ogo-f press kit

8/8/2019 OGO-F Press kit

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NA TIO NA L AERONAUTICS AN D SPACE ADMINISTRATION WO 2-415WASHINGTON,D .C. 20546 TELS W O 3-692

FOR RELEASE: MONDAY P.M.June 2, 1969REIlEASE NO: 69-81

PROJECT:.(To be launched noeaPller thanJune 5, 1969)

contents

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I. (CODE)/

(NASA CR OR TUX O R AD NUMBER)'3 \

(CATEOORYJ

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NA TIO NA L AERONAUTICS A N D SPACE ADM INISTRATION W O 2-415N E W S WASHINGTON,D .C .20546 T E L S ' W O 3-69FOR RELEASE: MONDAY P.M.June 2, 1969

RELEASE NO: 69-81

FINAL OGO READIED FOR LAUNCH

The l a s t observatory of the Orbi t ing GeophysicalObservatory (OGO) Program, OGO-F, i s scheduled for launchi n t o a low a l t i tu de , near ly pola r o rb i t fzaom the WesternT e s t Range, Lompoc, C a l i f , , no e a r l i e r than June 5 , 1969.

The launch of OGO-F marks the f i n a l phase of an eraof large automated s a t e l l i t e s t u d i e s of t h e nature and v a r i -a b i l i t y of th e Ear th ' s near space environment under t h einfluence of the Sun.

Planned f o r t he period of maximum sunspot activity,the OW-F mission w i l l i n v e s t ig a t e the Earth 's upper atmospherand ionosphere, the auroral regions surrounding t h e poles,and the edges of the regions of t rapped r a d i a t i o n ,

P a r t i c u l a r emphasis w i l l be placed on the i n t e r r e l a t i o r i -sh i p s between par t i c l e ac t i v i ty , aurora and airglow, t h e geo-magnetic f i e l d , t h e neutral and ionized composition, wavepropagation and noise, and t h e input so la r energy contr ibut ingt o io n i z a t io n and heating.

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-2-The 25 experiments packed i n th e 1,393-pound

observatory-the heaviest of t h e OGO series-will obta inglobal data over a complete range of l a t i t u d e s extendingfrom t h e Equator t o t h e v i c i n i t y of t h e poles.ments were contributed by 10 domestic un iv er si ti es , oneforei gn unive rsi ty, fou r government related centers and f i v e

The experi-

private companies.I F successfu l ly orb i ted by a THORAD-Agena D launoh

rocket, OGO-F w i l l be designated 060-6.The OGO program was i n i t i a t e d i n 1960 t o undertake

th e dlvers i f i ed co rr el at iv e measurements required t o under-stand be t t e r Earth-Sun relat ionships and the near-Earthenvironment. The large, standardized three-axia s t ab il iz edobservatory conceived a t t h a t t i m e has, with minor modifications,accommodated the 130 experiments assigned t o t h e s i x OGOmissions.

The 000 s t a b i l i z a t i o n system f e a tu r e s a n a c t iv e three-axis# five-degrees-of-freedom system which poin ts t h e bottomportion of t h e main body always toward t h e Earth, t h e s o l a rpanels automatically toward the Sun, and rotating experimentpackages in th e direction of motion.

Booms mounted on t h e main body, which give OGOs t h e i rin se ct -l ik e appearance, c ar ry experiment packages which aresens i t ive t o spacec ra f t d i s tmbances , o r which require p a r t i -cular viewing directions.

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Thedesignedadvanced

-3-OGO Communications and Data Handling Systemi n t h e e a r l y 19601s a s a t that t i m e th e mostincorpora ted in to a sa te l l i t e , i n terms of data

ra te f l e x i b i l i t y and commandable c on tro l .The f i r s t OGO, launched I n September 1964, near t h e

period of minimum solar a c t i v i t y carried 20 experiments Intoa h igh ly e l l i p t i c a l o r b i t f o r s tu d ie s of the E a r t h ' s magnet-osphere. As a consequence o f a f a i l u r e - t o lock on Ear t h , 00-1entered a spin-stabilized mode. Four and one-half years l a t e r ,long beyond th e expected l i f e of i t s sytems, t h e OGO-1 missionis s t i l l providing useful data from about; ha l f of I t s experi-ments.

Two other missions, OGO-3 i n June 1966 and OGO-5 i nMarch 1968 wepe launched i n t o an o r b i t similar t o t h e OGO-1or bi t . Both observatories are t r ansmi t t ing ; OGO-3 i s sp ins t a b i l i z e d ami OGO-5 has performed w e l l i n the three-axisstabilized mode for over a year.

OGO-2, launched i n October 1965, was t h e f i r s t 000placed i n a low a l t i t u d e , near ly po la r o rb i t . The missionencountered problems w i t h Fhrth horizon sensing ear ly i n i t sl i f e but aontinued t o provide data for two years.launched i n August 1967, during t h e period of inc reas ing so la ra c ti v i t y performed w e l l for eighteen months. I n January 1969,

OGO-4

OGO-4 was placed i n a holding mode. After the OGO-F launch,t h e OGO-4 mission w i l l be r e -s t ab i li z ed f a r c o r r e l a t i v e i n t e r -s a t e l l i t e s t u d i e s.

