DOCUMENT RESUME

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AUTHOR Steenblik, Jan W., rd.TTTLE Air & Space, Vclume 3, Number 5, May-June 1980.INSTITUTION Smithson4an Inst4tution, Washington, D.C. National

Air And Space,Museum.PUB CATE 80NOT? 17v.: Photographs may rot reproduce well.

EDES PPICFDEBCPIPTORS

IDENTIEIEPS

MF01/PC01 Plus Postage.*Aerospace Education: Aerospace Industry; *AircraftPilots; Aviation Technology: *Flementary SecondaryEducation: Engineering: *Museums; Physical Sciences:Science Activities; Science Education; Scientificresearch: *Space Exploration: Space SciencesParachutes

ABSTRACTThis issue is devoted to parachutes throughout man's

involvement in flight. Student activities are described in which theconstructicn of parachutes is encouraged. Women parachutists arehighlighted. ISA)

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U S DEPARTMENT OF WEALTH,EDUCATION I WELFARENATIONAL INSTITUTE OF

EDUCATION

THIS DOCUMENT HAS BEEN REPRO.DuCED ExAC 'Ls, AS RE-ElyED F ROMTHE PERSON OR ORGANIZAT ION ORIGIN-ATING IT POINTS OF VIEW OR OPINIONSSTATED DO NOT NECESSARILY REPRE-SENT OFFICIAL NATIONAL INSTITUTE oFEDUCATION POSITION OR POLICY

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Vol. 3, No. 5 May-June 1980

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P A R A CHUTESn December 19, 1972, astronauts Eugene A. Cer-nan, Ronald E. Evans, and Harrison H. Schmitt

came hurtling back to Earth in the Apollo 17 CommandModule. They had traveled 800,000 kilometers (500,000miles) through the emptiness of space, had walked anddriven upon the Moon. Whether their lunar landingmission would end in triumph or tragedy now dependedon three tightly packed bundles of cloththe CommandModule's parachutes.

All three Apollo 17 paracItutes worked as designed(above left), and the astronauts splashed down safely inthe Pacific Ocean.

The parachuteoriginally conceived for descentscenturies before successful human flighthas been de-veloped into a highly reliable mechanical device inrecent decades. Like the crew of Apollo 17, all previous

U.S. astronauts and test animals that rode winglessrockets into space returned safely to Earth by parachute.

Today, thowiands of skydivers in pursuit of sport andrecreation stake their lives on the high reliability ofmodern parachute equipment. Above right, a competitorat the 1976 U.S. Parachuting Championships stomps a10-centimeter (4-inch) disc in accuracy. competition.

Tne jumper's double-surfaced "ram-air" or "square"parachute canopy creates aerodynamic lift like an air-plane wing. The canopy scoops air with its open leadingedge to pressurize and maintain its airfoil shape. Thatshape makes possible highly maneuverable flightspeedsup to 32-48 kilometers (20-30 miles) per hour, glidingmore than 3 meters forward for every meter of descent,and braking to stand-up landings on one foot. More onparachutes, page 4.

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SCANFor brevity, the National Alr and SpaceMuseum Is often referred to In thesepages as NASM. The National Aeronau-tics and Space Administration is NASA.

Air & Space, a mini-magazine foreducators, is published every othermonth, September through May, asan outreach of the National Air andSpace Museum, Smithsonian Insti-tution, Washington, DC.

Air & Space combines informa-tion from many sources for a con-densed overview of the history, sci-ence, technology, and social lm-pact of selected aviation and spacesubjects.

MUSEUM HOURSUntil Labor 1Day (September 1), theMuseum NeW1 be open from 10 a.m. to9 p.m.; starting September 2, Museumhours will be 10 a.m. to 5:30 p.m. TheMuseum is open to the public everyday of the.year except Christmas.

SPECIAL PRESENTATIONSCALENDAR

The NASM Special Presentations Cal-endar is issued quarterly and is avail-able without charge to the generalpublic. To be put on the mailing list,send your name and address to Quar-terly Calendar, Presentations Division,National Air and Space Museum,Washington, DC 20560.

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In view of financial limitations,Air & Space is not accepting anynew registrations at this time.

Back issues of Air & Space areavailable on microfiche throughUniv6rsity Microfilms Interna-tional, Inc., 300 N. Zeeb Road,Ann Arbor, MI 48106.

BriefingNoel W. HinnersDirector, NASM

One of the earliest fears detectable in babies is that of falling. As wegrow up, we try to protect ourselves against the dangers of falling,either by avoiding situations that threaten to make us fall, or byeasing the effect of a fall. Having acComplished that, we then seem ,toget a special thril out of testing ourselves against those fears, even tnt,the point at times of flirting with death. Since most of us have noparticular desire to exceed the bounds of survivalit is exceedinglymore pleasant to-äpproach the limit and survive in sufficient health tobrag about the accomplishmentwe frequently call on mechanicalaids to give us a desirable margin of safety. Thus some 500 years agodid an "engineer" design the first known "guard", against a "fall"(possibly the fall awaiting those who leaped in desperation from burn-ing buildings). If you were a linguist of the day, you could combinethe equivalent Latin parare (to guard against) with the French chute(a fall) and coin the word parachute. -

Today, the parachutethe theme of this issue of Air & Spaceserves not only to rescue people from aerial^emergencies (as it has forover 200,000 persons to date). It also enables aerial adventurers toexperience the thrill of extended freefall (skydiving), live to tell aboutit, and do it again!

We've come a long way in the past seven decades in the use ofparachutes. Used sparingly in World War I, they were greatly'improvedduring the 1920s and '30s. Parachutes were used extensively in WorldWar II for both escape from damaged airplanes and the rapid deliveryof men and supplies to the battlefield. During the postwar period,with the advent of high-speed aircraft, the parachute became indis-pensable for both slowing them down during landing and aiding theirrecovery from spins.

A relatively new use,, of the parachute during the past 20 years hasbeen in the space program, most obviously in aiding the safe descentof the U.S. and Soviet manned spacecraft returning from Earth orbit. Infact, without parachutes, many of the space missions might not havebeen possible, because building shock-absorbing material into thespacecraft for landing would have added more weight than was allow-able. In space science programs, the parachute has served an equallyimportant function, that of slowing down planetary probes to enablesoft landings (on Mars by the Viking Lander) or to give them enoughtime to measure the structure and composition 'of the planet understudy (Pioneer Venus and the Jupiter probe on the Galileo mission).

Finally, as ycu read this issue of Air & Space, don't 'forget to look atthe parachute as a work of art. There are few sights prettier than a big,billowing conical parachute descending, or the graceful, controlledglides of the bright multi-colored rectangular and triangular sportcanopies that skydivers fly to tiptoe touchdowns within ce timetersof a preselected target.

2 Air & space, May-June 1 0

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Above: This parachute design, probablythe world's first, is from a sketchbookof the late 1470s or early 1480s by anunnamed engineer from Sienna, Italy.

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PARACHUhave been letting th precious cargoesdowngently f r mo than 180 years

by C. G. SweetIngCurator of FlIght Materiel

Department of Aeronautics, NASM

Although the exact origin of theparachute is not known, the basic

«incept goes bac k several centuries.The parasol, in use in Assyria 2800 yearsago, is believed to have been the in-spiration for the parachwe because ofthe resistance it offered to the wind.Lady legends in China and elsewheremention experiments with umbrellasand similar devices. What may havebeen ihe world's fiNt actual parachutedesign was a conical contralition drawnlw an unnamed engineerprobablyfrom Sienna, Italy---in the late 1470s orearly 1480s. Leonardo da Vinci sketcheda p\ ramid-shaped parachute in 14 95and described its proposed use: escapefrom tall burning buildings. Hungarianbishop f austus Verantius published anillustration of a parachute squarewooden framework covered \sith fabric

-in his book New Mac hines, printedin 1(, 15-16. There is no proof that anyol !nese designs %sere ever tested.

