oao-c press kit

8/8/2019 OAO-C Press Kit

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Howard G. Allaway(Phone: 202/755-3680)Kenneth P. Senstad (GSFC)(Phone: 301/982-5566)RELEASE NO: 72-156

NATIONAL AERONAUTICS ANDSPACE ADMINISTRATIONWashington,D. C.20546Phone: (202) 755-8370)

F O R R E L E A S E :AM's Thursday,August 17, 1972

NASA TO LAUNCH HEAVIEST ASTRONOMICAL OBSERVATORY

The heaviest and most complex U.S. unmanned spaceobservatory, designed to seek answers to some of the fun-damental questions concerning stars and interstellar matter,is being readied for launch by NASA from Kennedy SpaceCenter, Fla., aboard an Atlas-Centaur rocket no earlierthan August 21.

Called Orbiting Astronomical Observatory-C (OAO-C),the 2,200-kilogram (4,900-pound) automated spacecraft willview the heavens with a precision and clarity never beforepossible. It will be able to point its sensitive ultraviolettelescope the largest ever orbited at an object thesize of a basketball seen from a distance of 650 kilometers(400 statute miles) for periods up to one hour.

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OAO-C, to be launched into a 740-kilometer (460-statute-mile) circular orbit, is the fourth and final space-

craft in the series initiated by NASA in 1959.After orbit is achieved the observatory will be renamed

Copernicus in honor of the Polish astronomer NicolausCopernicus (1473-1543), recognized as the father of modernastronomy. (Next year marks the 500th anniversary of hisbirth.)

The primary astronomical eye of OAO-C is an 82-centi-meter (32-inch) diameter reflecting telescope housed in thecentral tube of the three-meter (10-foot) long cylinder-shaped spacecraft. It will provide, via radio signal, spec-tral readings in ultraviolet light. This portion of theelectromagnetic spectrum is not visible to ground-basedobservatories because of the obscuring effect of theEarth's atmosphere. The instrument is provided by PrincetonUniversity.

Its primary objectives will be (1) to study the inter-stellar absorption of hydrogen, oxygen, carbon, silicon,and other common elements in the interstellar gas; and(2) to investigate ultraviolet radiation emitted from so-called young hot stars (early-type stars) in wavelengthregions between 930 and 3,000 Angstroms.

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The second instrument carried by OAO-C was providedby England's University College, London, under the spon-sorship of the U. K. Science Research Council. It consistsof three small telescopes and a collimated proportionalcounter, to study X-ray sources in space, at various wave-lengths up to 70 Angstroms.

One of the major discoveries of space exploration hasbeen the finding that many objects in the universe emitX-rays. It had long been known that the sun emittedlow intensity X-rays, and astronomers assumed that otherstars emitted proportional amounts that could not bedetected from Earth.

However, sounding rockets and NASA's Uhuru satellite(Explorer 42), launched December 12, 1970, have discoveredmore than 200 X-rays sources in the universe. These sourcesgive off enormous amounts of energy. They oxist in suchdiverse regions as the Magellanic Clouds, the Crab Nebula,galaxies and even in some areas of the sky where no visibleobject can be found. The enormous energy they emit suggestenergy processes heretofore thought impossible.

The University College, London experiment will seek newX-ray sources, better locate and map sources already known,and help open the door to a better understanding of thesecelestial phenomena.

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The mos t obvious exterior physical difference betweenOAO-C and OAO 2 is the inclusion of a more effectivetubular sun baffle to allow operation of the Princetontelescope in daylight, additional baffles for the UniversityCollege, London experimen t, and two forward looking startrackers.

The NASA program of Orbiting Astronomical Observatorieswas initiated in 1959. The first OAO, launched April 8,1966, failed after only three days in orbit because of amalfunction- in its power system and high voltage arcingin the star tracker system. Although it operated onlybriefly, basic engineering results were obtained thatproved the technical feasibility of the OAO concept.

