estimates for the United States may holdtrue for other Western industrialized areas, but cannot be extended to developed centrallyplanned economies or to the developing world, where growth rates are expected to be higherthan in the OECD. The CONAES report itself states that: “Even if energy conservation in theUnited States accomplishes a great deal domestically, it will be more than offset by demandgrowth in countries at the ‘takeoff’ stage of development “ Global energy consumption in 2010is estimated to be probably three to four times what it is now, with electrical consumptionrising at even faster rates. b

6. The Case Western Reserve and World Energy Conference estimates for future energy and elec-tricity use are as follows:

‘Energy In Transltlon, 1985-2010 (Washington, D C , National Academy of S, Iences, 1979), p 626z I bid , p 643‘Ibid , p 645‘1 bid , p 668‘Energy In a Ftnfte VVor/d A G/oba/ Systems Ana/ysls, Energy Systems Progr~m Group, I nternatlona I I nstltute for Appl led Systems Analysis

(Cambridge, Mass Ballinger Publishing Co , 1981), p 44o‘Energy In Transition, p 626 )

Appendix C—Global Energy Demand Forecasts ● 273

Energy demand (Quads

20

60

40

20

0

20

40

60

1975 2000 2025/2020

CWRU WEC C WRU WEC

OECD . . . . ... 146.8 3453 266.2 618,8 395.1SU/EE . . . . . . . . . . . . 55.0 98.3 126,1 205.7 235.0D e v e l o p i n g , . . . . , . . . 37.7 103.0 174.0 296,8 434.2Global. . . . . . . . . 239.5 5466 566.3 1,121.3 1,064.3

End-use electricity demand (Quads electric) (estimated by Clav. and Dupas from model data)

1975 2000 2025/2020

CWRU WEC CWRU WEC

OECD ., 12,5 55.8 386 106,9 66.1SU/EE : 3.9 152 216 353 353D e v e l o p i n g . , 1.8 102 135 40.2 465G l o b a l , 18,2 812 737 182,4 1479

Compare these figures to the lower IIASA estimates in figure C-1. The worldwide distributionof LEPP in 2025 for the CWR model is:

Figure C-1 .— Large Electric Powerplants in 2025

160 140 120 100 80 60 40 20 0 340 320 300 280 260 240 220 200 180

F

E

D

c

B

A

a

b

c

d

e

f

8 Nb per zone

“Preliminary Evaluation of Ground and Space Solar Market in 2025, ” 29th IAF Congress, October 1978


7. The World Bank report on Energy in the DevelopingCountries projects energy use and demandover the next decade. From 1973-78, growth in electricity consumption in developing countriesaveraged 8 percent per year, compared to 3.5 percent in developed countries; the Bank es-timates this will continue through the 1980’s. The Bank reports that in 1980 Oil-Importing De-veloping Countries (OIDC) invested $18.5 billion in electric power (70 percent for generation, 20percent for distribution, 10 percent for transmission) out of a total of $24.6 billion invested inall forms of energy—over 75 percent. This is expected to more than double, to $39.7bilIion/year, by 1990.

The amount of installed capacity is estimated to be 241 gW in 1980, rising to 523.7 in 1990.Large increases will be made in gas and nuclear fired generators though absolute levels will re-main relatively low; hydro power will remain the largest single source, at approximately 40 per-cent of the total, with oil generation declining rapidly from 37 to 25 percent. ’

‘Energy In the Deve/op/ng Countrle>, World Bank, August 1980, pp 42-49

Appendix D


DOE Comparative EnvironmentalAssessment

The Department of Energy (DOE) has sponsoredcomparative environmental assessments betweenthe following energy technologies: conventionalcoal (CC), coal gasification/combined cycle (CG/CC), light water reactor (LWR), liquid metal fastbreeder reactor (LMFBR), magnetically confined fu-sion (MC F), central station terrestrial photovoltaics(CTPV), and the reference system solar power satel-lite (SPS). An analysis was performed to quantifyand compare the effects of these technologies onenvironmental welfare (i. e., effects that are notdirectly related to health and safety such as weath-er modification, resource depletion and noise),health and safety and resource requirements. Un-quantifiable health impacts were also identified,but were not ranked (see table D-l). The major con-clusions include:1

With respect to effects on the environmentalwelfare, all of the energy options except forcoal (because of CO2 climatic alterations andacid rain) are roughly comparable in magni-tude, while different in nature.As shown in figure D-1, it is apparent that thequantified public and occupational healthrisks of all the technologies except coal areabout the same in magnitude, but different incause. The health effects that were not in-cluded in this analysis are Iisted in table D-1.Land use comparisons indicate that the landarea required for SPS would be similar to thatfor CTPV. Coal utilizes slightly less total landarea. This is distributed among many mining

‘Program Assessment Report, Statement of Flndlngs, Satell Ite PowerSystems, Concept Development and Evaluation Program, DOE/E R-0085,November 1980

●

●

sites as opposed to the large contiguous landspace needed for SPS and CTPV. The nucleartechnologies require the least total land area.While each technology would encounter ma-terial constraints, none appear insurmount-able. Water requirements are listed in tableD-2.All technologies considered are not energyproducers when operating fuel requirementsare excluded from the calcuIations. Otherwise,only the inexhaustible technologies are netproducers.

Microwaves—Ionosphere Interaction

While only a small fraction of the incidentmicrowave energy is absorbed by the ionosphere,the resultant heating at microwave frequenciescould significantly alter the thermal budget of theionosphere. In the lower ionosphere (D & E regions)a phenomenon called “enhanced electron heating”can occur if the microwave heating overwhelmsthe natural cooling mechanisms of the ionosphere.The resultant heating can then affect electron-ionrecombination rates, changing ionospheric den-sities, or drive additional interactions. Furthermore,in the E region it is possible that the microwaveheating could enhance natural density irregulari-ties called “sporadic E“ that can cause scintilla-tions or scattering of radio frequency signals par-ticularly in the very high frequency (VHF) band,e.g., citizen-band and some television bands. z

New experiments and theories were needed tounderstand the effects of an SPS microwave beamtraveling through the ionosphere (an example of

.—.‘W E Gordon and L M Duncan, “Reviews of Space Science–SPS im-

pacts on the Upper Atmosphere,” Astronautics arid Aeronautics, july/August 1980, VOI 18, NoS 7,8, p 46

Table D.1 .—Unquantified Health Effects”

Solar technologies (CTPV, SPS) Nuclear technologies (LWR, LMFBR, MCF)

Exposure to cell production emissions and hazardous System failure with public radiation exposure (including wastematerials. disposal).

Chronic low-level microwave exposure to the general and Fuel cycle occupational exposure to chemically toxic materials.worker populations (SPS).

Exposure to HLLV emissions and possible space vehicle Diversion of fuel or byproduct for military or subversive uses.accidents (SPS).

Worker exposure to space radiation (SPS). Liquid metal fire (LMFBR, MCF only).

atW unquantified health effects were identified for the coal SYStem used.

SOURCE: Program Assessment Report, Statement of Flnr)vrgs, Satellite Power Systems, Concept Development and Evaluation Program, DOEIER-0085, November 1980.

275


Table D.2.—Water Requirements forAlternative Energy Technologies

Cubic metersTechnology per gigawatt year

Conventional coal. . . . . . . . . . . . . . . . . . . . . . 77x 106

Light water reactor. . . . . . . . . . . . . . . . . . . . . 37x 10’Liquid metal fast breeder reactor . . . . . . . . . 32X 1O6

Coal gasification/combined cycle. . . . . . . . . 14x 106

Magnetically confined fusion . . . . . . . . . . . . 39x 106

Satellite power system. . . . . . . . . . . . . . . . . . = 1 x 103

Central station terrestrial photovoltaics . . . = 1 x 104

SOURCE: Program Assessment Report, Statement of Findings, Satellite PowerSystems, Concept Development and Evaluation Program, DOE/ER-0085. November 1980.

what is called “underdense” heating) becausealmost all of the data generated in the past hasfocused on the “overdense” case, i.e., where theionospheric density is great enough to reflect the in-cident heating frequency.

Two high frequency (HF) ground-based heatingfacilities have been used to simulate SPS heating inthe lower ionosphere. At Arecibo, Puerto Rico,ionospheric physics and heating mechanisms havebeen studied. The Platteville facility in Coloradohas tested the effects on specific radio frequencynavigation and broadcasting systems, namely VLF(3 to 30 kHz, OMEGA), LF (30 to 300 kHz,

LORAN-C), and MF (300 kHz to 3 MHz, AM).3 How-ever, neither Arecibo nor Platteville is equipped togenerate a beam of SPS frequency and power den-sity. Instead the experiments were performed atlower frequencies and power densities and theresults extrapolated to SPS conditions using thescaling law:

P SPS =

P HF——f2 SPS f2 HF

where Psps and PHF are the power of the SPS beam(i.e., 23 mW/cm2) and heating facility beam respec-tively, and f is the frequency of the beam (i. e., fsps

= 2.45 GHz).4 This extrapolation is thought to bevalid only if the primary heating mechanism isohmic (i. e., heating by CoIIisions between ions). Thisassumption has been verified over a limited rangeof frequencies. By increasing the Platteville andArecibo power densities and maximum frequency,confidence in the sealing theory could be im-proved. Experiments are also needed to test the ef-fects of localized ionosphere heating on telecom-munication systems operating at frequencies above3 MHz.

In the upper ionosphere (F region), effects onte lecommunicat ions and on the SPS p i lo t beamstem pr imar i ly f rom a phenomenon ca l led “ ther-m a l s e l f f o c u s i n g ” which results when an elec-tromagnetic wave propagating through the iono-sphere iS focused and defocused as a resuIt of nor-mal variations in the index of refraction. As the inci-dent wave refracts into regions of lesser density,the electric field intensity increases. Thermal pres-sure generated by ohmic heating drives the plasmafrom the focused areas, thereby amplifying the ini-tial perturbation. Although the heated volume inthe D and E regions is confined essentially to thatof the beam, the heated particles in the F regionwiII traverse magnetic field Iines so that large-scalefield-alined striations or density irregularities form.These striations reflect VHF and UHF radiowavesspecularly, causing interference and the abnormallong-range propagation of the signals.

Less is known about the effects of SPS-typeheating in the F region than the D and E layers. Thepower scaling law in the upper ionosphere may dif-fer from that in the lower regions (i.e., the scalinglaw for thermal self-focusing instability may followa 1/f3 dependence rather than the 1/f2 dependencevalid for ohmic heating). Experimental data is

Fnv/ronmental Assessment for the Satell/te Power System – ConceptDevelopment and Eva/uatlon Program – Effects of /onospher/c Heat/rig onTe/ecomm[/n[catlons, DOE/NASA report, DOE/E R 10003-TI, August 1980

‘t nv/ronmenta/ Assessment for the Sate//lte Power System – ConceptDet eloprrrenf and Eva/uat/on Program, DOE/E R-0069, August 1980

Appendix D—Environmentant Health . 277

needed to improve theory and test the effects ontelecommunications.