With the invention of the balloon inthe cyrIv 1780s (see "The Irwention ofLighter-than-Air Craft," May-lune '1979Air ,i)acei, the Para( hute found apractical applic anon. I xlubition para-huung spread ac ross Lurope despite

the unstahle nature of early parachutecanopies.

Andreda«jues Garnerin, a French-man, is c redited with making the firstparac huto descent from a balloon on

Above: André-Jacques Garnerin made the first parachute descent from a balloon thathe released over Paris on October 22, 1797. Right: Attack by enemy airplanes motivatedWorld War I aerial observers to leap from their tethered balloons. Note the parachutesuspension lines pulling the parachute canopy from the container attached to theballoon's rigging. Below: The U.S. Army Type A parachute intmduced in 1919 was oneof the first that could be worn on the body. Wearing the black hat is Leslie L. "Sky-HI"Irvin, parachute inventor, jumper, and manufacturer.

October 22, 1797, from a height ofabout 640 meters (2100 feet) aboveParis. Garnerin rode in a wicker baskethung from his umbrella-shaped para-chute. Louis Charlies Guille made thefirst parachute descent in the NewWorld in 1819 when he cut away froma balloon flying 152 meters (499 feet)over Jersey City, N.J. Many thrilling ex-hibition descents were made from bal-loons during the 1800s, but the typicalparachute was still a bulky, inefficient,stiff-ribbed umbrella that was imprac-tical as an emergency lifesaving device.

The Parachute and the AirplaneFew early airplane pilots used para-chutes. Despite many engine and struc-tural failures, most of the pioneer avia-tors preferred to take their chanceswith the disabled aircraft. Many pilotsconsidered parachutes to be unreliableor suitable only for exhibition drops.

To be practical for use with an air-plane, a parachute had to be relativelylightweight, compact, strong and, pref-erably, opened by the jumper after hecleared the aircraft. (Many early para-chutes were opened by a stotic line, a

strong cord connecting the parachutepack with the airplane. The static lineopened the pack as the juniper fellaway from the aircraft.)

Charles Broadwick, a balloonist andjumper, developed a compact para-chute that he wore on his body andused hundreds of times for exhibitions.Leo Stevens-,.also developed a para-

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Above: StrOking Intd the turbulent upper layers df Jupiter's primitive atmospherd, theGalileo Probe will simultaneously deploy its main parachute and jettison the heat shieldthat will protect the descent module during atmospheric entry. NASA-sponsored tProjectGalileo will bo a two-part unmanned scientific mission to our Solar System'so, largeitplanet: the Probe will study the Jovian atmosphere, while the Orbiter will make Nitrifiedobservations of Jupiter, its satellites, and magnetosphere.

More than 375 years after GalileoGalilei looked through his tele-

scope in 1610 and discovered Jupiter's.four largest satellites (moons), ProjectGalileo--sponsored by NASAwill or-bit a spacecraft around lupiter andsend a probe deep into that planet'sat mosphere.

The 'purpose of the Galileo missionis to smk important information aboutthe origin pnd evolution of the. SolarSystem. Jupiter's primitive atmosphereis believed to be a sample of the orig-inal material from which stars arefornwd, still unmodified by nuclearprocesses. Therefore, scientists are con-fident that the Jovian -system--Jupiterand its satellites will rrevea I importantnew insights into large-st ale phenom-ena thin relate to our understanding ofall of the Sun's planets, including Earth.

Project Galileo is designed to- pro-.vide an in-depth study of Jupiter, . itsfour largest (Galilean; satellites, and itsma,tnetosphere (the space around Jupi-ter occupied by its strong fnagneticfield). To conduct all these observa-tions, two kinds of spacecraft are re-quired: a probe and an oibitpr.

The suc cessfut Voyager missions tolupiter and its satellite; in 1979 pro-vided planetary s ( 'enlists with a wealthof new information about this «)mpli-cated systent. The. Voyager results em-

,,phasi/ed the need for the uniquecapahilities that a probe and an orbiter

could bring together to lovian scientificinvestiga turns.

Voyager returned fascinating pic-tures of the motions of the c louds fllupuer's atmosphere; however, thedata suggest that the sour( es of thesecomplex meteorological movements lie

Air & Space, May-lune 1980

deep within the atmosphere. The Gali-leo Probe will extend 'our knowledgein' depth, makipg direct measurementsof the composition, energjt. Ealance,and structure of Jupiter's atmoSphere.The Probe will penetrate at least 100kilometers (62 miles) beloW the visiblecloud layer before it loses contact withEarth. The Probe will reach a pres5ureof 10 to 20 Earth atmospheres.

Thc? Orbiter will extend our ;knowl-edge in time by following the notionsof Jovian clouds during the 20 er moremonths in which. it will return datafrom orbit abbut JuPiter: The Orbiter's.improved instrumentation and closesatellite flybys (10't 100 times closerthan those. of Voyage will allow muchmore detailed studies f the four di-verse Galilean satalles. Several en-tounters with each satellite wid givehigh-resolution information on thestructure and composition of differentareas of the surfaces. The multipleclose encounters also will permit prob-ing the gravity and the possible mag-netic fields of the satellites, thus pro-viding clues to their internal structures.

Voyager provided abundant evi-dence for many phenomena in theJovian system that change over time,phenomena that it found in 1979 to bechanged in many important respectssjnce Pioneer 10 and 11 flew by in 1973and 1974. The whole range of Orbiter

Right: Designed for a single launch in1982, the original Project Galileo conceptinvolved sending the Orbiter and Probe toJupiter as a unit. Nearing Jupiter, the twoinstrument packages would separate, as

:shown In this artist's rendering. NASA'srvised plAns call for two separatelaunches in 1984.

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investigationsboth remote sensing oftthe planet and its satellites, and directmeasurement of ionized particles andmagnetic fields in the magnetosphere-1-will be repuired to unravel some ofthe major Jovian mysteries. These in-clude the complex interactions amongvolcanic gases from lo (Jupiter's mostgeologically active satellite), the com-position and energy-balance of chargedparticles in the magnetOsphere, andthe state of Jupiter's upper atmosphereand aurorae.

Both Probe and Orbiter experimentswill allow scientists to follow up onVoyager's discoveries, such as lightningon Jupiter, .the planet's ring system,and the volcanic activity on lo.

The Project Galileo spacecraft wasdesigned to be carried to Low EarthOrbit by the Space Transportation Sys-tem (Shuttle Orbiter) and launched.after separation from the Shuttle. NASAoriginally planned to launch Galileo inearly 1982. The 1982 launch plan, offer-ing favorable planetary positions forreaching Jupiter via a Mars gravity as-sist, presented an attractive opportun-ity to combine both spacecraft in a

single, cost-effective launch. (TheProbe and Orbiter would separateshortly before reachinj Jupiter.)

HOwever, delays in the Space Trans-portation System schedule (see pages8-9) bave made it highly unlikely thatthis combined mission could belaunched in 1982. Nevertheless, thebasic Project Galileo objectives willstill be achieved through separatelaunches of the Probe and Orbiter(similar to the recent Pioneer Venusstrategy). This will be done by launch-ing the Orbiter in tearly 1984, whenMars is again available (although not inas favorable a position) to provide agravity assist. The Probeattached tothe Probe Carrier, a new spacecraft de-signed to relay radio signals from theProbe back ,to Earthwill then belaunched a few weeks later. Arrival ofthe Probe will be scheduled so that theOrbiter may view and characterize theProbe entry.

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Inventors have experimented for decadeswith large parachutes designed to lowerntire airplanes or detachable aircraftcabins to safety. Above: A November1929 Russell Parachute Company adver-tisement described its "Valve" parachuteas "The 'Lifeboat' of the Air."

chute pack carried on the person, andis credited with inventing the ripcord.

The first "official" parachute jump .

from an airplane flying at full speedwas made..on March .1, 1912, whenCapt. Albert Berry. iumped from a

Benoist biplane over Jefferson Barracks,Mo. Capt. BerriPwas.not an Army avia-tor, but a civilian professional vira-chutist. -(Early aeronauts and balloonjumpers often used the title "Captain.")