OAO 2, launched December 7, 1968, has operated con-tinuously since then far beyond its expected lifetime.It carries ultraviolet viewing instruments provided bythe University of Wisconsin and the Smithso nian Institu-tion's Astrophysical Observatory.

Its scientific results have bee n impressive. It hasadded a new dimension to astronomy by opening a large portionof the electromagnetic spectrum for astronomical investigationsfrom space. It has made major contributions to man's knowledgeof galaxies, stars, the solar system, and Earth's upper atmo-sphere .

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It has also made major observations during its life-time of comets, a nova, and most recently, in May this year,a supernova. (See section "OAO 2 results," pp. ).

The third observatory OAO-B was launched Novem-ber 30, 1970. It was designed to conduct astronomical andastrophysical research, by spectrophotometry, of ultra-violet emissions from celestial objects deep in space.However, its 96-centimeter (38-inch) telescope neveroperated because the Atlas-Centaur shroud failed to deployand orbit was not achieved.

Overall, the OAO program, as the nation's pioneeringspace astronomy observatory series, has achieved impressivesuccess. According to OAO Deputy Project Manager and Pro-ject Scientist, Dr. James E. Kupperian, Jr., "OAO hasopened the door to advanced space astronomy programs of thefuture by proving that meaningful space astronomy investi-gations can be conducted from automated unmanned observatories."

"Of particular significance," he says, "is the factthat the space environment does not degrade observinginstruments. Earth-bound telescopes are subjected to severedegradation due to environmental pollution and the effectsof gravity factors not present in space.*

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In summary, he says, "In terms of scientific achieve-ments it has moved us closer to finding some of the ultimateanswers to the basic problems of cosmology."

OAO-C's pointing accuracy the most precise everdeveloped approaches the pointing accuracies neededfor future large space astronomy programs such as the NASALarge Space Telescope (LST).

Currently, the Marshall Space Flight Center, Huntsville,Ala., is investigating the feasibility of the LST. Thisobservatory will have the capability of viewing to the edgeof the of the universe with its proposed three-meter (10-foot)mirror. Present plans tentatively call for launching thisenormous viewing instrument, weighing more than 9,000 kilo-grams (20,000 pounds), from the Space Shuttle in the early1980s.

The OAO program is directed by the Office of SpaceScience, NASA Headquarters. Project Management is charged

to the Goddard Space Flight Center, Greenbelt, Md. Goddardis also responsible for spacecraft communications andtracking under direction of the NASA Office of Trackingand Data Acquisition.

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The Grumman Aerospace Corp., Bethpage, N. Y., has beenprime contractor for all OAO spacecraft. Prime contractorfor the Atlas-Centaur rocket is General Dynamics-Convair,San Diego, Calif.

Management of the Atlas-Centaur launch vehicle isunder the Lewis Research Center, Cleveland, Ohio. Launchoperations are conducted by the Unmanned Launch OperationsDivision of the Kennedy Space Center, Fla.

The Princeton Experiment Package was built by SylvaniaElectronics Systems, Needham, Mass., and the Perkin-ElmerCorp., Norwalk, Conn. The University College, London X-rayexperiment was built by a group of firms in the UnitedKingdom, including Pye Telecommunications, Cambridge;Elliott Brothers, London, and Rank-Taylor-Hobson, Hertfordshire

More than 1,000 subcontractors and vendors from through-out the United States have participated in the OAO program.

