OSO-H Press Kit

8/8/2019 OSO-H Press Kit

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NEWS NATIONAL AERONAUTICS AND SPACE ADMIN!STRATION TEI5 WO 2-4155WASHINGTON,D.C. 20546 WO 3-6925RELEASE NO : 7 1- 163 FOR RELEASE: September 16, 1971RELESE N:11633 PM

PROJECT: OO-H

E contentsHGENERAL RELEASE -------------------------------------- 1-8THE STUDY OF THE SUN -------------------------------- 9-10SOLAR GLOSSARY --------------------------------------- 11-13THE SPACECRAFT AND ITS OPERATION --------------- --- 14


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IW U ANATIONAL AERONAUTICS AND SPACE ADMINISTRATION (202) 962-4155WASHINGTON,D.C. 20546 TELS: (202) 963-6925FOR RELEASE: September 16, 1971Joseph J. McRoberts 3 PM(Phone: 202/962-1176)

RELEASE NO: 71-163

OSO TO CONTINUE STUDY OF THE SUN

The most advanced and largest spacecraft in the OrbitingSolar Observatory (OSO) series is scheduled for launch by theNational Aeronautics and Space Administration aboard a Delta


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Bright streamers in the corona will be recorded up todistances of five million miles from Lhe surface of the Sun,and their evolution and rotation with the Sun will be studied.Active regions and their extent into the corona will beobserved by the X-ray experiment with the goal of understand-ing their role in heating up the corona to millions of degrees,and their relation to the streamers seen in white light.

During active periods the OSO-H will, obtain measurementsof X-ray and ultraviolet radiation from high temperatureplasma explosions on the Sun, called solar flares; the causeof these explosions and the method by which the plasma reaches


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-3-The 1,400-pound Observatory, twice the weight of any

previous OSO, will be launched aboard NASA's two-stage DeltaN launch vehicle into a circular Earth orbit. The Delta willalso carry a 45-pound secondary payload satellite -- NASA'sTest and Training Satellite-D (TETR-D). This satellitecarries instrumentation to simulate the Apollo signals.Launching it with OSO is an economical way to provide forthe evaluation and development of ground systems as well asto train personnel in NASA's Manned Space Flight Network.

The planned orbit for both spacecraft is circular, 345


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The Sun is the source of most energy for life on Earth.Only by viewing the Sun from above Earth's energy absorbingatmosphere, can scientists get a truly sharp view of this"nearby" star and learn more about its influence on Earth.In fact, knowledge gained from CSO satellites might aidphysicists searching for an unlimited and pollution-freepower source on Earth.

The extremely hot plasma in solar atmospheric phenomena isalso suspected as the site of nuclear fusion energy generation.The primary problem encountered in laboratory studies ofcontrolled nuclear fusion, in research to develop a virtually


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Variations in the Sun's output of energy can drasticallychange the ionosphere and cause geomagnetic storms. Theseupper atmospheric changes can wipe out shortwave radiocommunications on Earth for neriods up to several hours.

Solar energy impinging upon Earth's lower atmosphereand surface, cause the wind pressure circulation patternswhich move weather systems around the globe.

In addition to its importance to and influence on Earthand human life, the Sun provides man with his only oppor-tunity to study a star at close range. It is 30 trillionmiles closer to Earth than the next


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Solar flare observations thus far have, in fact, taughtscientists more about plasma physics that can be applied,in general, than about the mysteries of what constitutesa solar flare. The OSO-H's solar flare studies may welladd to this basic storehouse of knowledge.

The OSO-H is similar in appearance to the six previousOSO's launched into Earth orbit. However, advanced solarscanning control and attitude sensing instruments have beenadded to the spacecraft in support of the more sensitiveexperiments assigned to this mission. The Observatory con-sists of two connected sections: an upper sail-like structure


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-7-A new gyroscope, added to the sail section on OSO-H,

retains a memory of the Sun's position so that the instru-ments can lock on the Sun much more rapidly after the satelliteemerges from the Earth's shadow.

On previous OSO's, the sail section would stop pointingin the direction of the Sun and start spinning with the wheelsection on entering Earth's shadow.

The six experiments carried by OSO'H weigh a total of497 pounds. They are provided by the Goddard Space FlightCenter, the Naval Research Laboratory, the MassachusettsInstitute


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This and the preceding OSO's were designed, built, andtested by Ball Brothers Research Corp., Boulder, Colo. TheDelta launch vehicle is built by McDonnell Douglas AstronauticsCo., Huntington Beach, Calif.