The Parachute in World War IDuring World War I, the parachinewas used successfully by military aero-nauts on both sides Oho were forced,to leap from the baskets of tetheredobservation balloons attacked by en-emy aircraft. Despite improvements inparachutes, few were used by 'Alliedairplane pilots during the War. By 1918,German aviators began using a staticline parachute, designed by Otto Hei-necke, that was carried on the air-plane. Many Germansincluding thefamous ace Ernst Udet, who bailed outof his Fokker in the summer of 1918saved their lives with this parachute.

Allied pilots began demapding para-chutes, too. Developtnent of a para-chute compact enough to be carriedaboard small pursuit airplanes beganin earnest.

The Parachute Comes of AgeIn 1918, experiments were begun atthe U.S. Army's McCook Field nearDayton, Ohio, to perfect a h.( e freefallparachute that could be worn pn thebody. Floyd Smith and Guy Ball, para-chute pioneers, are credited with de-

Alt & Spam May. June 1980 011

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World War II saw the first use of parachutes to swiftly deploy large numbers of Soldiersand equipment. Both Axis and Allied paratroopers figured prominently in several keycampaigns. Inset above: Heavily laden U.S. Army paratroopers, their faces blackenedfor combat, 'chute up for the invasion of Normandy in June 1944. Above: Parachutesand airborne troops cover a drop zone as an entire battalion of the U.S. Army's 82ndAirborne Division simulates an aerial assault during the 1950s.

veloping the Army Type A parachute,which was a great improvement overall previous types. The simplified ArmyType S thm followed the Type A wasthe basis fbr all modern personnelparachutes. Parachute containers be-came available in three basrc typesback, seat, and lap packwith thedetachable chest pack coming later.

Lt. Harold R. Harris is credited withmaking the first military emergencyparachute jump from an aimlane inthe United States over McCook Fieldon October 20, 1922. Shortly there-after, a doh was founded at McCookField with membership limited Lo air-men who had made succecsful emer-gency parachute jumps. ThiS groupeventually evolved into the CaterpillarClub, administer by the Irving Air.Chute Company. Leslie Irvin, founderof the company, chose the silkwormcaterpillar for the.Club's namesake, asmany of the parachutes of the tinwwere made of silk. (Today, virtually allparachutes are made of nylon.) Since

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then, thousands of people haveproudly worn the Caterpillar Club lapelpin, showing that their lives have beensaved by a parachute.

Several interesting types of para-chutes were developed during the 1920sand '30s. The Russell "Lobe" type wasextremely stable and reduced swaying.The "Triapgle," invented by Major E. L.Hoffman, director of Army parachutedevelopment at McCook Field, wasnot only stable;but steerable, and hada forward speed of about 5-8 kilo-meters (3-5 miles) per hour. It was thefirst real steerable parachute designand was greatly favored by exhibitionjumpers.

The Parachute in World War llDuring World War II, scientific meth-ods and formal engineering techniqueswere Used to design new types of para-chutes in the United States, England,and Germany.

Parachutes saved thousands of air-men, lowered supplies and equipment

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to ground 'troops, and were used ex-tensively to drop flares. Thousandstsofdeadly mines dropped by parachutesank many ships. . .

The Germans were the 'first to useparatroops during World War II, ctrop-.ping them into Norway, the Lrew Conn-*tries, Greece, and Crete. Large-scaleAllied airborne operations in Sicily,Normandy, and Northern Europehelped speed the end of World War Il..

The Parachute TodayParachutes have saved more than

0 200.000 lives. Today, however, severaltypes of 'parachutes are used for Atari-ous purposes other than lifesaving.

The National Weather Service usessmall parachutes to lower radiosondeinstruments that have been carriedaloft by balloons, Parachutes slpw rac-ing cars and high-speed military andtest aircraft on landing. Many moderncombat aircraft carry a special para-chute in their tail sections to assist thepilot in recovering from a 4iin.

The United Statk and the SovietUnion have used parac ttes exten-sively in their space pro , ams, prind-pally for spacecraft recov . specialparachute system employin a. newly-ckveloped "disc-gap" type canopy was

-.used to lower the lander sections oftwo Viking spacecraft through the thin

.,. atmosphere of Mars in 1976 (see backcover).

The Soviet Union pioneered the useof parachute nwdk al teams that aredropped into remote areas to provideemergency medical service, In the

Above: A U.S. Air Force McDonnell-Douglas F-15 Eagle jet fighter deploys a tail.mounted parachute to aid in recovery from a spin. BeWw: Many high-speed let aircraft,(like the U.S. Air. Force North American F-100 Super Sabre Interceptor shown In this1950s photo, usilmg

triggered a new variety of sport parachuting called "canopychutes to shorten their landing rollout. Left: Advances in modern

parachute technolorelative work," in which skYdivlb maneuver gliding parachutes relative to each otherto make formations II,ke this five-canoft stack.

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United States, smokejumpersair-borne firefightershave been para-chuting into remote forest and grassfire areas since 1940.

SkydivingSkydiving, as present-day sport para-chuting is called,.combines the exhilar-ation of flight completely free ofmechanical assistance with the .capa-bility to land on a predetermined spotfrom thousands of meters in the air.The development of safe, simple, reli-able equipment allowed parachutingto become the popular Tint it is

today. Since the late 1950s, scores ofthousands of adventurous athletes havetaken up skydiving. National and inter-national competitions have developed,and in 1)62, James Arender won thefirst world championship for the UnitedStates.

Now, guided by the U.S. ParachuteAssociation and similar national Organ-i/ations in many foreign countries, thesport has grown tremendously. Allover the world, men and women areapproaching the age-old dream ofhuman flight. They swoop through thesky at speeds up to 320 kilometers(200 miles) per hour, wearing small,efficient deceleration devices thatscarcely resemble conventional para-chutes, but which make possible pin-point precision landings after morethan a minute of freefall. The tradi-tional round parachute canopies arerapidly being replaced by a variety ofrectangular configurations called"squares," whichs create aerodynamic

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lift in a manner similar to an airplane'wing.

Today, with more than 25,000 activeskydivers, the United States is a worldleader in.the sport.

ParachuteTechnology

A parachute is basically a de-vice for adding to the resistanceof a body moving through theair.

Parachute operation involvesthree phases: deployment (can-opy and line extension), inftation,and descent. Parachute inflationactually occurs from the top(crown) of the canopy to thebottom (skirt). As air rushes intothe-canopy, a ba:l of air is formedin the top. This ball spreads out-ward until the canopy is com-pletely inflated. Everyone hasfelt the pull or drag of an openumbrella on a windy day. At acertain velocity, when the dragof the canopy equals the weightof the load, a "terminal veloc-ity" k maintained.

Parachutes may be designedwith a variety of features, de-pending on the intended use andother factors such as weight ofthe load, terminal velocity, anddesired rate of opening.

Air & Space, Mar.-Apr. 1980

Student Activity41,

parachute engineers'test parachutesfor many things----for example, rate

of descent, strength, opening reliabil-ity, glide angle, stability in air turbu-lence, degree .of oscillation (how farthe suspended payload swings fromside to side), and the time and alti-tude required for the parachute toopen.

The results of these tgts usuallydepend on several variables, scich asthe canopy's shape and size, fabricporosity, line length, suspendedweight, and atmospheric conditions(temperature, humidity, gustiness).

Some of these tests are easy toduplicate with small, Simple para-chutes made.from household materials.DiVide students into small groups,each group performing its own tests.

Test No. 1: Rate of DescentSet up a procedure for dropping a

parachute at least four timesprefer-ably in calm air. Do each drop exactlythe same way, from the same height,at the same place. Measure the: dis-tance the parachute descerids. Make acopy of the graphs shown on this page.On the Descent Times graph, recordthe.duration of each parachute descent.Calculate the rate of descent in metersper second (meters of descent dividedby duration of desceht) for eaCh drop.Record the results on the Rate of De-scent graph. Compare results Withthose of other groups.