(END OF GENERAL RELEASE; BACKGROUND INFORMATION FOLLOWS)


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QIO-C 3 F A C S C H A P T


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LOW-THRUSTJET (-YAW) SUN BAFFLEBSST LIGHTBAFFLE

STARTRACKERNO. 5

SOLAR(4)PRIMARYHIGH-THRUSTJET (-YAW)

STARTRACKERNO. 3

LOW-THRUSTJET (+ ROLL)SECONDARYHIGH-THRUSTJET (+ YAW)INERTIALBOOM LATCH

INERTIALBOOM (2)

VHFANTENNA

AUXILIARYSOLAR PADDLE (4) STARTRACKERNO. 2PRIMARYHIGH-THRUSTJET (+ ROLL)

UHFPITCHFORKANTENNA


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GsC,I8Os -05


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THE PRINCETON EXPERIMENT PACKAGE

The basic structure of the Princeton Experiment Package(PEP) is a 100-centimeter (40-inch) diameter cylinder, aboutthree meters (10 feet) long, weighing about 450 kilograms(1,000 pounds). The primary mirror is 82 centimeters(32 inches) in diameter. The experiment also includes.guidance optics and detectors to generate precise signalsneeded to point the spacecraft.

To reduce weight, the primary mirror was made fromthin, fused, silica ribs assembled in a pattern much likean egg crate. This reduced mirror weight to 47 kilograms(105 pounds). According to project officials, a similarsolid glass mirror would weigh about 160 kilograms (360pounds).

The mirror is held in position during launch by aspecially designed vibration isolation system to separateit from three quartz rods which will keep mirror temperaturesuniform. After orbit is attained, and just before theexperiment is activated, the mirror will be releasedautomatically and moved against the quartz rods.The PEP spectrometer is isolated from the telescopestructure by a suspension system using a combination of

viscous and spring dampers. This protects the sensitivedevice from launch shock and vibration and keeps itthermally isolated from the telescope.PEP will be able to view stars down to the sixthmagnitude in ultraviolet light. Initially, PEP willlook at 47 young hot stars in our galaxy. PEP will useabout 90% of the OAO-C viewing time, normally 27 days amonth.In operation, ultraviolet energy from a star beingstudied will be collected by the primary mirror and

reflected to a 10-centimeter (3.9-inch) secondary mirror atthe far end of the telescope cylinder. The light energyis then directed into the spectrometer, where a complexoptical and electronic analysis occurs.- more -


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E N T R A N C ES L I T S

CONCAVEGRATING

C A S S E G R A I NS E C O N D A R YM I R R O R

tFINE CONTROLGUIDANCE OPTICS

P H O T O M U L T I P L I E RROTATING MIRRORSECOND F I E L D L E N SR O O F P R I S MFIR ST F I E L D L E N SZ E R O - O R D E RL O W - R E S O L U T I O NS C A N P H O T O M U L T I P L I E RHIGH-RESOLUTIONSCAN P H O T O M U L T I P L I E RROWLAND C I R C L ESCANNINGC A R R I A G E SP R I M A R YM I R R O R

E N T R A N C ES LI TS

P H O T O M U L T I P L I E R SS P E C T R O G R A P HS T RUC T URE

VIEW B - B

Princeton Experiment Optical Layout


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The en d product is a series of photon counts that areproportion al to t he inten sity of light of s pec ific wave-len gths. These data are then telemet ered t o ground stationsand recorded for later analysis.

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- 1 1 -THE X-RAY EXPERIMENT

The University College London X-ray experiment isthe first non-U.S. experiment carried by an OAO. Itspurpose is to study stellar X-ray sources and X-ray absorp-tion in interstellar space.

The experiment package, mounted in an upper bay ofthe main body of the observatory, consists of three smalltelescopes to study X-rays at wavelengths up to 70 Angstroms.The telescopes are supplemented by a collimated proportionalcounter covering the range of one to three Angstroms.This device views a larger portion of the sky background.

Detection and analysis of X-ray data involves gasproportional counters and an open tube channel multiplier.Data obtained will be relayed to ground stations,where it will be recorded and sent to the UniversityCollege of London. The experiment will use about 10 percent of the observatory viewing time.