The TETR program is directed by NASA's Natwork Developmentof Engineering Support Implementation Division, Office ofTracking and Data Acquisition. Project management is underthe Goddars Space Flight Center, Greenbelt, Md. The TETRspacecraft are designed and built by TRW's Space VehiclesDivision, Redondo Beach, Calif.


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THE STUDY OF THE SUN

The source of almost all energy in the solar system,the Sun, is a hot ball of gases 864,000 miles in diameterpowered by nuclear reactions ir its deep interior. Solarflares often erupt in the chromosphere (a thin zone abovethe visible surface) and can produce X-rays, ultravioletradiation, and high energy particles that can strike theEarth. The outermost portion of the Sun, its corona, con-stantly sheds material known as the "solar wind" whichstreams out into space.

As solar energy impinges upon the Earth, its lethalultraviolet and X-rays are absorbed in portions of theatmosphere, while the visible "white light" strikes and warmsthe lower atmosphere, land and the seas.Although our atmosphere thus protects us fiom much ofthe lethal energy, it also restricts the terrestrial obser-


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The other principal task of the OSO-H is to study theX-rays and extreme ultraviolet radiation from solar flaresand "active regions" in the solar corona. Such studies willhelp the OSO scientists better understand the cause of flares,what happens in a flare, and how it affects us on Earth.Along with making solar measurements, the OSO-H alsowill measure the position, intensity, and energy range ofX-ray sources in the Milky Way Galaxy and possibly beyond.As is the case most often with all basic research, thebiggest "payoffs" in the study of the Sun have been unsus-pected. Studies of solar flares, for example, have so fartaught us much about plasma physics that can be applied ingeneral, although we have yet to solve the mystery of whatcauses a flare.Helium, which has many important industrial uses, wasdiscovered on the Sun by earlier solar scientists before itwas found on Earth. The unique conditions of temperature


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SOLAR GLOSSARY

Age: Estimated 5 billion yearsDiameter: About 864,000 miles (109 times thatof Earth)Volume: 1,300,000 times that of EarthMass: 333-000 times that of EarthSurface Temperature: 10,000 F (Earth, average of 32 F)Interior Temperature: 22 to g7 million degrees F. (Earth,

5000Rotation

(as seen from Earth): Varies, more rapid near the equator


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Cosmic Ray Particles: Mostly protons with energies rangingfrom less than 10 MeV (million elec-tron volts) to 50 BeV (billion elec-tron volts).Gamma Ray: A quantum of electromagnetic radiationemitted by a nucleus as a result ofof a transition between two energylevels of the nucleus. Energiesrange from 100,000 to 1,000,000 elec-tron volts, perhaps greater.Granulations: Irregular in shape, they appear overthe entire surface of the Sun ex-cept in sunspots. Constantly inmotion, they have a turbulent life ofonly a few minutes.Limb: The edge of the Sun's disk, as seenfrom Earth.


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Sunspots: The dark areas in the photosphere havingextremely strong magnetic fields. Someof the larger ones have a total areaof several million square miles. Thetemperature within a sunspot is be-lieved to be several thousand degreesless than that at the photosphere.The number of sunspots varies over asolar cycle of 11.3 years betweenmaxima sunspot activity. Seen in thelight of calcium atoms, the sunspotsare surrounded by larger bright re-gions called plages.

Umbra: The dark central portion of a sunspot.The same term is used to describe thedark central part of the Moon's shad-ow during an eclipse of the Sun.

Flares: Short-lived brightenings in a plage


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OSO-H SPACECRAFT AND ITS OPERATION

The OSO-H is an improved version of Lhe original OrbitingSolar Observatory concept. At 1,400 pounds, it weighs morethan twice as much as any previous OSC. The additional weightis required by the necessary advanced support systems for thehighly sensitive experiments assigned to the mission.Structural design concept of the OSO-H is basically likethe six OSO's already launched into Earth orbit for a continuingstudy of the Sun. It consists of two connected sections: anupper sail-like structure which carries the two primary experi-ments to be pointed at the Sun; and a lower rotating wheelsection which carries the basic Observatory support instrumen-

tation and four experiments. The three momentum arms on previousOSO's have been eliminated by putting more balance weights intothe wheel structure.Rotation of