ExampleA parachute made frprn a square offacial tissue loweN a single paper clipa distance of 1.8 meters in 4 seconds.

Rate of descent V

distance droppedtime to drop

Test No. 3: PayloadRate of DescentTry different weights as the payloadfor the same parachute canopy. Recordthe descent times for each payloadwhen parachuted from the same height.Calculate the rate of descent for eachpayload and graph the results:

Test No. 4: Canopy Shape vs.Rate of Descent

. Ask students to calculate the dimen-sions of different canopies with thessame area but different shapes ((orexample, a regular pentagon, square,equilateral triangle, and circle). Repeatthe drop tests with each canopy (usingthe same weight, dropped from the'same height) and calculate the rate ofdescent for each. Record and graphthe results.

Weighs vs.

1.8 meters 9

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= .45 meters/second

What kind of variables do you thinkdetermine the rate of descent? .Whatis the importance of averaging the re-corded times?

Test No. 2: Porosity vs. Rate of DescentConduct a semnd parachute drop ex-periment using parachutes made fromdifferebt materialsfor example, oldsheets or pirowcases, plastic dry clean-er bags, reir forced tissue paper, nylon,and silk. viake each parachute thesame site and shape as the others.Drop each parachute at least fourtimes. Calculate the rate of descentfor each canopy. Record the data oncopies of the graphs; compare results.

Air &Space,Mar.-Apt.1980

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Making a ParachuteFurnish each group .with a sheet offilm plastic. (Dry-cleaning bags slitdown one side work well.)

Instruct students to make a. six-sidedparachute canopy by cutting the plas-tic !nto a regular hexagon. Students .

should carefully cut hexagons withscissors or a modeling knife.

Tape a piece of nylon sewing threador light string to each corner gf the

, canopy. The length of the suspensionlines should be at least 0.7 times thecanopy diameter.

Hold the corners of the canopy to-gether. Pull the free ends of the sus-pension lines together. Make sure thelines are the same length, then tie theirfree ends together with a single over-hand knot.

Tie a washer, nut, or other smallweight to the knot.

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by Gregory P. KennedyAssistant Curator

Department of Space WeExploration, NAS

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payloads launched into space todate, whether they were manned

spacecraft, scientifidlsatellites, applica-tions satelliteS, or planetary probes,have had ryne thing in common: theywere bo stecJ by expendable launchvehicl The use of expendable 'launchvehi es has been one of the principlere .ons for the high cost of space flight.

NASA is currently working on a re-usable .Space Shuttle Orbiter that willbe able tti deliver payloads to Earthorbit at a lower cost than he single-use boosters now in service. (Seelanuary-February, March-April, andMay-June 1979 Air & Space.) The SpaceShuttle Orbiter represents a new typeof yehicleoneAhat must perform thefunctions of rocket, spacecraft, and air-craft during different-phases of itsfligh t.

Recently the Space Shuttle Orbiterprogram (now termed the Space Trans-portation System) has been plagued bya series of -setbacki and delays, manyof which can be attributed to the com-plex nature of this vehicle.

During ascent, the Shuttle is pow-ered by two Solid Rocket Boosters(SRBs) and three Space Shuttle MainEngines (SSMEs). The SSMEs aremounted at the base of the Orbiter

. and burn lkjuidhydrogen-and liquidoxygen, both of which are, carried in.the External Tank (ET1. Each sstsArgenerates a rated sea-level thrust of1,668,089 newtons (375,000 pounds)and tan be throttW from 50 percentto 104 percent of rated power.

In 1979, Shuttle engines being static-fired at the National Space TechnologyLaboratories in Mi,;sissippi ex 'encedfailures in die main fuel vs.'. .urbineseals, and noizle steerhorn, a sectionof hydrogen line ,nea,r the base of thenoiile. The most wrii)LIti problem wasin the noHle steerhorn, which 'failedbecause an incorrect welding wire(which was tiH) %Oft) w,15 mixed withthe «irrect strength wire. resulting ina severely weakened weld joint. Dur-ing i static firing on November 4, 1979,a weld on the steerhorn failed, result-ing in an oxygen-rich combustion inthe engine, which was extensivelydamaged. However, the various engineproblems have been analyied andmodifications have been made to theSSME. On December 17, 1979, the firstfull-duration firing of a cluster of threeSSMEs was made. Three-engine dukterfirings in February and March were alsosuccessful. In April, Performance FlightCertification tests on the SSME werestill in progress.

Unlike previous spacecraf(that wereprotected from the searing heat of

Alt & Space, May-lune 1960

SpaceShuttleUpdate-

..

Space Shuttle Orbiter Enterprise (above) was mated with an External Tank and twoSolid Rocket Boosters at the Kennedy Space Center in Florida for a facilities test Inmid-1979. This test helped clear the way for its sister ship Columbia to be launchedon its first mission into space, now scheduled for early 1981. Problems in uveral keyareas of Shuttl development forced delays in the launch schedule for Columbia, theworld's first reusable spacecraft. Enterprise served well as a teethed, but probably willnot be used on space missions.

atmospheric reentry by ablative heatshields (that, charred away as aerody-namic heating increased), the ShuttleOrbiter jc, covered with reusable sur-face insulation tiles made of coatedsilica fibers. Some 3U,922 tiles coverabouT 70- percent of the Orhir's ex-terior. The remaining 30 percent is cov-ered by coated Nomex heat-resistant'felt, reinforced carbon-carbon compos-ites, metal, and glass.

Each of the tiles must be installedby hand; .problems encountered dur-ing installation have caused the great-est delays 'to the Shuttle's schedule.During tests, it Was found that manyof the tiles failed when subjected totheir ultimate design load (1.4 timesmaximum predicted flight load). Theentire Thermal Protection System (TPS)of the Orbiter was reexamined, and allaccessible critical tiles pull-tested to1.25 times the highest predicted flightloads, Those that cannot be tested andthose that fail the test w ill be removedand the tile strength and/or bonding

system improved either by using adenser tile, by reconfiguring the tile"footprint" and thickness, or by im-proving the tile bonding techniclue.

Despite the preblems that have beenencountered, NASA officials have ex-pressed optimism that astronauts JohnW. Young and Robert L. Crippen willpilot Orbiter 102 Columbia on its 54-hour shakedown flight in early 1981.The %lid Rocket Boosters and Exter-nal Tank for the first flight are on handat the Kennedy Space Center in Florida.Last January, NASA completed a 30-hour systems test in Columbia. Thistest, called the Orbiter Integrated Test(OIT), teamed astronauts in Columbiawith flight controllers in Houston in acomputer simulation of the Shuttle'scountdown, launch, orbital flight, re-entry, and landing. Successful comple-tion of the OIT represented a majoraccomplishment in the process of pre-paring Columbia for flight because itverified compatibility of flight andground equipment.

WI

N.

A.

Above: A technician mounts ceramic-coated tiles on the Space Shuttle OrbiterColumbia. Almost 31,000 tiles make upthe thermal protection system that willabsorb the intense heat of air friction usthe Shuttle reenters Earth's atmosphereafter a mission in space. Each of the tilesmust be instaHed by hand; problems en-countered °during installation have caused

APoitmot the greatest delays to the Shuttle'sschedule. Below: Shuttle tiles have beenflight-tested on F-15 research aircraft atNASA's Dryden Flight Research Center,Edwirds, Calif. The tiles eventually willbe submitted to almost 1.5 timus Roe dy-namic air pressure that the Shuttle willattain during launch. Left: Shuttle crewsmay use a special kit to repair possibletile damage in orbit. The kit would con-tain two kinds of repair material: blocksof procured ablative material to fill in--large holes, and ablative paste to be viedas an adhesive for the replacementbkicks as well as a cure-in-place tiller forareas smaller than tiles. The blocks areprincipally silicone rubber which willablate from the hod of reentry. (ActualOrbiter tiles will not ablate during re-entry.) The cure-in-place ablator is apaste-like substance with fa silicon-rubberbase to be applied with an applicatorresembling a convent/onal caulking gun.