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E L E C T R O N I C S

S T R U C T U R A LF R A M E

E L E C T R O N I C S

H E A T S H I E L D( A P E R T U R E M A S K )

R E F L E C T O R S

A P E R T U R EM E C H A N I S M SD ETECTO RS

University College London ExperimentStellar X-Ray Telescope


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GUEST INVESTIGATOR PROGRAM

To broaden participation of the scientific communityin the OAO program, a guest investigator program wasestablished with the OAO 2. Initially 14 proposals wereselected by NASA and a list of 107 objects approved.During its first three years of operation the programhas provided almost 500 observations. In addition to formalOAO guest investigators, a large number of scientistsparticipated in the program on an informal.basis. Thisprogram has been highly successful. !

When data from OAO-C become available, guest investi-gators will be appointed by NASA on the basis of jointproposals submitted with the principal investigator.Guest investigators will then work directly with principalinvestigators to obtain the data they need. The program isopen to both U.S. and foreign astronomers. N

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OAO 2 SCIENTIFIC RESULTS

OAO 2 has operated successfully for more than threeand one-half years. In doing so it has far exceeded it sengineering an d scientific objectives. It s design life-time of o n e year has been exceeded because o f outstandingefforts by engineers and technicians at the OAO OperationsControl Center, Goddard Space Flight Center, and at thefive tracking stations collecting its scientific data.

To date, OAO 2 has obtained data on more than 3,000star fields containing more than 25,000 stars. It hasmade over 10,000 individual observations of about 1,500celestial objects.The first major scientific results from OAO 2 were

reported in 41 papers at a special meeting of the AmericanAstronomical Society at Amherst, Mass., last year. Thepapers summarized the work of 45 investigators who repre-s e n t ed 21 different institutions. A comprehensive article,"Orbiting Astronomical Observatory: Review of ScientificResults," appears in the July 21, 1972, issue of Sciencejournal.OAO 2 has discovered that the intensity of radiationin extragalactic-nebula (outside of our own galaxy)increases in the far ultraviolet. The excess energy isprobably due to the light from the hottest young stars,but the rise of intensity in the ultraviolet is t oo steepto be attributed to the stars alone. A likely theory isthat dust within the galaxy reshapes this energy curve.If this interpretation is right, it may also explain thestrong infrared radiation recently observed from galaxies.The ultraviolet excess is of importance fo r several aspects

of extragalactic research:* fo r determining the dust content of galaxies;* for determining the stellar content and stellarevolution processes in galaxies;* for correcting ground-based observations for theeffect of the red shift; an d* fo r comparing cosmological theories with observations,


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OAO 2 also discovered magnesium emission in the spectraof cool giant and supergiant stars. Magnesium emissionis an indicator of activity in the chromospheres (outeratmospheres) of the sun and stars. Detailed spectralobservations of stellar magnesium gives valuable data onthe existence and nature of stellar chromospheres undera wide range of temperatures and gravity. Not only dosuch observations provide greater insight into the natureof stellar chromospheres, but they also test theories ofthe solar chromosphere in ways not now possible.

Other OAO 2 findings include:* Study of the absorption and scattering of starlightin the upper atmosphere of Earth that has providedadditional information on the structure and composi-tion of the upper atmosphere.* Discovery of a huge hydrogen cloud a million milesin diameter around comet Tago-Sato-Kosaka.* Observations that may settle a long standing enigmaconcerning a group of stars notable for apparentlyanomalous elemental abundances and for their enormousmagnetic fields, more than 10,000 times strongerthan our sun's.Discovery that hottest stars are even hotter thansuspected, are.aging about twice as fast as suspected,and are burning hydrogen at a very rapid rate.

* Observations in May this year of a supernova ; thefirst to be viewed by satellite in the smallgalaxy NGC 5253. This is the brightest supernovain the past 35 years; for a short time its ultra-violet intensity out shone the entire galaxy towhich it belongs.

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ATLAS-CENTAUR LAUNCH VEHICLE

OAO-C is the 21st operational launch for the Atlas-Centaur. So far during 1972 it has successfully launchedtwo Intelsat IV commercial communications satellites intoEarth orbit and a Pioneer spacecraft to fly-by Jupiterand eventually out of the solar system.