A single SPS would cause the indicated iono-sphere perturbations within a VoIume approximate-ly equal to the power beam dimensions. For muiti-ple SPS deployments (e.g., the 60 systems definedin the Reference Design) the cumulative effects ofthe perturbed volumes must be determined. Oneimportant question obviously concerns the possi-bility of coupling between adjacent volumes, anddetermining beam separation constraints to elim-inate mutual coupling. 5

The Effects of Space Vehicle Effluentson the Atmosphere

SPS reference system rocket exhaust productswould affect every region of the atmosphere. Intable D-3, the atmospheric effects of most concernare listed. As part of its assessment, DOE has alsoidentified possible means of resolving these uncer-tainties in the event that an SPS program is pur-sued.

Troposphere 6

SPS launch effluents injected into the tropo-sphere could modify local weather and air qualityon a short-term basis. These changes would be dueprimarily to the formation and dispersion of alaunch site ground cloud that consists of exhaustgases, cooling water, and some sand and dust.While sulfur dioxide, carbon dioxide, and carbonmonoxide concentrations would not be significant,nitrogen oxides and water vapor are of concern.

Nitrogen oxides (NOx, especially NO, in theground cloud, might under certain conditions, pre-sent problems for air quality. The projected groundcloud concentrations themselves are not thoughtto violate the short-term national ambient air qual-ity standards that are expected to be promulgatedin the near future, but if ambient concentrationsare already high, a violation could occur. NOX andSOX in the ground cloud could contribute to an in-crease in localized acid rain but this is expected tobe small.

The ground cloud will also contain about 400 to650 tons of water. While having a negligible impacton air quality, water vapor, especially in associa-tion with launch-generated heat and condensation

‘E Morrison, National Telecommunlcatlons and Information Admln-Istratlon, private communlcatlon, Feb 17, 1981

‘Most of this section IS derived from Ertv/ronrnenta/ Assessment for theSatell/te Power $ystem, Concept Development and tvaluatlon Program,DO E/ ER-0069, August 1980

nuclei could have a measurable, although short-term effect on weather. In particular, under certainmeteorological conditions, heat and moisturecould enhance convective activity, and induceprecipitation. While the frequency and degree ofsuch effects are uncertain, none of the projectedweather effects are thought to be serious. Cloud-condensation and ice-forming nuclei would also beproduced in the ground cloud. The effects of thelatter on weather cannot be reliably estimated atthis time. The high abundance of the former in theground cloud is thought to be meteorologically im-portant; cloud-condensation nuclei could changethe frequency and persistence of fog and haziness.It has been suggested that because of the large sizeand frequency of HLLV launches, cumulative ef-fects might occur. More research is needed notonly for SPS, but of weather and climate phenom-ena in general.

Research needs include:●

●

●

●

refine and test ground-cloud formation andtransport predictive models as well as weatherand climate models,update ground-cloud composition as systemsare developed; conduct appropriate observa-tions of rocket launches,study effects on local weather of prospectivelaunch sites including possible cumulative ef-fects, andconsider NOX effects and possible ways toreduce levels given a range of Iikely futurestandard levels and meteorological condi-tions; refine and validate theoretical modelsfor simulating NOx dispersion,

Stratosphere and Mesosphere

The upper atmosphere has received considerablepublic attention in the last decade, largely as aresult of a number of studies examining the effectson the stratospheric ozone layers (which shield theEarth from biologically harmful ultraviolet radia-tion) of the supersonic transport, fluorocarbons,and the biological generation of nitrous oxideetc. 7 8 There is concern that while the potential ef-fects on climate and terrestrial life of altering theupper atmosphere couId be serious, our under-standing of the physics and chemistry of the regionis Incomplete. For example, it is known that thechemical composition of the upper atmosphereplays a key role in maintaining the Earth’s thermalbudget and is directly linked to the dynamics, cir-

The Aero\ol Threat, ” Newsweek, Oct 7, 1974, pp 74-75“( I Imatl( Impact Committee, NRC, Fnv/ronmenta/ Impact of $tra(o-

\phorlr I /IRh/ NAS, Washington, D C 1975


Known

Launch vehicles will inject large amounts ofwater vapor and thermal energy intolocalized regions of the planetary boundarylayer. The potential for inadvertent weathermodification under suitable meteorologicalconditions exists.

Exhaust emissions and reentry productsfrom reference system heavy-lift launchvehicles and personnel orbit transfervehicles will modify ion densities at highaltitudes. In particular, injection of H2O andH2 in the F-region will cause partialdepletion of the F-region.

Ground clouds formed by HLLV launcheswill contain relatively high concentrationsof NOX that, in combination with effluentsfrom sources in the launch site environs,will exacerbate existing air quality problemsunder certain conditions,

HLLV flights will deposit a large amount ofwater and hydrogen above 80 km. Theglobally averaged water content is likely tobe increased by amounts ranging from 8percent at 80 km to factors of up to 100 ormore above 120 km. The injected water andhydrogen will increase the natural upwardflux of hydrogen by as much as a factor of2.

Table D-3.—Atmospheric Effects

Uncertainty

The frequency of occurrence of suitablemeteorological conditions. The extent ofinjection of cloud condensation and ice-forming nuclei. The duration and scale ofthe effects of the nuclei and the thermalenergy inputs. The importance ofanticipated small increases in cloudpopulation, precipitation, haze, and othermeteorological effects to the environs ofthe launch site.

Chemical-electrical interactions in theionosphere, the effectiveness of mitigatingstrategies, and effects ontelecommunications.

Exact value of NO2 air quality standard to beset. Actual ground-level concentrations ofNO2 associated with vehicle launches undervarious ambient meteorological and airquality conditions typical of anticipatedlaunch sites.

The quantitative increases. Whether theglobally averaged increase in water contentwill be sufficient to alter thermosphericcomposition or dynamics in a significantway. Whether the increase will result in achronic, global-scale partial depletion of theionosphere of suff ic ient magnitude todegrade telecommunications. Whether theincreased hydrogen flux will significantlyincrease exospheric density and/or modifythermospheric properties.

Resolution

Design and implement appropriateobservational programs associated withrocket launches and conduct laboratory

Injection of water vapor from HLLV The scale and persistence of the clouds,launches in the altitude range of about 80 especially in view of poorly understoodto 90 km is likely to result in the formation co m p et i n g cooling and h eatingof noctilucent clouds. mechanisms. Whether cumulative effects

could arise and lead to globally significanteffects such as changes in climate

Reference system personnel and cargo orbit Ultimate fate of effluents. Potential impactstransfer vehicles would inject substantial such as increased radiation hazards toamounts of mass and energy into the space travelers, auroral modifications,magnetosphere and plasmasphere. telecommunications, and terrestrial utility

interference, enhanced airglow emissions,and changes in weather and climate.

experiments to characterize better nucleiformed in the combustion of rocketpropellant. Refine, test, and validatetheoretical models suitable for simulatingthe effects of rocket launches. Examine themeteorological conditions appropriate topotential launch sites. Evaluate theimportance of changes in those conditionsto the environs of those sites.

Design and implement experiments aimed atcritical problems. Measure and analyzeinteractions through rocket experimentscombined with telecommunications tests.Apply results to improve theoreticalprediction capabilities. Provide guidance forsystem operational mitigating strategiesand alternatives.

Utilize a range or anticipate probable“standard values” for NO2 including theexisting standard for California. Refine,test, and validate existing modeling tech-niques for simulating formation anddispersion of NO2 in ground clouds. Utilizeexisting and acquire new data related torocket launches for this purpose. Prepare aclimatology of expected NO2 ground-levelconcentrations under a range of meteoro-logical and ambient air quality conditionstypical of anticipated launch sites.

Obtain a better understanding of the naturalhydrogen cycle and develop and implementmodels to simulate the effects of rocketpropellant exhaust on a global scale.

Des ign and implement observationalprograms to obtain data on the occurrenceand characteristics of high-altitude cloudsformed during rocket launches. Improveknowledge of the natural atmosphere nearthe mesopause and develop and implementmodels to better simulate the effects ofwater and hydrogen injection on cloudformation.

Design and implement experiments in themagnetosphere to obtain data for improvingunderstanding of magne tospher i cphenomena of interest and provide systemdesign guidance where appropriate.

SOURCE: Program Assessment Report, Statement of Firrdmgs, Satellite Power Systems Concept Development and Evaluation Program, DOEIER-0085, November 1980.— . — .

culation and climate of the troposphere, but the els 10 One dimensional models predicting globalmechanisms that couple the two regions are ex- average vertical transport of atmospheric constitu-tremely complex and not well understood.9 The ents are used most extensively, although less-refin-SPS assessment relies mostly on theoretical mod- ed two and three dimensional models are also

‘tncyc/oped/a of ‘ic(ence and Technology VOI 1 (New york McCraw-HIII Book Co , 1977] “’~u~ra note b

Appendix D—Environment and Health ● 279

available. High-altitude experiments are needed toimprove atmospheric theory and the data base forthe SPS assessment.

The most significant SPS impacts would arisefrom the injection of rocket effluents, especiallywater vapor and reentry NOX directly into thestratosphere and mesosphere. SPS vehicles emitCO, into the upper atmosphere but the amount isextremely small relative to existing levels and tothe quantities generated by the consumption offossil fuels. The effects of any impurities in therocket fuel, such as sulfur would be negligible.Thermal energy is also injected by HLLV and PLVlaunches, but the effects are thought to be minorand transient.

Increases in water vapor would be of concernbecause its natural abundance in the upper at-mosphere is very low. The most recent estimates in-dicate that the increase in the globally averagedconcentration of water vapor due to 400 HLLVflights per year would be about 0.4 percent in thestratosphere (30 km) and 8 percent in the uppermesosphere (80 km). 2 Increases near the latitudesat which the water vapor was emitted could behigher due to a so-called “corridor effect” with in-creases in water content up to 15 percent above 80km. ” At 120 km and above, it is estimated that theglobal water content could be increased by a fac-tor of 100 or more. 4

The production of nitric oxide from the reentryof HLLVS is expected to increase significantly thenaturalIy occurring NOX concentration and to ex-hibit a pronounced long-term corridor effect in theNOX distribution of the mesosphere. 5 StratosphericNOx levels would also be altered due to downwarddiffusion from the mesosphere, but would be con-fined mostly to the lower stratosphere where theirimpact wouId be negligible.