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X Y & (CxoverAeWdith SowaeC Arrays)( m dintodxpw-mmnt)

WLtwkvioat Coronagraphs

Rotating Wherl Section(Carrie 4 E.tpeimernts)

(Coo4 *-nmmRestr Readout System

Pointod ExperimentsControl Systamr

Artiftcal Solar EclipseDevice

ORBITING SOLAR OBSERVATORY-H


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THE OSO-H EXPERIMENTSPointed Experiments

Dr. W. M. Neupert, NASA Goddard Space Fliqht Center --X-RAY AND EXTREME ULTRAVIOLET S T E GRAHThis 74-pound experiment is designed to deduce the distri-bution of matter and temperature in the Sun's corona aboveactive regions and determine how these quantities change inthe corona during solar flares. Further, it will generatespectroheliograms of th-a Sun in selected spectral lines between1.75 Angstroms and 400 Angstroms wavelength, and obtain spectraof selected areas of the solar disk.As a secondary objective, this experiment will attempt todetect polarization of the X-rays from active regions. Polari-zation is a property of light which carries information aboutthe conditions under which it was produced.

Dr. R. Tousey, Naval Research Laboratory --- WHITE LIGHT


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Dr. E. L. Chupp, University of New Hampshire -- SOLAR GAM1MARAY M.ONITOFThe purpose of this 74-pound experiment is to detectand measure the gamma ray fluxes in the energy range from0.3 to 9.1 MeV (millions of electron volts) during solarflares. Provision for detecting bursts of high energysolar neutrons is also included. It can thus detect nuclear

reactions in flares and elsewhere on the Sun.

Dr. L. E. Peterson, University of California -- HIGH ENERGYCOSMIC X-RAY EXPERIMENTThis 93-pound experiment is intended to observe theintensity, position, and spectrum of cosmic X-ray sourcesin the 10 to 5U0 keV range.

Dr. L. E. Peterson, University of California -- HARD SOLARX-RAY MONITOR


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TEST AND TRAiNING SATELLITE-D

The objectives of the Test and Training Satellite (TETR)project are to develop, launch and operate a series of spc.ce-craft for evaluation and development of ground systems aswell as train personnel in NASA's Manned Space Flight Network(MSFN).The TETR-D, fourth spacecraft in this series, carries anS-Band transponder which receives and transmits signalssimulating those of the Apollo spacecraft.Designated TETR-4 in orbit, the 45-pound spacecraft ismounted in the rear section of the Delta Launch Vehicle secondstage. It will be ejected rearward at two feet per secondabout 18 minutes after the OSO-H is separated from the launchvehicle.The launch plan calls for placing the TETR-D into a cir-cular orbit about 345 statute miles above Earth. Inclinationof the orbit to the equator is 33 degrees, and the orbital


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106 IFairing

OSO -81

fl.rcod StageDaee:47 feetIBurning Time. 375 seconds first burnI 6.6 seconds second bu~nAeae Thrust: 7,700 poundsWiht: 7 tons

65TETR-D location

First StageDiameter: 8 feet- Burning Time: 218.5 secondsAverage Thrust: 170,000 poundsWeight: 93 tons


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LAUNCH AND ORBIT SEQUENCE OF EVENTS

The sequence of events from liftoff until the spacecraftis fully operational is as follows:Launch Sequence

Event Time (Seconds)Liftoff 0 00Solid Motors Burnout 38Jettison Solid Motor Casings 75Stage I Burnout 218Stage II Ignition/Stage I Separation 223Jettison Fairing/Start OSO Sail Spinup 231Stage Ii Cutoff 597Coast Pitch Maneuver 636-837Restart Stage II


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Orbit Sequence

While in orbit, the Observatory spin axis is maintainednormal to the Sun vector within 4 degrees. This is accom-plished by an automatic pitch control system using gas jetsand a manual control system using a magnetic pitch coil. Whenactivated, the gas jets precess the spacecraft, thus pro-viding a coarse control about the pitch axis. This automaticpitch control system can also be operated manually by commandcontrol.No experiment high voltage will be turned on for approxi-mately three days. This period will permit sufficient timefor outgassing from the Observatory. It will also providetime to evaluate the basic operational subsystems and lowvoltage circuits of the Observatory prior to initial experi-mentation.About 72 hou- after launch the GSFC OSO control centerthrough the Fort Iv_ rrs, Fla.; Johannesburg, Republic of SouthAfrica; and Orroral.. Australia, Tracking and Command Stationswill initiate comrx.' s to turn on then turn off the first wheel