The Atlas booster develops 1,793,350 newtons (403,000pounds) of thrust at liftoff using two 760,950-newton (171,000-pound) thrust booster engines and one 267,000-newton (60,000-pound) thrust sustainer engine. Its propellants are RP-1(a kerosene type fuel) and liquid oxygen (LOX).The Centaur second stage, which was developed and is

flown under the direction of NASA, Lewis Research Center,Cleveland, Ohio, was the first U.S. rocket to use the highenergy liquid hydrogen, liquid oxygen combination. Itstwo RL-10 engines develop 66,750 newtons (15,000 pounds)thrust each. Flown in combination with the Atlas boosterup to the present time, Centaur is in the process of beingintegrated with the Titan III booster to launch Vikingspacecraft to Mars in 1975 and other large payloads.Centaur carries insulation panels and a nose fairingwhich are jettisoned after the vehicle leaves theEarth's atmosphere. The insulation panels, weighing about522 kg. (1,150 Ibs.), surround the second stage propellanttanks to prevent the heat of air friction from causingexcessive boil-off of liquid hydrogen during flight throughthe atmosphere. The nose fairing protects the payloadfrom the same heat environment.The only changes in launch vehicle hardware comparedwith the last OAO launched by Atlas-Centaur is the insta.lla-tion of an auxiliary spring system on the nose fairing.The OAO-B mission which was launched on an Atlas-Centaurin the fall of 1970 failed when the shroud did not completely

separate. On subsequent flights of Centaur a new type ofexplosive bolt w,-as used and no further failures have occurred.Now qualification tests have been completed on a new auxiliaryspring system to give added insurance that the two halvesof the nose fairing will completely separate from eachother during flight.

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Launch Vehicle CharacteristicsLiftoff weight including spacecraft;

Liftoff height:

Launcn complex:Launch Azimuth:

Weight:

Height:

Thrust:

PropelIants

Propulsion:

Velocity:

Guidance:

AtlasBooster128,547 kg(283,393 Ibs.)21.3 meters(70 feet)

1,793,350 Newtons(403,000 Ibs.)(sea level)Liquid Oxygen &RP-1

149,012 kg(328,510 Ibs.)41.2 meters(135 feet 4 inches)36 B60 degreesCentaur Stage18,247 kg(40,227 Ibs.)19.9 meters(65 feet, 4 inches)(with payload fairing)133,500 Newtons(30,000 Ibs.)(vacuum)Liquid hydrogen &liquid oxygen

MA-5 system (2- Two 67,000-N760,950-Newton (15,000-lb.) thrust171,000 Ib.) thrust RL-10 engines,engines, 1-267,000 N 14 small hydrogen(60,000 Ib.) sustainer peroxide thrustersengine and 2-2,982-N(670-lb.) thrustvernier engines.)8,709 meters perhour (5,443 mph) atBECO; 10,634 metersper hour (6,646 mph)at SECO.Pre-programmed auto-pilot through BECO.Switch to Centaurinertial guidance forsustainer phase.

25,259 meters perhour (15,787 mph)at spacecraftseparationInertial guidance.

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FLIGHT SEQUENCE

Atlas PhaseAfter liftoff, AC-22 will rise vertically for about15 seconds before beginning its pitch program. Beginningat two seconds after liftoff and continuing until T plus20 seconds, the vehicle will roll to the desired flightazimuth of 60 degrees.After 151 seconds of flight, the booster engines areshut down (BECO) and jettisoned three seconds later. TheCentaur guidance system then takes over flight control.The Atlas sustainer engine continues to propel the vehicle

to an altitude of 221 kilometers (138 statue miles). Priorto sustainer engine shutdown, the second stage insulationpanels are jettisoned.The Atlas and Centaur stages are then separated by anexplosive shaped charge that slices through the interstageadapter. Retro-rockets mounted on the Atlas slow the spentAtlas stage.