In the mesosphere, the injection of water couldinduce luminous, thin, or “noctilucent” clouds ofice crystals in the vicinity of the rocket exhaust. Itis estimated that the cloud would expand from asize of 1 to 1,000 km2 over 24 hours. 16 This finding isbased on theoretical calculations and observationsof other rocket launches that deposited far lesswater into the mesosphere than that which is pro-jected for the HLLVS. The clouds are not thought to

‘ ‘ Iblcl‘‘Iblcl‘ ‘Program A~ses\ment Report, Statement oi Finding>, Satelllte Power

Systems Concept Development and Evaluation Program, DOE/NASAReport, DOE/E R-0085, November 1980

“Environmental A$$es$ment for the $ate//tte Power \y$tem – ConceptDevelopment and Eva/ua tlon Program – A tmo~pherlc E ffect$,DOE/E R-0090, November 1980

‘‘Supra note 9“Supra note 6

alter significantly the global climate, but in view ofthe poor understanding of the coupling betweenthe mesosphere and troposphere, this expectationrequires further analysis. A large unknown is the ef-fect of the excess water content on temperaturethat may affect the likelihood and persistence of the clouds. 7

In the stratosphere, detectable depletion orenhancement of the ozone layer from the emissionof water and nitric oxide would be unlikely. Whilewater vapor tends to decrease ozone, nitric oxidetends to increase it. The net effect of SPS referencesystem effluents is thought too small (i. e., either adecrease or increase on the order of 0.01 percent)relative to the natural fluctuations of the ozoneconcentration. 8 This conclusion requires furtherverification as it is based on one-dimensionalmodels.

In addition to the formation of noctilucentclouds and perturbations of the ozone layer, thewater vapor deposited in the stratosphere andmesosphere might contribute to a chronic partialdepletion of the ionosphere. However, this is ex-pected to be very small in comparison to the localdepletions caused by rocket emissions directly intothat region. ’9 Climatic effects might occur fromchanges in the chemical composition of the upperatmosphere, although at present it is not possibleto assess reliably any potential effects. Researchpriorities for SPS upper atmospheric effects in-cIude

●

●

●

●

●

●

●

update emissions inventory and estimates ofreentry NOX;estimate magnitude of corridor effect andstudy possible temperature feedback mecha-nisms;identify and augment existing experimentalprograms to make high-altitude measurementsof water and NOX concentrations, study high-altitude water release data;assess the possibility and climatic impacts ofnoctilucent clouds;develop scenarios of SPS impacts on a numberof different background conditions includingfuture increases of C02;document and verify effects of effluents thatare now thought to have a minor impact on theupper atmosphere; anddetermine telecommunicate ions effect ofchronic, partial depletion of ionosphere (fromwater vapor injected in the stratosphere andmesosphere).

‘Ibid“$u prc? note 9‘5u[)r~ note 6


Ionosphere

The ionosphere is used extensively in telecom-munication systems to propagate and reflect radiowaves. The injection and diffusion of SPS launchpropellants into the ionosphere could alter the den-sity of the electrons and ions that are responsiblefor the unique properties of the ionosphere, there-by degrading the performance of the telecommuni-cations systems. Other effects might also occur,such as enhanced airglow and increased electrontemperature, but the Iikelihood and consequencesof these impacts are yet to be determined. 20

A reliable assessment of the effects of launch ef-fluents on the D-region of the ionosphere cannot bemade at this time. However, two apparently coun-teractive effects have been postulated. z’ The emis-sion of water vapor into the D-region is Iikely todeplete the ionospheric plasma density. This wouldreduce radio wave absorption in the daytime iono-sphere and result in propagation anomalies. On theother hand, NOX, produced by frictional heatingduring reentry, could engender the formation ofions in the D-region. It is believed that enough NOX

would be deposited in the region to compensate forthe reduction of the plasma due to water vapor. Arecent lower ionosphere experiment suggests thatanomalies in the propagation of VLF signals weredue to the effects of rocket effluents. ” While theexperiment was not conclusive, it is clear that de-tectable effects might occur that warrant furtherstudy.

As in the D-region, current understanding of thelaunch effluent effects on the E-region is not veryadvanced. Rocket propellants would be directly in-jected only into the lower E-region because HLLVengines would be shut off at 124 km.23 Some ef-fluents would enter the upper E-region by upwarddiffusion. Exhaust products emitted above the E-region in LEO by PLVS, POTVS and HLLV could alsodiffuse and settle downwards. The impacts of theseeffluents on the E-region, however are very uncer-tain. It is possible that the deposition of ablationmaterials during reentry could augment a radiosignal altering phenomenon called “sporadic E“ inwhich regions of greatly enhanced electron con-centration are created. In addition, the couplingbetween the ionosphere and magnetosphere, the

‘OSupra note 9“ Ibid“C Meltz and J A Darold, “VLF OMEGA Observations of the iono-

spheric Disturbance produced by an Atlas HEAO-C Launch, ” In Pro-ceedings of the Workshop/Symposium on the Prellmlnary Evaluation ofthe Ionospheric Disturbances Associated WIIh the HEAO-C Launch, WithApplfcatlons to the SPS Ertvfronmental Assessment, M Mendlllo and BBaumgardner (eds ), DOE/NASA report Conf 7911108, August 1980

2’Supra note 9

ozone layer, air conductivity, and hence climatecould be affected by the effluents but no reliableconclusions can be made at this time.

The effects of rocket exhaust products are betterunderstood in the F-region, but the impact of SPSeffluents is still not certain. This region isdominated by oxygen atoms that recombine moreslowly with electrons than their molecuIar counter-parts in the lower ionosphere. Exhaust productssuch as water, hydrogen and C02 emitted in the F-region become quickly ionized by charge exchangereactions with the existing atomicions.24 Thesemolecular ions rapidly recombine with the iono-spheric electrons, thereby causing a region of pro-nounced depletion known as an “ionospherichole.” It has been estimated that for each POTVlaunch (which would occur once or twice a month),an ionospheric hole with an area two to three timesthe size of the continental United States25 would beformed and persist for 4 to 16 hours. z’ Each HLLVlaunch (one or two per day) would produce a holeabout one-tenth the size,27 lasting 4 to 12 hours. Ithas been suggested that a long-term low-leveldepletion on the order of 10 percent would developin a ring around the launch latitude as a result ofmultiple launches .28 The probable consequence ofthis depletion ring is a small perturbation of VLF,H F, and possibly VHF wave propagation.

These findings were based on a number of theo-retical models of the ambient and perturbed F-region as well as several observations of rocketeffluent-induced ionospheric holes. The models arefairly well developed and theoretical mechanismsare well understood, but care should be taken inscaling up radiowave propagation effects. Furtherstudy is required in order to predict accurately thelocation, size, movement, and lifetime of the holeas well as the cumulative effects of multiplelaunches. 29 An observation of ionosphere depletioninadvertently took place after a 1973 skylab flightthat produced a hole 1,000 km in radius.30 In 1977,experiments were conducted to purposefulIy pro-duce an ionospheric hole.31 The experiments,named Project LAGOPEDO tended to confirm the

“E Bauer, Proceedings of the Workshop on the Mod/ f/cation of the Up-per Atmosphere by the Sate///te Power System (SPS) Propu/slon Eff/uents,DO E/NA$A Report Conf -7906180

“Supra note 14“Supra note 6‘7 Supra note13‘Ulbld“Supra note 9‘“M Mendlllo, C Hawkins, and J Klobuchar, An Ionospheric Tota/

Electron Content Disturbance Associated With the Launch of NASA$k ylab, Air Force Cambridge Research Laboratories, July 1974

“ Pongratz, et al , Lagoped~Two F-Region Ionospheric Dep/etion Ex-perlment~ Los Alamos Scientlflc Laboratory, LA-U R-77-2743

Appendix D—Environment and Health . 281

theory. Recently, DOE took advantage of thelaunch of NASA’s High Energy Astrophysical Ob-servatory (HEAO-C) by an Atlas/Centaur rocket inorder to monitor the resultant large-scale (1 millionto 3 million km2) effIuent-induced ionospheric hole,which persisted for approximately 3 hours.32 Thepreliminary finding indicates that no severe long-term impacts on HF radio signals occured as aresult, but that VLF transmissions (14 KHz) couldhave been affected.33 On the whole, not enough isknown about SPS-induced ionospheric holes tomake conclusions about their impacts on telecom-mu n i cat ions.

In addition to telecommunication effects, otherpotential effects of SPS rocket effluents depositedin the F-region have been suggested .34 Enhancedairglow emissions could affect astronomy, remotesensing, and surveillance systems. Past observa-tions have noted enhancements on the order of 10kilorayleighs for certain visible and near infraredemissions. 35 The magnitude and significance of SPSairglow emissions warrants further study. The injec-tion of water vapor in the F-region might also per-turb the thermal budget of that region. This wouldincrease the ratio of cooling by radiation andperhaps alter the Van Allen belts and the amountof ionizing radiation in space. Also, as notedpreviously, the number of hydrogen atoms emittedby HLLV launches in the upper thermosphere andexosphere could be comparable to the numbernaturally present. This could increase satellitedrag, alter the Van Allen belts, and affect radiocommunications. The water budget of theseregions is not well understood however, and so theprobability of these effects is not known.

Research should focus on the following areas:●

●

●

●

improve understanding of D&E region effects;refine studies of F-region ionospheric holes inorder to predict location, size, movement, andlifetime;test effects on telecommunications systemsusing D, E, and F regions; andassess airglow effects perhaps with the in-volvement of the remote sensing and astron-omy communities. 36

“M Mendlllo and B Baumgardner, Proceedings of the Workshop/Sum-poslum on the Preliminary Eva/uatlon of the Ionospheric DisturbancesAssociated W/th the HEAO-C Launch, W/th Appl{catlons to the SPS Env/-ronmenta/ Assessment, DOE/NASA Report Conf 7911108, August 1980

“Ibid“Supra note 9‘5 Supra note13‘blbld

Thermosphere and Exosphere

As discussed above in the Stratosphere and Meso-sphere summary, HLLV flights are predicted tosubstantially increase the natural water contentabove 80 km. One consequence of this excesscould be an increase and, perhaps, doubling of theupward flux of hydrogen atoms that result from thebreakdown of the molecular water vapor as well asmolecular hydrogen emitted above 56 km byHLLVS, PLVS and POTVS.37 While it is fairly certainthat an increase in the hydrogen flux would result,the consequences of a perturbed hydrogen cycleare quite uncertain. The hydrogen escape rate intoouter space could increase. Accumulation ofhydrogen above 800 km might also occur, therebypossibly altering thermospheric and exosphericdynamics and enhancing satellite drag.