II

Work &MAW &Own

it49 to-

Student Activity'

nytime a spacecraft reenters

Earth's atmosphere, _heat shieldsare necessary to protect the astronauts.or instrument payroad from the healcreated br air friction on reentry. Onthe Orbiter, for example, surface tem-peratures during reentry may rangefrom 192.5 °K (3000 °F) on the noseand leading edges of the wings andtail, to 590 °.K (600 °F) on the trailingsurfaces. TIA systems used to protectspacecraft under such conditions util-ize regenerative cooling, ablative cool-ing, and the "heat sink" concept. Thefollowing activities demonstrate therelative weights and heat protectioncapabilities of simple heat shields.

MATERIALS for each group of students:flat-bottomed paper cupwa terwax candlescoat hangers

Activity OneHave each group of students AO itspaper cup, then hold it with a coathanger over a lighted candle. Have the-students me. sure and record the timeit takes for the "spacecraft" to ignite.As soon as it begins to burn, immersethe cup in water. Be carefulandremember to have water beside thecandles!

Activity-TwoHave each group drip wax over theflat end of the cup until the cup bot-tom is covered. Let the wax-coatedcup cool; weigh the whole system.Hold .the Op 'over the lighted candle.Meas.u.r.elnd record the, time to igni-lion. Be carefulremember, hot waxburns!

Activity ThreeHave each group cover the paper cuploosely with a sheet -of aluminum foil.Weigh the system, then hold it overthe lighted candle. Measure and recordthe time to ignition. Be carefu.lthehot foil can cause burns!

Activity FourHave each group pour about 1 centi-meter (3/8 inch) melted wax deep inthe bottom of each paper cup. Weighthe system. After the wax cools, holdthe cup over the lighted candle. Meas-ure and record the time to ignition. Becarefulremember, hot wax burns.

Note: Hold Ow cups the same distanceabove the flame in each experiment.

Questions1. \ Which system weighed the most?2. 'Which system withstood the heat

load the longest?

Air 8, Space,-May-June19i0

E

Women Parachutistsby Claudia M. Oakes

Assistant CuratorDepartment of Aeronautic% NASM

,The first parachute descent from anaircraft by a woman took place in

1799, when leanne7Genevieve Gar-nerin descended from a balloonflyingver-Franw. miTdatifeGerin, also

the first woman to fly sblo in a balloon,was the wife of André-Jacques Gar-

. nerin who, in 1797, became the firstperson ever to descend from an aircraftbx parachute (see page 4).

In 1815, Garnerin's niece, Elisa.Gar-

Left: Mrse Irene McFarlandbecame the first womanmember of the exclusive

Caterpillar Club (anassociation of those

who have para-chuted to safety

from aerial emer-gencies) after she

leaped from herdisabled air-

craft in 1925.

nerin, made the first of :her many de-scents from balloons in Paris. By 1836,she had parachuted from balloonsnearly 40 times..

Parachuting became a route to faillefor women in the early days of avia-tion. The most famous of -these daringparachutists--.and the one who madethe most signiiicant contribution to thedevelopment and widespread use ofparachuteswas a diminutive butspunky teenager from GranvilleCounty, N.C.

Her real name was Georgia Brown,but she was better known as. "Tiny"Broadwick. tn 1908, "Tiny" joinedCharles Broadwick's exhibitibn group,taking his, surname (as did all thegroup's members). "Tiny" agreed tomake six parachute descents per weekfrom a hot air balloon for $250, earn-ing $25 for each additional descent.Sometimes she would perform withmore than one parachute canopy, cut-ting them loose in succession as shedescended. "Tiny".. also jumped at

night with flares eitended about 60centimeters (2 feet) from either sideof her body.,

On Jurie .21, 1913, "Tiny" becamethe first woman to parachute from aheavier-than-air craft. Aviation pioneerGlenn L. Martin piloted the biplanethat carried "Tiny" to a height of about305 meters (1000 feet) above GriffithPark on the north side of Los Angeles,Calif. "Tiny" sat or), a trap seat at-tached to the wing; when she wasready to drop, she released a leverthat allowed her ,to fall. Her parachute operied perfectly, 'and shelanded on her feet.

In 1915, "Tiny" made a jump atNorth Island, San Diego, Calif., becom-ing the first pelson to demonstrate a.parachute to U.S. Government offials.

fir

For left: "Tiny" Broadvfick, the firstworken to parachute from an airplane,was also the fir.et person to papchutefrom a hydroplanp (floatplane). Hire sheIs preparing to drop -friim a hydroplane(piloted by aviation pioneer Glenn LMartin) into the cold waters of LakeMichigan In August 1913, aepart of the , -Perry Victory Centennial Celebration inChicago, III. Note her life. preservr forthe intentional water *ding. Near left:so/Pr"Tiny" also was the first person todemonstrate parachuteto VA. Govern-ment official% which shedid in 1915, oeSan Diego, Calif.' Her histik father andmentor, Charles Broadwici, In collabora- .

tion with alenn .Marttn, *lit her relativelycompact coat-type. parachutt

0h-

,She wore a "parachute coat" devel-oped by Challes.Broadwick in collo:.boration witJ clenn Marfin.

After ilnaking more than 600 de- .

scents, "Tiny" retired in 1922 becauseshe felt the novelty had- wOrn off forthe public.

.. -

Today, the exiseence*of women pagra."4- ,

chutists is still a /iovelty to some.However, .women parachutism.maymbe

efound jumpmastering paratroopers inthe U.S. Army's airborne divisions,testing, selling, and demonstratihgsport parachute equipment; workingin .parachute rigging lofts;, and tngi:neering new parachute designs. Theyalso compete in regional, national,Andinternational sport parachutingrneets(in separate women's categories); setand break national and world recorAscontinuing the legacy of pioneer:like Jeanne-Genevieve and Elisa Gas-nerin and "Tiny" Broadwick

,t1

. .

Abovef Sgt. Cheryl Stearn% the first oftwo women farrachsitists to join _theGolden Knights (U.S. Army. ParachuteTeam). holds 11 national and interna-tional parachuting tltle4+ three women'sindividual world parachuting record% andIs the current' Womensa Absolute WorldParachuting Champion.

Air & Spice, May-June 1960

If

4

OUTREACHby Kerry M. joels

Chiec.Education .Services Division

Manufacturing products for worldtrade requires making them compati-ble with world standards of measure-ment. But the anxiety that resultswhen a change in measurement sys-tems is imposed seems overwhelming.

Perhaps we need to -invent' a thirdsystem, the "big M." In this.third sys-tem of units we could find metric unitsthat are: rough equivalents of Englishmeasures, and .call them by commonEnglish names. Children could stilllearn the metric system, while adults;for the price of an extra line of print oncontaihers and packaging, would havean English equivalent.

For example, 500 grams equals\ about 1.1 pounds. If we call 1.1 pounds

M-pound, and charge 10 percentore for an M-pound than for an

English poimd, consumers would havehamburgers of almost the same size,and would not likely be able to tellthe 10 percent price increase fromnormal inflation. Shoppers.would com-prehend one M-pound of beef at$1.65 much more easily than one kilo-

The metrication movement in educa-tion has produced considerable reve-nues for textbook companies, head-aches for teachers, and very littlemetricatión for the United- States.There seem to be two basic approachesto the task of metrication: (1) thelengthy process of classroom educa-tion, and (2) the philosophy of quit-ting the English system "cold turkey"'and adopting the metric system outr\right. Neither approach has worked inCanada,'.'areat Brit in, or the UnitedAtes: It seemscomfortable a t changing the basic

t a

Thdtpeople aret few

unitl of lekgth, area, volume, and massapd Weight th.at they use daily.

Cc.mmon weights and measdres,.and their rplationships to prices, are

'1.e.itrned by 'habit. Homemakers knowthat one pound of beef ,makes four'hamburgers and codts, say,11.50. Buthow many homemakers know that 500grams of beef will make the samenurntier of hamburgers, and that $1.60

. would "be a fair price to pay for .t.ilat' amount?

gram of beef (or anything) at $3.30. .