Centaur PhaseAt approximately four minutes four seconds into the flight,

the Centaur's two RL-10 engines are ignited for about sevenand one-half minutes. This will place the Centaur and OAOspacecraft in a near circular orbit at an altitude of 740kilometers (460 statute miles) .Twelve seconds after main engine start, the nose fairingaround the spacecraft is separated. Twenty five seconds aftermain engine start, Centaur initiates a right yaw maneuver toattain the final orbital inclination of 35 degrees. Theorginal launch azimuth of 60 degrees was designed to avoidthe Bermuda area during re-entry of the Atla's booster andnose fairing.

SeparationSeparation of the OAO spacecraft takes place by firingexplosive bolts on a V-shaped metal band holding the space-craft to the adapter. Compressed springs then push thespacecraft away from the launch vehicle at a rate of aboutone meter (3.2 feet) per second.

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OAO-C ORBITAL OPERATIONS

Once in orbit the observatory will undergo an extensivecheck out from the ground to assure that all systems areoperating as planned.

The first 12 hours in the life of the newly designatedCopernicus spacecraftis called the survival phase. Duringthis critical time a minimum expenditure of control gas willoccur. Efforts will be made to confirm that the observatoryis stabilized and that basic systems are in proper order.With orbit 16, the stabilization systems checks willbegin. On orbit 20 the spacecraft will be reoriented and,beginning with orbit 26, star tracker high voltage systems willbe turned on and checked. If the trackers are ready, star

search will begin during orbit 28.By day four, during orbit 56, plans call for checkoutof the University College, London X-ray experiment. Then,on orbit 57, the Princeton Experiment Package low voltage

turn-on is scheduled, with high-voltage turn-on during orbit59.Experiment checkouts will continue until orbit 98. Thena series of spacecraft checks will be undertaken until orbit115, at which time formal experimentation begins.The entire checkoutone of the most thorough ever under-taken w'ith an unmanned spacecraftwill be completed about12 days after orbit is achieved. Copernicus will then beoperational.

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THE OAO-C TEAM

NASA Headquarters

Dr. John E. Naugle

Vincent L. Johnson

Jesse L. Mitchell

C. Dixon AshworthHubert D. CalahanDr. Nancy G. RomanJoseph B. Mahon

T. Bland Norris

F. Robert Schmidt

Goddard Space Flight CenterDr. John F. ClarkRobert N. LindleyJoseph PurcellDr. James E. Kupperian, Jr.

Robert W. StroupNorman L. MartinLouis A. Koschmeder

Associate Administratorfor Space ScienceDeputy Associate Administratorfor Space ScienceDirector of Physics andAstronomy ProgramsOAO Program ManagerOAO Program EngineerOAO Program ScientistDirector of Launch Vehicleand Propulsion ProgramManager, Medium LaunchVehiclesAtlas-Centaur ProgramManager

DirectorDirector of ProjectsProject ManagerDeputy Project Manager/Project Scientist

Assistant Project ManagerProject CoordinatorMission Operations Manager


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GSFC cont'dRobert L. SchlechterJack SargentWilliam A. WhiteAdolph J. Cervenka

Sabastain N. CostaStephen F. O'Dea

Kennedy Space CenterDr. Kurt H. DebusJohn J. Neilon

John Gossett

Lewis Research CenterBruce T. LundinEdmund R. JonashW. R. Dunbar

Daniel J. Shramo

Lawrence J. Ross

Princeton UniversityProfessor Lyman Spitzer, Jr.Professor John E. Rogerson, Jr,

Integration and Test ManagerObservatory System ManagerExperiments System ManagerMission Analysis and PlansManagerMission Support ManagerNetwork Support Manager

DirectorDirector, Unmanned LaunchOperationsManager, Centaur LaunchOperations

DirectorDirector, Launch VehiclesDeputy Director, LaunchVehiclesAtlas-Centaur ProjectManagerProject Engineer

Principal InvestigatorExecutive Director, OAO Program

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Major Spacecraft Subcontractors