Research is needed to:. improve understanding of the natural hydro-

gen cycle and dynamic processes of the ther-mosphere and exosphere; and

● design models to quantify hydrogen increasesand simulate SPS effects on a global scale.

Plasmasphere and Magnetosphere

SPS reference system effects on the plasma-sphere and magnetosphere result primarily fromthe emission of COTV argon ions and POTV hydro-gen atoms as the vehicles move between LEO andGEO. 38 The impacts of these effluents could begreat, because the energies and number of ions andatoms injected would be substantial relative to theambient values. Unfortunately, the magnetosphereand plasmasphere are poorly understood. Whilesome potential SPS impacts have been identified asshown in table D-4, their probability and severitycannot be assessed since no experimental data rele-vant to SPS exists for these regions. I n particular,the consequences and the mechanism of interac-tion between the argon ions and the ambientplasma and geomagnetic field must be explored.

In addition to the exhaust products, the satellitesthemselves could also have an impact on the mag-netosphere by obstructing plasma flow, or produc-ing dust clouds, electromagnetic disturbances,space debris, visible and infrared radiation, andhigh-energy electrons.39 Little emphasis has beenplaced on these potential effects, however,because they are thought to be minor and easilyreinedied.

“Supra note 6‘“Supra note 9“lbld


Table D-4.—Satellite Power System Magnetospheric Effects

Effect Cause Mechanism System/activities impacted

1. Dosage enhancement of O + and Ar + in magneto- Thermal heavy ions suppresstrapped relativistic sphere due to exhaust and ring-current-ion cyclotronelectrons plasmasphere heating turbulence, which keeps

electron dosage in balancein natural state

2. Artificial ionospheric Ionospheric electric field Beam induced Alfven shockscurrent induced by argon beam propagate into ionosphere

3. Modified auroral response Neutrals and heavyto solar activity large quantities

4. Artificial airglow 3.5 keV argon ions

5. Plasma density disturbance Plasma injectionon small spatial scale

ions in Rapid charge-exchange lossof ring-current particles

Direct impact on atmospherefrom LEO source

Plasma instabilities

—Space equipment—Modification of human

space activity

—Powerline tripping—Pipeline corrosion (probably

unimportant)—May reduce magnetic storm

interference with Earth andspace-based systems

—Interference with opticalEarth sensors

—Signal scintillation forspace-based communi-cations

SOURCE: Environmental Assessment for the Satellite Power System, Concept Development and Evaluation ProgrammAtrnosptreric Effects, DOEIER-0090,November 1980.

If an SPS program is conducted, it is clear thatthe design of transport vehicles for the outer re-gions of the atmosphere and the environmental as-sessment of their impacts in these regions will beclosely linked. Possible methods of reducing ad-verse effects include the use of both chemical andargon ion engines or an alternative propulsion sys-tem in the COTV, and lunar mining.

Near term studies include:• design and implement experiments in the

magnetosphere and the laboratory to test SPSeffects and increase theoretical understandingof magnetospheric phenomena.

The Electromagnetic Characteristics ofthe Alternative SPS SatelIites

Microwave Satellites

The satellite would generate microwave powerat a frequency of 2.45 GHz or some other centralradio frequency, thermal radiation, and reflectedsunlight at all solar wavelengths. In addition, itwould generate some power at multiples of thecentral frequency (harmonics), and also spuriousnoise on either side of the central frequency.Because the reference system is the only system forwhich an attempt has been made to characterize asystem completely, this report will use itscharacteristics as an illustrative model for allmicrowave systems.

The space antenna would radiate a total of 6,720MW of microwave power towards Earth. The refer-ence system design calls for the power distributionover the face of the satelIite antenna to be gaussianwith a 10-d B taper. The resuIting beam pattern is

shown in figure 40, p. 211. Atmospheric scatteringand attenuation due to absorption, in addition tolosses at the rectenna would reduce the usablepower at the rectenna to 5,000 MW. The followingradiative effects are the most important for thereference system (fig. D-2):

● Out-of-band radio frequency emissions. Thereference system’s klystrons are estimated toradiate energy at the following harmonic fre-quencies: 40

Power levelFrequency (C HZ) (times 6,720 MW)

245- (central frequency) 1490- (second harmonic) -50d B(10-5)7 35- (third harmonic) -90d B(10-9)980- (fourth harmonic) -lOOd B(10 1O)

Although it is known that the antenna pat-terns for these frequencies would be rather dif-ferent from that of the reference system, cur-rent antenna theory is inadequate to predict adetailed spatial pattern.

Spurious sideband noise generation fromthe klystrons outside of the central frequencyis estimated to be no greater than – 200 d B ofthe central frequency at a separation of 8 to 10MHz from the center frequency. Filtering maybe able to reduce this to levels which wouldnot cause appreciable interference in mostcases This is one constraint in the separationnecessary between an SPS frequency assign-ment and the boundaries of the 2.45 GHz In-ternational Scientific and Medical band. Theseconsiderations apply after the klystron tubeshave warmed up. Since, on the average the

——4 ‘C, L) \rndt and L Leopold, “Environmental Conslderatlons for the

MI( rowav(, [learn from a Solar Power Satel I lte, ” I )th /nter\oclety Energy( of)kerslrv) I nglneer~ng ( orrferrwce, San Diego, Callf , August 1978


Figure D-2.–Overview of Potential SPS Electromagnetic=Compatibiiity impacts

noise & harmonics

SOURCE: Power (SPS), Concept Development and Evaluation Program p. 43,

100,000 klystrons in the antenna can be ex-pected to fail at a rate of five per day, out ofband radiation as they fail and as they warmup after being replaced may be greater thanduring their operating period.

The reflected beam at 2.45 GHz, at the har-monics, as welI as at other frequencies gener-ated by the rectenna structure itself, wouldresult in a complicated power spectrum whichwouId change in time as the rectenna ages.The radiation patterns are expected to be 100or broader and partially directive. A capabilityto monitor and locate rectenna intermodula-tion emissions is required to allow timelystructural repair to assure no interference withsensitive terrestrial and aircraft equipment.Optical and thermal emissions. The referencesatellites would reflect sunlight in three major

w a y s 4 1 4 2 1) diffuse reflections from the solararrays, the antenna and the underlying struc-ture; 2) specular mirror-like reflections fromthe solar arrays and the antenna; 3) glints orspecular reflections from the underlying struc-ture. Diffuse reflections would cause eachsatellite to appear as bright as the planetVenus at its brightest phase (magnitude – 4.3).Specular reflections would occur near theequinoxes just at local sunrise or sunset (i. e.,on the same meridian as the satelIite) andwouId cause a 330-km wide spot of Iight sever-al times brighter than the full Moon to sweep

4‘ P A E and M Stokes (eds ), “Workshop on Power Effects on Optical and Radio Astronomy, ” CON F-7905143

(DOE ], I “Apparent 1 of Solar Power Satellites, ”

Power 1980, pp 175190


across the affected area in a few minutes.Glints from components of the satellite’sstructure are not expected to be as serious asthe diffuse or specular reflections and in anyevent, may be significantly reduced or elimi-nated by proper structural design.

In addition to reflecting sunlight, the satel-lite would also emit thermal radiation of anestimated intensity of 6.3 X 10 6 watts p e rsquare meter at the Earth. The precise wave-length peak depends on the details of the char-acteristics of the satellite’s components (e.g.,type of cell, type of antireflection coating,etc. ) but would Iikely fall in the 5 to 10 micronband. The thermal radiation is expected to ex-ceed SIightly current interference levels.

Laser Satellites

As with the other characteristics of laser systems,the electromagnetic characteristics of the lasersatellite are ill defined. However, the followinggeneral radiation effects can be expected. Quan-t i ta t ive data wi l l be ava i lab le o n l y a f t e r t h esystems become more highly defined.

In general, laser systems would reflect sunlightfrom the laser platform and from the relay mirrorsin LEO and CEO, if any. I n addition, they wouIdradiate thermal energy, most probably in the 5 to10 micron region of the infrared. They would alsobe detectable as a thermal source of microwavepower.

● Reflected sunlight. The brightness of Iaser sat-ellites at CEO or LEO would depend on themode of power CoIIection and conversion (e. g.,photovoltaic or direct solar pumped) and theoveralI size of the satellite. OpticalIy, the mostimportant differences are that the LEO satel-lite would be brighter and perceived as mov-ing slowly by terrestrial observers.

Because they would be smaller than the ref-erence system satellites, individually theywould also be less bright. However, there willbe more of them. (If laser satellites could bemade to operate with the same efficiency asthe microwave designs, five 1,000-MW or ten500-MW satellites would be needed to equalreference system capacity. ) Laser relay mirrorsin LEO and GEO would contribute both sta-tionary and moving sources of light. However,because of their small size (several meters),they are not expected to be readily visiblefrom Earth.

● H e a t radiation. Because an appreciableamount of the sunlight which is intercepted bythe laser satellite would be absorbed and re-emitted as heat, the satellite, whether in CEOor LEO, would be a diffuse infrared radiatorand would radiate some energy at microwavefrequencies as well.

• Laser beam characteristics. The two major pres-ent laser alternatives operate near 5 microns(CO laser) or 10 microns (CO2 laser) infraredwavelengths. Because the beams are highlydirective, they would be only slightly observ-able in the infrared except for receivers placedvery near the laser ground stations. Scatteredlight from the beam would be detectable inthe lower part of the atmosphere.

Mirror Satellites

Because the mirrors are designed to reflectsun Iight only, their emissions wouId be only sIightlyaltered from the original solar spectrum (i. e., theywouIdn’t radiate appreciable infrared or micro-wave radiation). Those emissions would be large,however, for the ground base into which the sun-light is directly reflected (i.e., the equivalent of oneSun).

● Terrestrial observers away from the groundsite would see moving patches of light about0.5 min arc across surrounded by an aureole ofscattered Iight. The precise apparent bright-ness of the mirrors wilI depend on a number offactors, e.g., the orientation of the mirror withrespect to the observer, the relative position ofthe Sun from both the mirror and the observer,the albedo of the reverse side of the mirrors,and the atmospheric conditions above theground station. Low-intensity scattered sun-light from aerosols and dust high in the at-mosphere would be observable at up to 150km from the ground station.