The concept Auld carry over tootherweights and meapres. The literwould become an M-quart; four liters,an M-gallon (110 percent of a gallon)..The meter would become the Mlyard,and- 21/2 centimeters would etlual*.oneMinch (40 Minches to the M-yard).Adults would speak of M-gallons,Minches, M-quarts, M-feet, M-yards,and M-pouncN and would use meas-ures oitly slightly larger than conven-tional English units.

Some problems would arise, ofcourse. The kilometer would beComethe but speedometers wouldbe calibrated in kilometers per hour.Ninety M-rniles per hour would ectlial55 miles per hour.

We would haVe to make new rulersand scales, but manufactuiers wouldmerely produce metric goods, andcheck-ctut computers could tally Pricesand apply labels rather easily. Peoplestikl could use the. same familiar pro-portions of food in figuring porlionsand using recipes; estimate yard goods,carpeting, and building materials infamiliar terms; and permit industry to

'metricize for competition in .the worldmarket. .

This might be an off-beat suggestion.But how can we teach students if theirparents will never,let us .get into thesystem?

.d

The Spacearium. Shag.. of the National Air and Space Museum offers for sale a wide variety of high-

,

quality, reasonably priCed books, postess, and other items related to the explora-ion of the airand space. AN abbreviated list of books for sale appears below,

To order books, 'mark the. number ofcopies of each book you wish to pur-chase. Cut out or copy -this advertisementand mall with your check or money orderto

Program Coordinator, Dept. AS-580Room P-701National Air and Space Museumsmithsonlan InstitutionWashington, DC 20580(202)1381-4084

Please do not snd cash. Foreign ordersshould include $1.00 Or mit-order itemto cover air mail shipping.

Numberof copies

. .@ $ 3.25 Aircraft of the National

Alr and Space Museum.The catalogue of the Nibtional Aeronautical Col-lection. Par;er

® $ 2.75' Rockets, 'Missiles, endSpacecraft, of the Ns-

Alt & Space, May.June 1980

Banal Air and Space Mu-seum. The Catalogue Ofthe National AstronauticalCollection. Paper

.0 $ 5.20 Charles A. Lindbergh: AnAmerican Life, by Tom D.Crouch. Paper

The Artist In Spice, byJames Dean. The story ofthe commission of .artduring the U.S. spaceprogram. Paper

The Wright Brothers: Neinof Prometheus, RichardP. Hellion, ed.HardboUndPaper

.® $ .3.25

$16.25$ 7.20

i$18.75$ 8.20

Apollo: Yen Years SinceTranquillity Babe, RichardP. Hellion and Tom D.Crouch, eds. . .

FladboundPaper

11

g$ 3.75 U.S. Women In "Aviation.Through World War I, byClaudia M. Oakes:Paper

$ 6.20 Excallbur III:* The Storyof the P-51 Mustang, byRobert C. Mesh. Paper

$ 7.20 The P-80 Shooting Star:. Evolution of a Jet Fighter,by E. T. WOoldridge, Jr.Paper

Jet Age: Forty Years ofJet Aviation, Walter J.Boyne and Donald S.Lopez, eds.

,® $18.75 Hardbound$ 9.20 Paper

El Please send me FREE Information, about the Spacearium Shop's AviationRelic Series; World War posters; Imagesfrom Air and Space posters; Milestones ofFlight commemorative (philatelic) covers;and other Spabearlum Shop Items for sale.

NAME

ADDRESS

PITY

' STATE ZIP

A Mars 'Airplane?scientists consider an airplane

design that's definitelyout of this world

Folded into a compactpackage, a hypothetical MarsPlane enters the thin martianatmosphere using a protective heatshield, then a parachute, to decelerate

by Robert W. WolfeGeologist

Center for Earth and Planetary Studios, NASM

0 n July 20, 1976, Viking Lander 1set.. clown on Mars and, within

minuto, began transmitting our firstclose-up view of the Red Planet's sur-face. Slowly, the alien scene filled tele-vision screens. Scientists were elated.But with its footpads anchored in thefine red martian dust, Viking's visionwas limited. Scientists dreamed to seebeyond the cratered horizon, a mew4 kilometers (2 '../. miles) away,

if only Viking had wings, could fly,explore! But what could fly 'in Mars'told, thin atmosphere, having (at most)one percent of the density of Carth's?But wait that's at sea level. Planesfly high where the air is thin. Let's see:al 13 kilonwters (I 08,0( t0 feet), Farth'sair is as thin as the atmosphere nearMars' surface. We've flown that highin ,the North Anwrican X-15 and SR-71Blackbird--but they're too big, too

-heavy to send to Mars. Oh well, it wasjust a dream.

Our mythir al dreamer-- pi,rhaps en-thralled by high-speed flightprob-ably never heard of Mini-Sniffer, a small,light-weight RPV (remotely piloted ve-hicle) develryed by Dale Reed ofNASA's Dryden flight Research Centerat .1dwards,. Calif. Designed to cruisefor long periods and colleo samples 27kilometers (89,0(X) feet) high in thestratosphere, Mini-Sniffer has manyattributes of an airplane that could flyon Mars: light weight, a relatively largePayload capacity, .the ability to sustainflight and maneuver in thin air, and agreat range. Some of these capabilitiesactually would be enhanced in Mars'lesser gravity, about 38 percent that ofEarth. The potential of Mini-Sniffer asa Mars airplane was first recognizedby lose Chirivella, an engineer at

NASAN let Propulsion Laboratory in

Pasadena, Calif., with whom Reed cn-suIted on a matter related to Mir*Sniffer's hydrazine engine.

Engineers began thinking about thedesign of a Mars airplane based surthe.features -of Mini-Sniffer; out optimizedto fly in the martian atmosphere. Theycame up with a larger craft with awingspan of about 20 meters (66 feet).To fit within a conventional spacecraftfor transport 'to Mars, the airplane..would need to be folded into a muchsmaller package. How could this bedone? The airplane might use Astro-mastsprestressed beams that can becollapsed and later deployedfor thefuselage and for the wing and tailspars, and a folding propeller. The 13-meter (43-foot) Astromasts that carrythe magnetometers on the Voyagerspacecraft were stored in a containerless than 1/2:meter (1.6 feet) long.

Who would "pilot" the Mars air-.plane? The minimum time needed forthe airplane to transmit a message orpicture to Earth and to receive a replyis more than 8 minutes. Clea`rly, then,the airplane would need to pilot it-Self. The tasks of terrain avoidance andmaintaining the proper "flight enve-lope" would be the responsibilities Ofsophisticated instruments and compu-ters aboard the airplane. Acting onpictures and other information trans-mitted by the aircraft, controllers onEarth could periodically alter or updatethe flight path to restudy an area orto fly to a more interesting locale.

Today, there are no firm plans tosend an airplane to Mars. But one day,perhaps, these extraterrestrial flights offancy might become reality, greatlyextending the horizons of our, knowl-edge of the red planet.

Tail booms extend and lock In place;wings and tall unfold and lock; propellerunfolds and locks

Mars Plane releases from parachute;propellor starts to windmill

i 121 Air & Space, May-June1980

Back issues of Air & Space. are notavailable but articles may be orderedfrom University Microfilms Interna-tional, 300 N. Zech Rd., Ann Arbor,Michigan 48106.

This index applies to Volume 3 of Air& Space (1979-1930 school year, fiveissues, Septemlwr through May).'"

An index to Volumes 1 and 2 (March1978 through May-lune 1979) may befound on page 15 of the May-June1979 issue.

Aerial photography. Nov-Dec, pp. 6-7.Aerobatics. Nov-Dec. front cover, pp.

3-5, 8-9, back cover.Air transportation (Ind fuel efficiency,

lan-Feh, pp. 3-6..Alhert Einstein Spacearium, Mar-Apr,

p. 12.Apollo: Ten Years Since Tranquillity

Raw, Sept-Oct, p. 11.Fach issue, p. 2.