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OPERATIONS CONTROL, TRACKING AND DATA ACQUISITION

The 0SO-11 mission will be controlled from the OSO ControlCenter at the Goddard Space Flight Center.Tracking, acquiring data, and generating commands tothe Observatory will be accomplished by NASA's Space Trackingand Data Acquisition Network (STADAN). Communications betweenthe OSO Control Center and the STADAN stations flow two-wayover the NASA Communications System -- NASCOM. Both STADANand NASCOM are managed by Goddard.As the OSO-H orbits the globe once about every 96 minutes,it continuously transmits spacecraft and experiment data backto Earth, and simultaneously records the data on one of twoonboard tape recorders. Since the OSO is not always in sightof a ground station, this data may be played back later, uponground command, at 18 times recorded speed.The primary STADAN station for generating commands tothe OSO-H1 and acquiring data from it is located at Fort Myers,Fla. Other stations with a command capability located in


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750 D750

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75" 75SPACE TRACKING & DATA ACQUISITION NETWORK

85"0011600 140 1200 two0 80 600 400 20 00 20 400 60 80 1000 120 1400 160 5


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THE PROJECT, EXPERIMENT AND LAUNCH TEAM

NASA Headquarters, Washington, D.C.(Program Direction)Dr. John E. Naugle Associate Administrator for

Space Science & ApplicationsJesse L. Mitchell Director of Physics and AstronomyProgramsC. Dixon Ashworth OSO Program ManagerDr. Goetz K. Oertel OSO Program ScientistMichael E. McDonald OSO Program EngineerJoseph B. Mahon Director, Launch Vehicles

and Propulsion ProgramsI. T. Gillam, IV Delta Program ManagerGerald M. Truszynski Associate Administrator for

Tracking & Data Acquisition


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Kennedy Space Center, Cape Kennedy, Fla.(Launch Operations)Dr. Kurt Debus DirectorJohn Neilon Director, Unmanned Launch OperationsHugh A. Weston Manager, Delta Operations

Ball Brothers Research Corporation, Boulder, Colo.(Spacecraft Development)0. E. Bartoe PresidentJohn 0. Simpson OSO Program Director

McDonnell-Douglas Astronautics Company, Huntington Beach, Calif.(Launch Vehicle Production)Marcus F. Cooper Direczor, Florida Test Center,Cape Kennedy


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CONTRACTOR NAME STATE POLE OF CONTRACTOR AMOUNT(IN R$)

Spacecraft:Ball Brothers Research Corporation Colorado Prime Spacecraft Con- 11,787(Peak employment of 165 people in tractorOctober, 1970)

Major Sulcontractors:Parsons California Supplier of StructuralHoneycomb 288Spectrolab California Supplier of Solar Panels 93Bendix New Jersey Supplier of Flight Gyro 286EMR Florida Supplier of PCM System 97AVCO Ohio Supplier of Command System 608

Experiments:Ultra Violet Experiment - NRL Wash. D.C. Experimenter 1,893

Major Subcontractors:Bendix New Jersey Supplier of XlV Instru-ment 757EMR Florida Supplier of Coronograph 1,17 8EUV Spectroheligraph Experiment - GSFC Maryland Experimenter 314Major Contractor:General Electric Pennsylvania Designed & Fabricated 4,019InstrumentCosmic Ray Experiment - MIT Massachusetts Experimenter - Designed 1,584& Fabricated InstrumentGamma Rav Exneriment - U. of New N. Hampshire Experimenter 569Hampshire

Major Subcontractor:Time Zero, Inc. California Fabricated Gamma Ray Monitor 1,655

NOTE: Data are through launch -- does not include post-launch data analysis.- more -


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CONTRACTOR NAME STATE ROLE OF CONTRACTOR AMOUNT(IN K$)

Cosmic Ray Experiment - U. of Calif. California Experimenter 876Major Subcontractor:

Ball Brothers Research Corporation Colorado Fabricate Electronics 663Solar X-Ray Monitor - U. of Calif. California Experimenter 400Major Subcontractor:

Analog Technology Corporation California Design & Fabricate Monitor 1,332

NOTE: Data are through launch -- does not include post-launch data analysis.

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