The Interaction Between BiologicalSystems and Electromagnetic Waves

Microwave radiation is a form of electromag-netic energy which is used in numerous commer-cial, industrial, military, and medical devices in-cluding microwave ovens, radar, diathermy equip-ment, and sealing instruments. The microwaveband accounts for frequencies ranging from 300MHz to 300 GHz,


The extent and consequence of exposure ofbiological systems to microwaves depends on thefollowing characteristics of the incident energy,the biological organism, and surrounding environ-ment:43

● Frequency of electromagnetic radiation. — T h efrequency of radiation is the number of com-plete oscillations per second of an electromag-netic wave. The energy of the radiation isdirectly proportional to the frequency. Al-though the frequency of microwaves is high, itis not high enough for the quanta to ionize,i.e., to eject an electron from a molecule oratom; hence microwaves are called “nonioniz-ing. ” The bioeffects of X-rays and other ioniz-ing radiation are known to be more severethan those resulting from the nonionizing por-tion of the spectrum.

The frequency also determines the depth ofpenetration when an electromagnetic wave isincident on biological material. I n general, thelower the frequency, the greater the depth ofpenetration. For example, infrared waves pen-etrate no deeper than human skin, whereas mi-crowaves (which are lower in frequency) pen-etrate through the skin and fat and into humanmuscle. 44 The relationship between frequencyor wavelength (frequency is inversely propor-tional to wavelength) and the size of the irradi-ated body is also important. Resonance (i. e.,most efficient absorption) will occur when thelength of an organism measures approximatelyhalf of a wavelength of the incident elec-tromagnetic field. For example, the resonancefrequency at which the absorption rate is max-imized for the male human body is on theorder of 70 to 100 MHz, whereas the maximumabsorption rate for rats occurs at 2.45 GHz.45

Thus, an electromagnetic wave may elicit avery different response from organisms of twodifferent sizes (assuming that the amount ofenergy absorbed is the dominant determinantof a biological response).

Understanding of the functional depend-ence of bioeffects on frequency is not com-

‘ ‘For a more detailed discussion of the biophysics of microwave inter-actions with blologtcal systems, see S Baranskl and P Czelskl, i310/oglca/Effects of Microwaves, Dowden, Hutchlnson and Ross, Inc , Pennsylvania,1976

“R D Phllllps, et al , Comp//atlon and A$$e$\ment of Microwave BIo-e f fec ts A Se/ect/ve Rev/ew of tfre L Iterature on the Blo/og)ca/ L ffectj ofMicrowaves In Re/at/on to tfre $ate///te Power $y~tem ($P\), final report,DOE/NASA, May 1978

“E Berman, “A Review of SPS-Related Microwaves on Reproductionand Teratology”, I n The Flna / Proceedings of the $o/ar Power Sate///te Pro-gram Rev/ew, Apr 22-25, 1980, DOE/NASA report Conf -800491, July1980

●

●

●

●

plete. The existence of frequency windows,i.e., effects observed over one specific rangeof frequencies is not well-understood.Intensity of incident wave. –The energy car-ried by an electromagnetic wave per unit areaand time is called its power density and ismeasured in units of milIiwatts per square cen-timeter (mW/cm2). Heating or thermal effectsare generally thought to occur at power den-sities greater than 10 mW/cm2. Effects at muchlower power densities have been postulatedbut the existence and consequence of “non-thermal” phenomena remains in dispute. Pow-er density windows have been observed ex-perimentally in which bioeffects are notedonly over a specific range of power densitiesand not above or below.

Recently, the microwave community hasadopted the specific absorption rate (SAR) as ameasure of the energy absorbed by a biologi-cal organism. The SAR is expressed in units ofmilliwatts per gram (mW/gm). It is a functionof the power density and weight of the ir-radiated organism. While the SAR providesmore information about the bioeffects ofmicrowaves than it does of the power densityalone, it cannot be used to entirely predict theeffects of exposure to microwaves. The SAR isaveraged over the entire body; it does not con-sider energy absorbed differentially in specificbody parts. It also does not account for possi-ble nonthermal effects. Furthermore, it doesnot measure the “biological effectiveness” ofa microwave, i.e., its ability to induce an effectwhich is dependent on parameters such as therelation between the frequency and size ofsubject or body part.Duration of exposure. – For thermal effects,the length of exposure may influence thebody’s ability to cool. Heating resulting fromlong duration exposure of high-intensity wavesmay overwhelm the natural cooling system. Atlower power densities, i.e., “nonthermal”levels, the cumulative or long-term effects arenot known.Waveform. – It is thought that the biologicalconsequences of exposure to continuous waveradiation is usually less severe than from thatwhich is pulsed or modulated, although basicappreciation of the mechanisms of interactionis lacking,Subject characteristics. – Bioeffects are spe-cies-specific, primarily because the factorswhich determine energy absorption such assize, structure, body, insulation, and heat dis-

83-316 0 - 81 - 20


●

sipation, and adaptive mechanisms vary withspecies. The composition and geometry of bio-logical matter also determine the depth ofpenetration and wave characteristics; tissue,muscle, and fat each exhibit different dielec-tric and conductive properties. Thus, withoutadequate theories of interaction, extrapola-tions from animal studies to human bioeffectsare extremely difficult. The sex, age, and stateof health of an irradiated subject may also bean important factor, since size and suscep-tibility to certain kinds of effects may differwith respect to these parameters. It also ap-pears that electromagnetic radiation may actsynergistically with drugs. The differential ab-sorption of energy may result in hotspots. Thisrelatively increased energy deposition in cells,organs or parts of the body relative to its sur-roundings could lead to very specific biologi-cal effects after exposure.

The orientation of the organism with respectto the electric field component of the wave isalso important —the most energy is absorbedwhen the electric field is parallel to the longaxis of the body. In animal experiments, phys-ical restraints or sedation might influencestudy results. Measurement devices such asimplanted probes could also alter the fielddistribution. The prediction of bioeffects mayalso be complicated by movement of the sub-ject in the field which changes the absorbedenergy dosage and may result in modulationof the field.

The effects of whole body irradiation maydiffer from partial body exposure. In addition,for either whole or partial body irradiation,smaller body parts could resonate if the fre-quency used was in resonance with that partof the body.Environment. –The humidity, temperature,and air circulation of the surrounding environ-ment will affect the ability of a heated biologi-cal entity to cool. Objects near the elec-tromagnetic field could also enhance, reflect,absorb or distort it. For SPS, the effects of thespace environment on the biological responseto microwaves are not known.

SPS-Related Microwave BioeffectsExperiments (conducted by DOE, EPA)

In conjunction with the SPS DOE assessment,three studies were initiated and managed by EPA.46

• Exposure of bees to 2.45 GHz at 3, 6, 9, 25 and

●

●

50-mW/cm 2. No statistically significant effectson behavior, development, or navigation havebeen observed following short-term exposure.Long-term exposures are planned and shouldclarify this possible effect. It has also beenproposed that tests of effects on bee naviga-tion be carried out in the absence of sunlight(which may possibly mask microwave inducedeffects).Immunology and hematology studies of smallmammals exposed for short durations to about20 mW/cm2, 2.45 GHz microwaves. No effectshave been reported so far.Experiments testing the effects on the behav-ioral and navigational capability of birds sub-jected to acute and chronic exposures of 2.45GHz fields. Some mortality has resulted fromexposure to 130 to 160 mW/cm2 microwavesand has suggested that species and body ge-ometry determine tolerance levels. Generally,no statistically significant effects have beendetected at power densities of 0.1 to 2 5mW/cm2. Some birds chronically exposed to25 mW/cm2 have exhibited an increase of ag-gressive behavior, although the number ofbirds is statistically insignificant.

Laser Bioeffects

Lasers are unique among light sources becauseof their capacity to deliver an enormous amount ofenergy to a very small area at a great distance.47

The primary biological consequence of this proper-ty is heating. However, nonthermal mechanisms

‘“C H Dodge, Rapporteur, Workshop on Mechanisms Underlying Ef-fects of Long-Term, Low-Level, 2450 MHz Radlatlon on People, organizedby the National Research Council Committee on Satelllte Power Systems,Environmental Studies Board, National Academy of Sciences, ] uly 15-17,1980

4 ‘E- Kle IrI ‘ Hazards of the Laser,” Hosplta/ Practice, May 1967, pp48-5 J


have also been suggested.48 For example, photo-chemical reactions are thought to be responsiblefor damage of biological organisms exposed toultraviolet lasers.49 High laser power densities mayalso cause injury from shockwaves or high electricfield gradients.50 Biological electromagnetic in-terference effects have also been proposed.51

Clearly, the mechanisms of interaction betweenlaser light and biological entities are not complete-ly understood. Like microwaves, little is knownabout the cumulative or delayed effects of chronicexposure to low levels of laser light.52 In general,the higher the power and the shorter the period, thegreater the damage.53 The extent of the effect alsodepends markedly on the characteristics of the ir-radiated biological material. Of primary impor-tance is a tissue’s absorptivity, reflectivity, watercontent, and thermal conductivity.

The organ of the body most sensitive to laserradiation is the eye. The ocular media of the humaneye transmit light with wavelengths between 400and 1,400 nm. 54 There are two transmission peaks inthe near infrared at 1,100 and 1,300 nm. Light in thevisible and near infrared spectrum is focusedtowards the retina. The refraction of the laser beamby the ocular media amplifies the light intensity byseveral orders of magnitude.55 As a result, in thisspectral region the retina can be damaged at radia-tion levels which are far less than those which pro-duce corneal or skin damage.

For lasers that emit wavelengths outside of thevisible and near infrared range, the ocular effectsare quite different. At ultraviolet wavelengths, forexample, light is absorbed primarily by the cornea,which can be injured by photochemical reactions.Infrared radiation is not focused on the retina

‘“V T Tomberg, “Non-Thermal Blologlcal Effects of Laser Beams, ”Nature, VOI 204, Nov 28, 1964, pp 868-870

“Department of the Alr Force, Ffea/th ~azdrd~ Contro/ for Laser Radla-tlon, AFOSH Standard 161-10, May 30, 1980

‘[)lbld‘‘M Zaret, “Laser Appl Icatlon In the F Ield of Medlclne, ” ZAMP, VOI 16,

1965, pp 178-79“M L Wolbarsht and D H Sllney, ‘ N e e d e d M o r e D a t a o n Eye

Damage, ” Laser Focus, December 1974, pp 11-13‘‘Supra note 47“W T Ham, et al , “The Eye Problem In Laser Safety, ” Arch En-

v/ronmenta/ Hea/th, VOI 20, February 1970, pp 1 ;6-160“D H Sllney and B C Fresler, “Evaluation of Optical Radlatlon

Hazards, ” App/ied Opt/es, VOI 12, No 1, j anuar~ 1973, pp 1-24

either, but is absorbed by the cornea and lens. Mostof the radiation from the C02 laser is absorbed inthe 7 nm tear layer of the cornea. 56 Continuous irra-diances of the order of 10 W/cm2 could produce le-sions within the blink refIex.57 Corneal damage maybe reversible or repairable but severe damage mayresult in permanent scarring, blurred vision, andopacities. 58 The lens is particularly susceptible toinjury because of its inability to eliminate damagedcelIs. Lenticular damage characterized by cata-racts or clouding may occur at irradiance levelsthat do not produce corneal injury. For example,“glassblowers cataracts” are thought to result fromchronic exposure to 0.08 to 0.4 W/cm2 infraredradiation. 59 Proposed thermal limits for pulsed C02

lasers range from 0.2 to 1.0 W/cm2, ’0 but thisrecommendation requires further study.