CompanyAdcole Corp.Waltham, Mass.ArcoGreat Neck, New YorkAVCO Corp.Electronics DivisionCincinnati, OhioBendix CorporationElectric Power DivisionEatontown, N.J.Bendix CorporationClips-Pioneer DivisionTeterboro, N.J.Dalmo Victor Co.Belmont, CalifGranger AssociatesBohemia, N.Y.Fairchild IndustriesSpace and Electronic SystemsDivisionGermantown, Md.General Electric Co.Spacecraft DepartmentValley Forge, Pa.Gulton IndustriesAlkaline Battery DivisionMetuchen, N. J.Hughes Aircraft Co.Culver City, Calif.IBMFederal Systems DivisionOwego, N. Y.

Responsibility

Solar aspect sensors

Electrical componentsOAO command receiver

OAO power control unit,power regulator unit, anddiode boxFixed head tracker

Magnetic unloading system

Diplexer and hybrid junction

Thermal control louvers

Stabilization and ControlSystem

Storage battery

Solid state transmitters

Primary processor and datastorage programmer and slsartracker sequence controller andspacecraft system controllerunit equipment


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ITT Federal LaboratoriesSan Fernando, Calif.Kollsman Instrument Corp.Syosset, N. Y.Magnetic Control CompanyADC-Product DivisonMinneapolisRadiation Corp.Melbourne, Fla.

Spectro-LabSylmar, Calif.

Boresight star tracker

Gimbal star trackersCurrent sensors (OAO)

Spacecraft data handlingequipment/Experimentersdata handling equipment.Solar arrays


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OAO-C FACT SHEET

SpacecraftWeight:

Structure:

Stabilization andControl:

Experiments;Princeton ExperimentPackage (PEP):

2,200 kilograms (4,900 pounds),including 450 kilograms (1,000pounds) of scientific experiments.Eight-sided cylinder, 2.1 meters(seven feet) wide; 3.0 meters long(10 feet). Overall width is 6.3meters (21 feet) with solar panelsextended.Three-axis stabilized, with pointingaccuracy of .1 arc secondmostprecise ever achieved by a space-craft. System uses four gimbaledstar trackers, an inertial referenceunit (IRU) to facilitate slewmaneuvers and maintain pointingaccuracy, and a system of stabilizinggyros.

Located in central experiment tubeof spacecraft. PEP is a 3-meter(10 feet) long ultraviolet telescope,an 82-centimeter (32-inch) mirror,an ultraviolet spectrometer andsensors for the telescope guidancesystem, able to view stars as faintas the seventh magnitude.Scientific objectives includestudy of the abundance and temperaturedistribution of the interstellargas from which stars form; studythe structure of stellar atmospheresof young, hot stars. Data receivedin digital form.

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University College ofLondon X-Ray Package;

Launch:

Planned Orbit:

Operating Lifetime;Tracking and DataAcquisition;

OAO Project Management;

Atl s-Centaur Management:

Launch Operations;

OAO Prime Contractor:

Atlas-Centaur PrimeContractor:

Mounted in an upper bay of themain body of the spacecraft,experiment consists of three smalltelescopes and a collimated pro-portional counter. This X-rayexperiment will permit pinpointingmany of the recently-discovered X-raysources more precisely. Datareceived in digital form.On board a two-stage Atlas-Centaurrocket from Launch Complex 36,Kennedy Space Center, Fla.Circular, 740 kilometers (460statue miles), inclined 35 degrees.Orbital period is 100 minutes.One Year.Space Tracking Data Network (STDN)stations at Rosman, N.C.; Quito,Ecuador; Santiago, Chile, operatedby the Goddard Space Flight Center.Goddard Space Flight Center,Greenbelt, Md.Lewis Research Center, Cleveland,OhioUnmanned Launch Operations,Kennedy Space Center, Fla.Grumman Aerospace Corp.Bethpage, N.Y.General Dynamics-ConvairSan Diego, Calif.

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oao-c press kit

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