Byrd, Richard E. Sept-Oct, front cover,pp. 2-4,

Creating a new gallery at the NationalAir and Space Museum, Jan-Feb, pp.10-11.

Directory of Aviation/Space Education.Jan-Feb, p. 15.

Early flight. Jan-Feb, pp. 6-7.Forty Years of let Aviation. Sept-Oct,

p. 11.Galactic 'center (of Milky Way), the.

May-June, p. 15.Gossamer Albatross. Sept-Oct, p, 8.Kiter.. Mar-Apr, front cover, pp. 3-5.Lifting Bodies. Mar-Apr, front cover,

pp. 6-7.

INDEX-Lindbergh, Charles A. and Anne M.

Sept-Oct, p. 5.Lockheed Sirius Tingmissartoq. Sept-

Oct, pp. 5, 6-7 (model).Lunar and martian maps. Mar-Apr, p.

15.Lunar and planetary toponymy (feature

terms), Mar-Apr, pp, 10-11, backcover.

Mars Airplane. May-June, pp. 12-13.Multiple Mirror Telescope, Nov-Dec,

pp. 12-13.NASM galleries

Air Transportation. Jan-Feb, pp. 3-5.Early Flight. Jan-Feb, pp. 6-7.Exploring the Planets. Jan-Feb, pp.

10-11.Ole Miss (1935 Curtiss Robin endur-

ance flight). Jan-Feh,.frorrt cover.Outreach. Sept-Oct and May-June, 11;

other issues, p. 15.Parachutes: May-lune, front cover, pp.

3, 4-6, 7, 10, hack cover.Pioneer (unmanned spacecraft) en-

counter with Saturn. Nov-Dec, pp.10-11.

Planets, conjunctionMar-Apr, p. 15,

Project Galileo (planned unmyfnedmission nto Jupiter). May-June, p, 3.

Regional Resource Persons. Nov-Decand May-June, p. 15.

Sky maps (star charts). Each issue: Sept-Oct, p. 10; other issues, p. 14.

Solar power satellites. Jan-Feb, frontcover, pp. 12-13.

Solar system statistics (table). Nov-Dec,p.11.Correction. lan-Feb, p. 2.

Space Shuttle OrbiterLifting bodies as antecedents to, Mar-

Apr, pp. 6-7.

of nakeu-eye.

Small Self-Contained Payload (SSCP)or Getaway Special (GAS) Pro--gram. Sept-Oct, p, 9.

Student activity (heat dissipation).May-June. p. 9.

Update. May-June, pp. 8-9.Spacearium Shop, The (advertisement).

Mar-Apr, p. 13; May-June, p, 11.Special Presentations Calendar. Nov-

Dec, p. 15.Student activities

Loop flip book. Nov-Dec, pp. 8-9.Parachutes. May-June, p. 7.Planetary feature tel ms. Mar-Apr,

hack cover.Polar coordinates, Sept-Oct, p. 4.Scientific notation and astronomical

distances. Nov-Dec, p. 11.Space Shuttle. May-June, p. 9.Vin Fiz Board Game. Jan-Feb, pp.

8-9.Surveying Antarctica, Sept-Oct, front

cover, pp. 2-4,Think Along (each issue, back cover)

with the aerospace engineersabout how to land a spacecraft on

Mars. May-June.with the aircraft designers

.what makes a good aerobatic air-plane? Nov-Dec.

with the astronomersabout solar ups and downs. Jan-

Feb..

with planetary scientistsabout Mars' mysterious polar ice-

cap. Sept-Oct.about planetary feature terms.

Mar-Apr.Vin Fit Board Game. Jan-Feb, pp. 8-9.Women in Aviation (U.S., 1880 through

World War l). Mar-Apr, pp. 8-9.Women Parachutists, May-June, p. 10.

Mars Plane pulls out of dive and startsengine for cruise mission, an extendedsurvey of the martian surface

Air & Space, May-June 1900

_L

.

4

as,

Martians examining an alien airplane'? No, lust the ground crew preparing Mini-Snifferfor a hIgh-allitude atmospheric sampling flight at NASA Dryden Plight Research Center,Edwards, Calif. Minl-Sniffer's hydrazine engine, developed for use In spacecraft, enablesthe Mini-Sniffer to fly at extreme altitudes and perform a variety of missions. An air-plane concept using Mini-Sniffer technology is under consideration for future explora-tion of Mars.

13 1 4

This cIrcie represents the night sky as itappears in late July at 9:00 p.m.or early August st 9:00 p.m. .

Turn map to the directionyou are facing. The cen-ter of the map is thepoint directly overyour head.

a

PHASESOF THE MOONNew Moon: July 12,

August 10First Quarter: July 20, August 18Full Moon: July 27, August 25Last Quarter: July 5, August 3

me. ........ e

by T. H. Callen IIProduction Specialist

Albert Einstein Spacearium, NASM

One of the perennial splendors of thesummer sky Is the Milky Way, part of thegalaxy In which we live. It appears as abroad band of diffuse light because weare looking at this vast disk of stars edgeon from the inside. Other summer star-gazing treats, also part of the Milky Way,include the billowing star clouds of Scor-pius and Sagittarius, now well placed forobservation by unaided eyes or withbinoculars and telescopes. Casual inspec-tions of this region with binoculars ortelescopes reveal several nebulae (glow-ing clouds of hydrogen gas and dust),'areas actively producing new stub. Such

NIHON

914Viod

HaddICI

July-AugustSky Map

Dix: GalaxyOCI: Open clusterDbl: Double starNb: Nebula

Overhead+

. .

e, .:fit AI.

i°/

Antares .196.

.0

...SCORPIUS

tiptDbl4.

SOUTH

ov4Ir'

surveys also bring to our attention openor galactic clusters, compact collectionsof several hundred stars. Such clusters ofstars are believed to have formed at thesame time from the same nebula.

Other star clusters, globular clusters,also are visible In the night sky, appear-ing like fuzzy white balls through binocu-lars or small telescopes. Globular clus-ters typically contain about 100,000 stars,and are the oldest objects known In gal-axies. In 1918, American astronomer Har-low Shapley noted that these globularclusters tend to be concentrated In onehalf of the sky, one third of them in thedirection of the constellation Sagittarius.Having determined their distances fromthe Earth, Shapley correctly theorizedthat the center of our galaxy lay In thatdirection. Study of other splral galaxies

446,

Air 8 Space, May-June 1980 14

8+.'

ao4

e

E-1cn4.1

Sky map byD. David Batch

Abrams PlanetariumMichigan State University

NSTA, published inScience and Children,

reprinted by permission

showed that their globular clustersformed a halo around their galaxy's nu-cleus. We know today that our star, theSun, Is about 33,000 light-years (3.12 X10" kilometers, or 1.94 X 10" miles) fromthe center of the Milky Way Galaxy.

This year's annual Perseid meteorshower, peaking on August 11, should bespectacular, as the new Moon will insuredark skies. (To observe the shower, It Isbest to find a site away from city lights.)Weather permitting, up to 50 meteors perhour may be visible 'to a single.observeras they streak Into the Earth's upperatmosphere at speeds of about 60 kilo-meters (37 miles) per second and burnup, While watching this event, try to keepIn mind that the particles causing thiscelestial fireworks display are only aboutthe size of sand grains!

15

40

30

20

10

THE GALACTIC CENTERAugust 1,1980 9:00pm

111

0SAGITTARIUS SCORPIUS

0130 40 150 160

SOUTH EAST

170 160 190 200

SOUTH

The Galactic Centerby T. H. Callen II

Production SpecialistAlbert 'Einstein Spacearium, NASM

The diagram above shows the location ofthe center of our Milky Way Galaxy, rela-tive to the constellations Sagittarius andScorpius, at about 9:00 p.m. on August 1,1980. We might expect the region of thesky near the galactic center to be quitebrightother spiral galaxies show bright,active regions in their nuclei caused hyan, as yet, unexplained process. How-

pever, we receive only about one ten--billionth of the light we would expect to

see from the center of our Galaxy. Whilethe distribution of interstellar matter inour Galaxy is essentially thin, there isenough dust and gas in the space be-tween us and the galactic center-33;000light-years distantto scatter or absorbmost of the light from this region. Thescale- along the bottom of the diagramshows 'azimuth, or compass heading, indegrees, while the scale along the dia-gram's side shows altitude, or heightabove the horizon, in degrees.