Effects on the skin from absorbed radiation mayvary from mild erythema (sunburn) to blisteringand/or charring. 61 The principal mechanisms of in-jury by infrared radiation are thermal and are afunction of tissue reflectance, spectral depth ofpenetration, and the size of irradiated area. Sincethermal burns are produced at temperatures higherthan that which causes pain, in most present oc-cupational situations the pain can serve as warning.A definite sensation of warmth is produced fromC 02 lasers at 0.2 W/cm2 over an irradiated areaonly 1-cm diameter, or 0.01 W/cm2 for full body ex-posure. 62 Heat stress should not be overlooked.More research is needed to determine the effectsof chronic or repeated exposures.

As was the case for exposure to microwaves, thedetermination of laser thresholds and standards isexacerbated by problems of detection and meas-urement, instrument sensitivity, dosimetry, inter-species and interfrequency extrapolation, and lackof complete knowledge of physiological systems,mechanisms of interaction, and synergistic effects.

‘“U \ A r m y E n v i r o n m e n t a l Hyglence Agency, Laser and Opt/ca/Haiard~ Course Manua/, Aberdeen Proving Ground, Md , 8th ed , ]anuary1979

‘‘D H Sllney, K W Vorpahl, and D C Wlnburn, “ E n v i r o n m e n t a lHealth Hazards From High-Powered Infrared Laser Devices, ” Arch En-v/ronmenta/ Hea/tfr, VOI 30, April 1975, pp 174-179

‘“ Supra note 47‘9 Supra note 55““Suprd note 49“ Ibid‘2 Supra note 55


Experiments also make clear that the extent of thesuperficial or immediate lesion is no gage of totaldamage. ’3

The exposure limit for continuous wave infraredlasers as recommended by ANSI is 100 mW/cm2 forexposures over 10 seconds and for smalI spot sizeson the skin or eyes.64 A whole body irradiance limitof 10 mW/cm2 has been suggested .65 It should bestressed that the protection standards for repetitiveand chronic exposures and for wavelengths outsidethe visible band are based on a considerableamount of extrapolation. Data obtained from non-Iaser sources, such as bright, small-source lampsand high luminance extended sources cannot accu-rately and wholly represent the effects of laserradiation in determining injury thresholds forultraviolet and infrared lasers directly.

General Health and Safety ofSPS Space Workers*

The human body’s tolerance to accelerationdepends on the duration and magnitude of theacceleration, the positioning of the body relative tothe accelerating force, the restraint and supportsystems of the spacecraft and the time spent in aweightless state. ” Research is needed to quantifyeffects as a function of these parameters and todetermine the tradeoffs between short duration,high acceleration and longer duration, lower accel-eration effects. Studies should also evaluate thetolerance in the population that may fly in space(since variation in individual response levels aregreat) and explore possible ways to reduce harmfuleffects. ”

Weightlessness is known to induce a number ofphysiological responses such as decreased heartrate, shifting of fluids to the upper body, decreaseof muscle mass and loss of bone minerals .68 Mostof the observed effects have been temporary; onlybone calcium loss appears to require a long period

b* Supra note 47‘“American Natlona/ Standard for the Safe Use of Lasers, ANSI (R)

Z136 1-1979, American National Standard Institute“D H S1 Iney and D L Cono\,er, “Nonlonlzlng Radlatlon” In /rrdustr/a/

Errv/ronmenta/ Hea//h, L V Cralley and P R Atkins (eds ) (New YorkAcademic Press, 1975), pp 157-172

*See text for discussion of Ionlzlng radlatlon effects6bEnvironmen/a/ Assessment for the Sate///te Power ‘5 y$tern Concept L)e-

ve/opment and Eva/uatJon Program, DOE/E R-0069, August 1980“lbld“Program Assessment Report, Statement of F/nd/ng~, Satelllte Power

System Concept Development and Evaluation Program, DOE/E R-0085,November 1980

of recovery following return from space.69 For SPS,however, the effects of periodic weightlessnessover a long time period need to be investigated.Moreover, ameliorative measures suitable for alarge number of people with broad physiologicalcharacteristics must be investigated .’”

Workers would be exposed to electric fieldsgenerated by the collection and transmission oflarge amounts of electricity across the solar paneland antenna, but effects of electric and magneticfields on biological systems are not well-under-stood.71 Research is needed to determine the bio-effects of magnetic fields generated by satelliteelectric currents, as well as to assess the effects offield absence over extended stays in orbit, as CEOis largely outside of the Earth’s magnetic field.Some space workers could also be exposed to highlevels of microwaves. The effects of microwaves ina space environment deserves special attention. Itis known, for example, that microwaves can worksynergistically with ionizing radiation to increasethe biological effectiveness of the latter. ”Research would be required to determine bio-effects and if possible, to develop suitableexposure Iimits and protective clothing.

Psychological impacts must also be assessed,especially since there is little information on large,mixed gender groups working in close confinementfor prolonged periods. Studies should also considerthe effects on workers’ families and friends andpossible mitigation measures such as careful work-er selection, recreation faciIities, social manage-ment, etc.

Space workers could be prone to greater safetyrisks than their terrestrial counterparts because ofthe possible awkwardness of working without grav-ity.73 Risks also stem from the high-voltage equip-ment and handling of toxic materials. There is adanger that spacecraft charging could produceelectric shocks great enough to injure or killworkers, although this might be avoided by a ju-dicious choice of spacecraft material. CatastrophicCoIIisions with meteoroids or space debris are alsopossible, given SPS’s large size. Extravehicularactivity may also create hazards.

—‘}’lbld‘(’lbld7‘ Jupra note 66‘ Baranskl and P Czerskl, L310/oglca/ Effects of M/crowave~, Dowden,

Hut, hlnson and Ross, Pennsylvania, 19767 ‘\upra note 66

Appendix E

EXAMPLES OF INTERNATIONAL COOPERATION

Part 1

Intelsat was preceded by the formation of adomestic company, Comsat. In 1962 the FederalGovernment, after extensive debate over the prop-er degree of Federal involvement, chartered Com-sat Corp. to provide a commercial communicationssatellite system “in conjunction and cooperationwith other countries . . which wilI serve the com-munication needs of the United States and othercountries, and which wilI contribute to world peaceand understanding.’” Comsat was not directlyowned or run by the Government; it issued sharesof voting public stock (which were immediatelyover-subscribed), with 50 percent of these reservedfor “common carriers” —AT&T, ITT, WesternUnion, and others. The Board of Directors con-sisted of three Presidential appointees, six commoncarrier representatives, and six elected at large.However, although Comsat was not directly fi-nanced by the Government, it received and con-tinued to receive the benefit of extensive NASA-sponsored development of communication satel-lites and launch-vehicles, free of charge–someseveral billion dollars worth. (NASA research oncommunications satellites was cut back under theNixon administration but reemphasized in theCarter administration’s October 1978 White HouseFact Sheet, largely as a result of increased competi-tion from Japan and Western Europe.)

Under its charter, Comsat was allowed to enterdirectly into negotiations with foreign entities withthe supervision and assistance of the State Depart-ment. In 1963, a U.S. negotiating team proposed aframework for an international telecommunica-tions satellite organization: lntelsat. In a series ofmeetings details were agreed on: 1) that ComsatwouId be the consortium manager2 and majorityowner, with an initial 61 percent of the shares; 2)that ownership and utilization charges, as well asvoting, would be in proportion to the use of thesystem by each participant, readjusted on an an-nual basis, and that membership would be open toalI ITU member nations, with a minimum 15-per-cent share needed for representation and voting; 3)there would be two levels of agreement, one direct-

“’Communlcatlon> Satellite Act of 19b2, In Space Law, Se/ected Ela$fcDocuments, Senate Committee on (’ommerce, Science, and Transporttlon, Dec 1978, p 523

‘Joseph N P e l t o n , G/oba/ Comrnunlcatlons Sate//(te Po/Icy lnte/sat,Po/ItIcs and funct~onallsm (Mt Airy, Md Lomond Books, 1974), p 76(p 55)

Iy by nations, the other by designated agencies(“signatories”), one per nation; 4) that Intelsatwould be restricted to providing services betweencountries, not within countries; 5) the interimagreements would last 5 years, at which point per-manent arrangements wouId be agreed on.

One immediate result was the refusal of theSoviet Union and East Europe to participate. TheSoviets used only a miniscule amount of globalcommunications traffic, some 1 percent, andwould not join an organization dominated by theUnited States and West Europe. They began devel-oping their own domestic system (Molniya), whichlater formed the core of their international system,Intersputnik, covering the Soviet Union, EastEurope, Cuba, and Mongolia.

When the interim agreements were renegotiated,from 1969 to 1971, the basic structure was retained.However, a number of changes were made, manyof them designed to reduce U.S. dominance and toincrease the direct role of national governments.3

Comsat was phased-out as the manager, manage-ment being turned over to a Director General,responsible to a Board of Governors composed (in1979) of the 27 largest participants or groups of par-ticipants, representing a total of 83 signatories. Anew voting structure was established to prevent defacto U.S. veto power. The minimum participationwas lowered to 0.05 percent. AlI signatories andstates parties were entitled to receive free, tech-nical information generated by Intel sat contracts.Intel sat was allowed to provide services to domes-tic and regional satellite groups. Net property in1980 is valued at $663 mill ion, with $523 million ofthat in the space segment proper. Return on invest-ment in 1979 was better than 14 percent.4

Part 2

Like Intelsat, Inmarsat is a commercial, profit-making venture with a corporate structure and in-dependent legal personality. Comsat is the U.S. sig-natory, holding the largest original share at 17 per-cent; Great Britain is second with 12 percent, theSoviet Union third with 11 percent. ’ Initial cap-italization was set at $200 milIion.

Because it could participate on a more equitablebasis, the Soviet Union joined Inmarsat; one conse-

!R IC hard Col lno, The /rite/sat De flnlt/ve Arrangements (Geneva Euro-pean Broadcasting Union, 1973), p 11-12

‘Intel}at Annual Report 1980 Intelsat, Washington, D C , p 21“ Operating Agreement on Inmarsat,” 1976, In Space Law, p 445

289

290 Ž Solar power Satellites

quence was Soviet insistence that nongovernmen-tal signatories —e.g., Comsat and Japan’s KokusaiDenshin, Ltd.—be guaranteed by their govern-ments. It has been pointed out that the SovietUnion “is disinclined to enter mixed organizationsinvolving states and private enterprise, ” preferringto deal only with other states. G

Part 3

The vast majority of Intelsat signatories weregovernment communications agencies. Only in afew instances, such as Comsat for the UnitedStates, and Interspazio for Italy, were the signa-tories separate corporate entities designed for com-munication satellite operations. One result was aconflict of interest within agencies that were in-volved in other communication systems, especialIyunderwater cables. Differences of opinion also de-veloped between Comsat, which wanted to expandIntel sat into as many other areas, including domes-tic communications, as possible; and agencies thatwanted Intelsat’s scope restricted to internationaltelephone and television relay.

At the beginning, Comsat, with headquarters inWashington, D. C., was the managing agency; Amer-ican launchers were used through NASA; and thesatellites themselves were built by U.S. firms —(Hughes for Intelsat I, II, IV, and IV-A; TRW for ln-telsat III; Ford Aerospace for Intel sat V). The initialagreement was structured in such a way that U.S.participation could never be less than 50.6 per-cent. 7

Initially, participation by lesser developed coun-in numbers, tensions developed between LDCs,Europeans, and the United States over the distribu-tion of benefits. One issue concerned the relativeinvestment between satelIites and ground stations.Since users were responsible for building their ownEarth stations, LDCs and others with fewer re-sources and lower usage urged Intelsat to increasethe size and complexity of the satellite componentin order to reduce Earth-station costs.

As European aerospace capabilities matured,members began to lobby for larger shares of In-telsat R&D and procurement contracts. Even when

‘Stephen Doyle, “lnmarsat Origins and Structure, ” 1976‘Pelton, op cit , p 58

European bids were higher than U.S. ones, it wasargued that these were necessary to develop com-petition for the United States, and that it was unfairfor U.S. firms to reap all the financial benefits.Over time, U.S. firms began to subcontract exten-sively abroad in an effort to reduce criticism of U.S.contract dominance.

In the permanent agreement, procurement pol-icy was established with emphasis on the “bestcombination of quality, price and most favorabledelivery time.” However, in the event of equivalentbids “the contract shall be awarded so as to stim-ulate in the interests of Intelsat, worldwide com-petition” (art. 13).8 This loophole gave Intelsat theoption of allocating contracts on a geographicbasis as long as it determined that they wereroughly equivalent. In recent years, approximately15 percent of the dollar value of Intel sat procure-ment contracts has been spent outside the UnitedStates 9

Part 4

Unlike ESRO, which had its own facilities, ELDOwas entirely a coordinating body for separate na-tional efforts. The initial planning called for aBritish first stage, a French second stage, a Germanthird stage, and so on. Launches were to take placein Woomera, Australia. The major countries hadwidely differing interests. France was interested inan across-the-board capability to compete with thesuperpowers and demonstrate French independ-ence and prestige, an aim directly connected withFrench military programs in nuclear submarinesand intermediate range ballistic missiles. Francefeared that the United States would not providelaunch services for French military satellites or forprograms that promised to compete commerciallywith the United States.

Germany was more interested in private com-mercial ventures, and was much more willing tocooperate with the United States. Great Britain,faced by the mid-1960’s with severe financial con-straints and enjoying a close relationship with the United States, preferred less expensive programs intelecommunications and remote sensing.

““ Intel sat Organ lzatlon Agreement, ” 1973, In Space Law, p 214“Conversation with ]ohn Donahue, Intelsat procurement office, Oc-

tobel 1980

ACRONYMS, ABBREVIATIONS,AND GLOSSARY

Acronyms and Abbreviations

AF – audio frequencyAlAA – American Institute of Aeronautics and

AstronauticsANSI — American National Standards InstituteA-sat — antisatelliteAramco – Arabian-American Oil Co.BBB — blood brain barrierBRH – Bureau of Radiological HealthBtu — British thermal unitbui – brain uptake indexCB — citizens’ bandCEP – Citizen’s Energy Project

— centimeterCMEA — Council of Mutual Economic

Assistance (Comecon) (East Europe,Soviet Union, Cuba)

CNS – central nervous systemCONAES – Committee on Nuclear and

Alternative Energy Sources (NationalAcademy of Sciences)

COPUOS – Committee on Peaceful Uses of OuterSpace (United Nations)

COTV — cargo orbital transfer vehicleComsat – Communications Satellite Corp.cpmCWdBdcDODDOEDMSOEDLEEGEKGELDO

ELFEMFEMPEMREOTVEPAERESAESRO

FCCFDAFELCDLGNPGHzGw

— counts per minute— continuous wave– decibels– direct current— Department of Defense– Department of Energy– dimethyl sulfoxide— electric discharge laser— electroencephalogram m— electrocardiogram– European Space Vehicle Launcher

Development Organization— extremely low frequency— electromagnetic fields— electromagnetic pulse— electromagnetic radiation— electric orbital transfer vehicle— Environmental Protection Agency— evoked response– European Space Agency– European Space Research

Organization— Federal Communications Commission— Food and Drug Administration— free electron laser— gas discharge laser– Gross National Product– gigahertz (109 cycles per second)– gigawatt (109 watts)

GEOHEAO-C

HELHEW

HFHFALHLLVHRPHVTLHz

HZE

IAFICBMIEAIEEE

ISMITU

kgkmk wlaser

LEOLMFBRLORANMHzMPTSM WmW/cm 2

NASNASA

NATONBSNIEMRNIOSH

NRDCOECD

– geostationary orbit– High Energy Astronomical

Observatory-C– high-energy laser– Department of Health, Education and

Welfare– high frequency– high frequency auditory limit– heavy-lift launch vehicle– horseradish peroxidase– high-voltage” transmission line—

—

————

——

—

—

hertz: a unit of frequency equal toone cycle per secondhigh-atomic-number, high-energyparticlesInternational Astronautical Federationintercontinental ballistic missileInternational Energy AgencyInstitute of Electrical and ElectronicsEngineersindustrial, scientific, and medicalInternational TelecommunicationUnionkilogramkilometerkilowatt (103 watts)light amplification by stimulatedemission of radiation

– low-Earth orbit– liquid metal fast breeder reactor– long-range navigation– Megahertz (106 cycles per second)— microwave power transmission system— megawatt (10’ watts)— milliwatts per square centimeter— National Academy of Sciences– National Aeronautics and Space

Administration— North Atlantic Treaty Organization– National Bureau of Standards— nonionizing electromagnetic radiation– National Institute of Occupational

Safety and Health– Natural Resources Defense Council– Organization for Economic

Cooperation and Development(United States, Canada, Japan, WestEurope)

OMEGA — generic name for long-rangenavigation

OPEC – Organization of Petroleum ExportingCountries

293

294 • Solar Power SateLLites

OSHA

OTAPLVPOTVprfQQeR&Drem

RFP

– Occupational Safety and HealthAdministration

– Office of Technology Assessment– personnel launch vehicle– personnel orbital transfer vehicle— pulse repetition frequencies– Quad (quadrillion BTUS)– Quad, electric— research and development– Roentgen equivalent man, the

quantity of ionizing radiation whosebiological effect is equal to thatproduced by one roentgen of X-rays

— radiofrequency radiation

SAMSARSEPSSPSSRBCSSTOSTStTVAUHFVER

VHFW H O

— surface to air missile— specific absorption rate— solar electric propulsion system— solar power satellite— sheep red blood cells— single stage to orbit space vehicle— space transportation system— metric ton (tonne); 1,000 kg– Tennessee Valley Authority— ultra high frequency— visually evoked electrocortial

response— very high frequency— World Health Organization

Glossary

Ablate—to remove by cutting, erosion, melting,evaporation, or vaporization.

Aerosol—a suspension of insoluble particles in agas.

Albedo–the fraction of incident light or electro-magnetic radiation that is reflected by a surfaceor body.

Ambient—the natural condition of an environmen-tal factor.

Amplitude–the maximum departure of the valueof an alternating wave from the average value.

Artifact— a product of artificial character due to anextraneous agent.

Attenuation– a reduction in amplitude of electro-magnetic energy.

Beam width–the angular width of a beam of radia-tion, measured between the directions in whichthe power intensity is a specified fraction, usu-alIy one-half, of the maximum.

Bias current–the electric current applied to adevice (e.g., a transistor) to establish a referencelevel for operation.

Biota—the plants and animals of a region.Brayton cycle— a method of driving a turbine in

which a gas is compressed and heated. Themost familiar use is for aircraft gas turbineengines. An alternative to the Rankine cycle.

Bremsstrablung radiation– radiation from chargedparticles that are decelerated in a magneticfield.

British thermal unit-quantity of heat needed t o

raise one pound of water one degree Fahrenheitat or near 39.2 ‘F.

Circadian–pertaining to events that occur at ap-proximately 24-hr intervals, such as certain bio-logical rhythms.

Cloud condensation nuclei (CCN)–particles onwhich water vapor condenses to form waterdroplets, that in turn form clouds and fogs.

Convection-circulatory motion that occurs in theatmosphere due to nonuniformity in tempera-ture and density, and the action of gravity.

Cortical tissues–tissue from the outer layer of graymatter of the brain.

Cosmic ray–atomic nuclei of heterogeneous, ex-tremely penetrating character that enter theEarth’s atmosphere from outer space at speedsapproaching that of Iight.

Coupling–the mechanism by which electromag-netic energy is delivered to a system or device.

CW laser–continuous wave laser, as distinguishedfrom a pulsed laser. A laser emitting for a peri-od in excess of 0.25 second.

Cytogenetics– a branch of biology that studies

heredity and variation by the methods of bothcytology and genetics.

Cytology– a branch of biology dealing with thestructure, function, multiplication, pathology,and Iife history of cells.

Decible– a unit for expressing the ratio of twoamounts of electric or acoustic signal powerequal to 10 times the common logarithm of thisratio. A ratio of 10 is 10 dB, a ratio of 100 is 20dB, a ratio of 1,000 is 30 dB, etc.

Diffuse reflection— reflection of a beam incident ona surface over a wide range of angles.

Dosimeter– a device for measuring doses of radio-activity.

Ecliptic–the circle formed by the apparent yearlypath of the Sun through the heavens; inclinedby approximately 23.50 to the celestial equator.