Compare the diagram above with theradio view of the galactic center (below).Each contour on the radio map repre-sents an interval of radio signal intensityat a wavelength of 11 centimeters (4.3

;

Inches, or 2.7 X 10' hertz). The galacticcenter lies in the direction from which themost intense radio energy is beingemitted. The map was, plotted by com-puters linked to the 42.7-meter (140-foot)radio telescope of the National RadioAstronomy Observatory (NRAO), GreenBank, W. Va.

To orient the radio map to the visiblesky diagram, rotate the map clockwiseuntil the arrow just below it points straightdown.

This map shows two coordinate sys-tems. The traditional celestial coordinatesystem used by most astronomers meas-ures Right Asqpnsion (R.A.) in hours andminutes (from 0 to 23 hours 59 minutes)from an arbitrary point in the sky, andDeclination (Dec.) In degrees and minutes(from 0° to -±90°) above or below theplane of the Earth's equator. The galacticcoordinate system uses Pi for longitudein degrees (from 0° to 3600) around theplane, or equator, of the Milky Way Gal-axy, and bi for galactic latitude in de-grees (from 0°..to ±-901 above or belowthis plane. The starting point for this sys-tem is the galactic center. In the galacticcoordinate system, the position of thegalactic center is /" = 0°. and b" = 0°;in the celestial coordinate system, R,A.17 hours 42.2 minutes, Dec. 28° 55'.

()"

Free Presentations onAviation and SpaceAvailable

NASM has trained nine educators togive presentations in their communitieson the history and significance ofaviation and space.

The educators participated in anexperimental Regiohal Resource PersonTraining Session held in July 1979 atNASM in Washington, DC. The pro-gram, new last year, included an inten-sive course in the history of aviationand space and a review of teachingmethods. The educators have returnedto their communities where they willteach other 'instructors the history ofaeronautics and astronautics and waysto integrate these subjects into theschool curriculum.

These Regional Resource Persons willmake free presentations to teachers,students, and to the general public:

Darrell E. Asbury, Morgantown HighSchool, Morgantown, W VA;

G. Courtney Chapnian, Ohio StateUniversity, Columbus, Ohio;

Walter Dinteman, Camden County. College, Blackwood, NJ;

Virginia Ellett, Mathematics and Sci-ence Center, Richmond; VA;

Dr. Fred Hofkin, 'School District ofPhiladelphia, Philadelphia, PA;

Sister Jean Margaret Kaindl, MotherGuerin High School, River Grove, IL;

Richard Rooney, New Castle CountySchool District, Wilmington, DE;

Lockhard Smith, Jr., Wentworth In-stitute, Boston, MA; and

Sherman Taffel, Lake Clifton 'SeniorHigh School, Baltimore, MD.

For more information on presentations in your. cofnmunity, contact theRegional Resource Person in yourarea. For further information on. theRegional Resource Person Program,contact Janet Wolfe, Education Serv-ices Division, National Air and SpaceMuseum, Washington, DC 20560.

ILLUSTRATION CREDITS

Tront cover: Apollo 17, NASA; sport para-chutist by M. Anderson Jenkins, courtesy U.S.Parachute Association. Page 2: NASM Collec-tion, Page 3: NASA, Pages 4-5: NASM Collec-tion. Page 6: Sport parachutists by Andrew C.Kpech; all others, NASM Collection, Page 7:Art by Janet K. Wolfe, NASM. Pages 8-9:NASA. l'age 10: Cheryl Stearns by U.S. ArmyParachute Team; all others, NASM Collection.l'age 11: NASM Collection. Pages 12-13 Artby Robert W. Wolfe, NASM; photos, NASA.Page 11: Galactic center art by PatoWood-Nide and T. II, Callen II, NASM; radio mapcourk:sy of National Radio Astronomy Obser-valory, Green Bank, W. Va. Back cover: NASA,

Air & Space, May-June 1980

THINK ALONG WITH THE AEROSPACE ENGINEERSd about how to land a spacecraft on Mars

by Howard T. WrightDirector for Projects

NASA Langley Research Center

Planning the Viking missions-4osearch for life on Marsraised manytechnical problems that had to besolved for the first time. For example,what would be the best way of slow-ing the two Viking Landers for softlandings on Mars?

Unlike Earth's Mqpn, Mars has anatmosphere, albeit a thin one. Vikingengineers decided that the Landersshould, enter the thin martian atmo-sphere in a manner similar "to that ofmanned spacecraft reentering theEarth's atmosphere.

Each Lander would, enter the uppermartian atmosphere at 16,000 kilo-meters (10,000) miles) per hour; thecraft's blunt ablative heat shield woulddissipate the tremendous heat of aero-Aynamic friction. (Allowing a thin layerof material on a surface to char awayas atmospheric heat builds up is calledabhtion. Gases generated by the abla-tive process help insulate the space-craft from further heating.)

After slowing considerably, thespacecraft would deploy a parachuteat about 5700 meters (18,700) feet)above the surface. At 1400 meters(4600 feet), the Lander would jettisonthe 'parachute canopy; three rocketthrusters would brake the Lander dur-ing the last segment of its descent.

Viking engineers, seeking simplicity,ease of construction, and high reli-ability, chose a clisc-gap-band designfor the Viking Lander parachute can-opy. The central disc portion of thecanopy would provide high aerody-namic drag; the gap-band, excellent.deployment characteristics and canopystability.

The parachute system was 16 meters(53 feet)- in diameter, 30 meters (98feet) long, and weighed 50 kilograms(H 0 pounds), including the mortar de-ployment system. It was designed to

be deployed at velocities above Mach2 (2510 kilometers, or 1560 miles, perhour) and to decelerate a 1134-kilo-gram (2500-pound) payload to 97 kilo-meters (60 miles) per hour within oneminute. The parachute had to with-stand biological sterilization: the entireparachute system was "cooked" at135 °C (275 °F), for 40 hours beforebeng placed in the spacecraft. Thecanopy was packed to a density ofabout 705 kilograms/meter' (44pounds/foot3)about the density ofmaple wood!

After being "cooked," packed in its56- by 38-centimeter (22- by 15-inch)canistc i. for more than 21/2 years, andfrozen in deep space for a year, this

____m;osoft

In 1972, NASA drop-tested the Vikingparachute with a 907-kilogram (2000-pound) weight (left) from a 5-57 aircraft15.2 kilometers (50,000 feet) high. Tosimulate parachute deployment in Mars'thin atmosphere, NASA flew the world'sfour largest successful balloons to 36.3kilometers (119,000 feet), from whichrockets flew the parachutes to Mach 2openings at 42.7 kilometers (140,000tee%

17-kilogram (38-pound) piece of clothwas expected to perform flaWleSsly andwithstand a 7260-kilogram (16,000-pound) opening shock load.

It did. On July 20, 1976, VikingLander One touched down successfullyon the Chryse Planitia (Plains of Gold)on Mars. Lander Two landed on UtopiaPlanitia on September 3, 1976. Since1976 the Landers have continued togather a wealth of information thathas forever changed mankind's under-standing of the red planet.

A Viking Lander Proof Test Capsule,a real Viking spacecraft used in groundtests before and during the flights, ison display in 11/41ASM's Milestones ofFlight gallery.

NATIONAL AIR AND SPACE MUSEUMTHE SMITHSONIAN INSTITUTION

WASHINGTON, DC 20560Jan W. Steenblik. Editor, Air & Space

Room P-700

Non-Profit Org.U.S. Postage

PaidPermlt No. 3055Beltsville, MD