Electromagnetic energy– energy in the entire rangeof wavelengths or frequencies of electromag-netic radiation extending from gamma rays tothe longest radio waves and including visiblelight.

Electron— a subatomic particle with a negativeelectrical charge.

Endocrinology– a science dealing with the endo-crine glands, which produce secretions that aredistributed in the body by way of the blood-stream.

Energy dose– the quantity of electromagneticenergy (in joules) that is imparted per unit ofmass to a biological body.

Energy dose rate— the amount of electromagneticenergy that is imparted per unit of mass and perunit of time to a biological body.

Epidemiology-a branch of medical science thatdeals with the incidence, distribution, and con-trol of disease in a population.

Extended source—an extended source of radiationthat can be resolved into a geometrical imagein contrast with a point source of radiation, thatcannot be resolved into a geometrical image; asource that subtends an angle greater than onearc min.

Exosphere–the outer fringe region of Earth’s at-mosphere.

Field intensity–the magnitude of the electric fieldin volts per meter or the magnitude of the mag-netic field in amperes per meter.

Flux–the rate of transfer of particles or energyacross a given surface.

Frequency—the number of complete oscillationsper second of an electromagnetic wave, meas-ured in hertz (Hz). One hertz equals one cycleper second.

295


Geostationary Earth orbit (GEO)– the equatorial or-bit at which a satellite takes 24 hr to circle theEarth so that it is stationary as viewed fromEarth; altitude approximately 36,000 km.

Geosynchronous Earth orbit–the orbit at which asatelIite takes 24 hr to circle Earth. (The satelIitemay or may not appear to be stationary above apoint on Earth.)

Harmonic frequency– a component frequency of anelectromagnetic wave that is a multiple of thefundamental frequency.

Heliostat– a mirror device arranged to follow theSun as it moves through the sky and to reflectthe Sun’s rays on a stationary collector.

Hematology-a branch of biology that deals withthe blood and blood-forming organs.

Heavy-lift launch vehicle (HLLV)– a proposed launchvehicle used to transport large masses of ma-terial from Earth to low- Earth orbit.

Illuminance– irradiance; rate of energy per solidangle measured at a given point.

Immunology— a science that deals with disease re-sistance and its causes.

Intermodulation –the mixing of the components ofa complex wave with each other in a nonlinearcircuit. The result is that waves are produced atfrequencies related to the sums and differencesof the frequencies of the components of theoriginal waves.

Intrabeam viewing– viewing the laser source fromwithin the beam. The beam may either be director specularly refIected.

Ion—an atom or group of atoms that carries apositive or negative electrical charge as a resultof having lost or gained one or more electrons.

Ionizing radiation– radiation capable of producingions by adding electrons to, or removing elec-trons from, an electrically neutral atom, groupof atoms, or molecule.

Ionosphere—the part of Earth’s atmosphere begin-ning at an altitude of about 5 km extending andoutward 500 km or more, containing free elec-trically charged particles by means of whichradio waves are reflected great distancesaround the Earth.

Irradiance (E)– radiant fIux density arriving at givensurface in units of watts-per-square-centimeter(W/cm2); illuminance (as measured by a detec-tor).

Joule (J)– unit of energy (1 watt-see) under the inter-national system. As a thermal unit, 1 jouleequals 0.239 calories. Since the calorie is de-fined as the energy required to heat 1 gram ofwater from 40 to 50 C, 4.184 joules is theequivalent of one calorie.

Kapton– Iightweight, tough plastic film.Klystron— an electron tube used to generate and

amplify microwave current.Laser– a device for generating coherent light radia-

tion.Low-Earth orbit (LEO) –altitude approximately 500

km.Luminance–brightness on a light source, equal to

luminous flux per unit solid angle emitted perunit area of the source.

Magnetron— a magneticalIy control led tube usedto generate and amplify microwave radiation;the power sources for microwave ovens.

Magnetosphere– a region of Earth’s outer atmos-phere in which electrically charged particlesare trapped and their behavior dominated byEarth’s magnetic field.

Mass driver– an apparatus for accelerating materialin an electromagnetic field.

Mesoscale–on or relating to a meteorological phe-nomenon approximately 1 to 100 km in horizon-tal extent.

Mesosphere– a layer of the atmosphere extendingfrom the top of the stratosphere to an altitudeof about 80 km.

Microwave– a comparatively short electromag-netic wave, especialIy one between 100 cm and1 cm in wavelength or, equivalently, between0.3 and 30 GHz ‘in frequency.

Modulation–when a continuous series of waves ofelectromagnetic energy is modified by pulsing,or by varying its amplitude, frequency, orphase, the waves are said, respectively, to bepulse-, amplitude-, frequency-, or phase-modu-lated. In order to convey information by radi-ating electromagnetic energy, it must be modu-lated,

Morphology-a branch of biology that deals withthe form and structure of animals and plants.

Multibiotic– having or consisting of many plantsand animals.

Multipath radiation— in contrast with a so-calledplane wave, that flows in a straight line throughspace, an area or volume where electromag-netic waves arrive from different directionsbecause of reflection or multiple sources is saidto be the site of multipath radiation.

Neuroendocrine-of, relating to, or being a hormo-nal substance that influences the activity ofnerves.

Neutral particles– molecules, atoms, or subatomicparticles that are not electrically charged.

Neutron–an uncharged elementary particle thathas a mass nearly equal to that of the proton

Glossary ● 2 9 7

and is present in all known atomic nuclei exceptthe hydrogen nucleus.

Noctilucent cloud— a luminous thin cloud seen atnight at a height of about 80 km.

Nonionizing radiation— radiation of too low an ener-gy to expel an electron from a molecule oratom.

Ohmic heating-a heating mechanism in a plasmaor other conducting medium. The free electronsin the medium are accelerated by an appliedelectric field and give up kinetic energy by col-lision with other particles.

Phase—the measure of the progression of a peri-odic wave in time or space from a chosen in-stant or position.

Phased array– an array of antennas that is aimed asa group by adjusting the phase of the signal itsends or receives.

Photoionization– ionization (as in the ionosphere)resulting from CoIIision of a molecule or atomwith a proton.

Photoklystron — a device for directly converting visi-ble light to microwave radiation.

Photon— a quantum of radiant energy.Photoperiod – the interval in a 24-hr period during

which a plant is exposed to Iight,Photovoltaic cell– a cell composed of materials

that generate electricity when exposed to light.Plasma–a collection of charged particles exhibit-

ing some properties of a gas but differing from agas by being a good conductor of electricityand by being affected by a magnetic field.

Polarization–the electric (E) and magnetic (H) fieldsthat comprise a propagating electromagneticwave may be fixed in relation to Earth’s hori-zon, or they may rotate. By convention, the vec-tor of the E field is related to Earth’s horizon: ifthe two are perpendicular, the wave is said tobe vertically polarized; if parallel, horizontallypolarized. When the E and H fields are continu-ously rotating with respect to the horizon, thewave is said to be elIipticalIy polarized.

Power–the quantity of energy per unit of time thatis generated, transferred, or dissipated. The unitof power, the watt (W), is defined as one jouleper second (j/s).

Power density-the quantity of electromagnetic en-ergy that flows through a given area per unit oftime. Formally, power density is specified inwatts per square meter (W/m2), but by traditionin biological effects studies it is usually ex-pressed in milliwatts per square centimeter(mW/cm 2).

Propagation —the transmission of electromagneticwave energy from one point to another.

Proton– an elementary particle that is identicalwith the nucleus of the hydrogen atom, thatalong with neutrons is a constituent of all otheratomic nuclei, that carries a positive charge nu-mericalIy equal to the charge of an electron.

Pulsed laser– a laser that delivers its energy in shortpulses, as distinct from a CW laser; a laserwhich emits for less than 0.25s.

Radiation pressure– all propagating electro-magnetic waves exert a very sIight pressure onan absorbing object.

Rankine cycle– a Iiquid gas cycle used often forsteam turbines. A working fluid is heated until itexpands and drives a turbine.

Rectenna– a coined term for the SPS reference sys-tem receiving antenna that also converts themicrowave power to direct-current electricity.

Rectification-the conversion of an alternating cur-rent to direct current.

Refraction– a deflection from a straight path under-gone by a wave in passing obliquely from onemedium into another in which its velocity is dif-ferent.

Root-mean-square—for an alternating voltage, cur-rent, or field quantity: the square root of themean of the square of the quantity during acomplete cycle.

Scattered power– power that is reflected or dis-persed as the result of an obstruction in thepath of the primary power flow.

Side lobe— refers to power radiated from an anten-na in a direction other than the desired direc-tion of transmission.

Slipring–a metal ring to conduct current in or outof a rotating member of a machine.

Solar flare– an explosion on the Sun which gener-ates fast elementary particles.

Solar wind–a stream of particles generated by asolarfIare.

Solid-state amplifier– an amplifier whose operationdepends on a combination of electrical effectswithin solids, e.g., a transisterized amplifier forelectromagnetic waves.

Specific absorption rate (SAR)–the quantity of elec-tromagnetic energy that is absorbed by a bodyper unit of mass during each second of time; ex-pressed formally in watts per kilogram (W/kg);often, informally as milliwatts or watts pergram (m W/g or W/g). “Specific absorption rate”is being considered by the National Council onRadiation Protection and Measurements as the


official nomenclature for expressing the doserate of radio-frequency electromagnetic radia-tions. Synonymous with energy dose rate.

Specular or regular reflection– a mirror-like reflec-tion.

Spurious power or frequency–electromagnetic en-ergy produced at frequencies that are not easilyrelated to a specified operating frequency.

Stratosphere– an upper portion of the atmosphereabove approximately 10 km (depending on lati-tude, season, and weather) and in which tem-perature changes little with changing attitudeand clouds of water are rare.

Sun-synchronous orbit– a near polar orbit whichkeeps the satellite in full sunlight all the timewhile Earth rotates beneath it.

Susceptibility—the sensitivity of an electromagneticreceiver to undesired electromagnetic wavesthat may resuIt in interference.

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Symptomatology– a branch of medical science con-cerned with symptoms of diseases.

Teratology-the study of malformation or seriousdeviations from the normal development offetuses.

Thermosphere–the part of Earth’s atmosphere thatbegins about 80 km above Earth’s surface, ex-tends to outer space, and is characterized bysteadily increasing temperature with height.

Troposphere– the portion of the atmosphere belowthe stratosphere, which extends outward about15 km from Earth’s surface, and in which tem-perature generally decreases rapidly withaltitude.

Van Allen belt— a belt of intense ionizing radiationthat surrounds Earth in the outer atmosphere.

Wave guide– a device for transmitting and guidingradio-frequency waves

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