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-4-e ~ ~ v e ~ o ~ ~ ~ n tf a large complex, bus-type,

space research, and t h emx, under strenuous conditions,

engineering achievement, Experi-enef i ted o the r space programs

and has provided hnologg base f o r t h e development ofoxy concepts,

l ~ ~ h r n ~ ~ t sf t h e 060 program haveact; on the understanding of E a r t h ' s space

e of these observatories andthe l a rg e comple ents making simultaneous measure-

so lu t ion aorrelative s t u d i e se ~ a t u ~ ~f t h i s environment,

than B,200,000 mill ion hours ofcqudred by the f i r s t f i v e OGO missions

~ n ~ ~ ~ g save been disseminated i np u ~ ~ i s ~ ~ ~eports , including 32 paperseeing of t h e American Geophysical

Union in Ma

a t i o n of protons responsible f o r ahe Ekrth a t a d is tance of severa l


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-5-e f i r s t at^^^ lobal survey of t h e Earth's

magnetic fie1 , r e s u l t i n a proposed new magnetic fieldmodel for the In te rna t fo tic efesence Field.

* Clear ~ ~ ~ ~ ~ i f i c a t i ~ ~f the controlling influenceof th e Earth's ~ ~ ~ n ~ ~ ~ ci e l d on i o n population.t i o n of the exkstence of 8n inward boundary,

t h e plasmapause, ~~~r~~~~~~~he region o f stable trappedr a ~ f a ~ ~ ~ ~ ,

* First evidence t ha t a T gian of l o w energy electronscompletely envelops the trapped radiation regions.

ht aurome.e m p of airglow d i s t r i b u t i o n ,

t h e Earkh s bow shackrf@ field measurements fn the bow

shock m

which cou3d oZar p a r t i c l e s g e t i n t o the rmgnet-

e c t i o t ~ f n -ducted propagatlan o f veryOW frequency waves

* F i r s t ~ b ~ ~ ~ ~ a t i o ~f enhancement of man-aade whlrs t lermode waves by mgne ospherfc focusing,


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The 000 resul ts are pointing the way to th e re sou l t ionof important quest ions i n energ eti c pa r t i c l e and wave propa-ga ti on physics, ionicplasma physi cs and photochemistry. Dataon t h e ionosphere and propagation mechanisms are expected tolead t o improvements i n long-range communications. Studiesof large soale plasma physics phenomena may h e l p to a c c e l e r a t elabo rato ry ef f o r t s directe d towards confinement of hot plasmas,

Understanding of th e chemistry of t h e Ear th ' s atmosphereprovides a basis fo r understanding th e environment of o the rplanetary atmospheres and wlll be an important feature i n t h efoumulation of t h e o r e t i c a l models explaining t h e formation andevolution of planekary environments.

I n o r b i t , O W esembles a g ia nt , s u r r e a l i s t i c I n s ec tbecause of th e many arm and leg-like booms, antennas, andwing-like so la r panels whlch J u t from its rectangular, box-shaped main body. With i t s booms aud solar pane ls fu l ly deployeda f t e r i n j ec t i o n i n t o o r b i t , OGO i s about 49 feet long and20.5 feet wide.each end of t h e s o l a r paddles, the width i s approximately60 feet . Each OGO has more than 100,000 separate parts.Duping launch, t h e 000 appendages are folded against the main

With f u l l y deployed experiment antennas a t

body


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-7-The O r b i t i n g Geophysical Observatory progxaarn is m r t

o f the NASA's scientif ic space exploration study conductedby the Office of Space Science and Applications, Washington,D,C, OGO project management is th e re sp sn sl bi l i ty of QoddardSpace F l i g h t Center, Greenbelt, Md,

NASA*s Lewis Research Canter, Cleveland, is re spons ib l efor the THOW/Ager?a launch rocket,performed by t h e A i r Force8s 6595th Aerospace Test Wing undert h e t echn ica l d i rec t ion o f NASA8sKennedy Space Center UnmannedLaunch Operations .

Launch operations are

OGO prime contrac tor is TRW Systems, Redondo Beach,C a l i f , The McDonnell Douglas ktrOnautiGf3 Co . , Santa Monica,Calif. developed th e TH0M.D and Lackheed Missiles and SpaaeCosp., Sunnyvale, Calif. produced the Agena stage. More than%OO,OOO subcontractors and vendors throughout the nat ion haveprovided various subayrst@msand electronics for t h e s a t e l l i t e .


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-8-OGO-F FACT SHEET

SPACECRAFT:S~pe.................................o~~~n body I s rec-tangular shape, s i x

f e e t long, t hree feetwide, three f ee t high;with appendages deployedspacecraf t looks l i k egiant i n s e c t , i s 49 feetlong and 20.5 feet wideO v e r a l l Weight.,...................4.D.l,393 poundsExperiment W@ight.................~....371 poundsAppendagea....,........................~~ 20-foot booms;four four-foot booms;

two solar panels , sixf e e t wide by e i g h t andone-half f ee t long withapgsoximatelyf ee t covered with33,000 N/P c e l l s ; t w oorbital planer experi-ment packages nominally18 by 9 by 10 inchesand 15 by 9 by 13 inche28-volt nickel cadmiumb a t t e r i e s u s i n g unreg-ulated direct currentwith maximum capabilityof about 560 watts,

power Supply.. ......................... Solar supply to t w oLAUNCH INFQREJIATION:

Vehicle. ............................. THORAD/Agena D

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NOMINAL OFZBITAL ELEMENTS:Apo~ee..........................~..~~.A~~~~ 680 s t a t u t e milesPerigee. ............................. .About 245 s t a t u t e miles~ n c l i n a t i o n . . . . . . . . . . . . . o . . . o . . . . . . . o o ~ 2 degrees progradeP e r l o d . . o . . . . . . . . . . . . . . . o . . . . o . . o . . . . ~ A b ~ u t 100 minutes.

TRACKING AND DATA A C Q U I S I T I O N STATIONS(STADAN) ill perform tracking, telemetry and data acqu is i t ionfunc t ions f o r QW-F, STADAN a t a t i o n s are located a t College,Alaska3 Fort Myersp Fla.; Newfoundland; Rosmn, N.C.; Winkfield,England; Q u i t o , Ecuador; Lima, Peru; Sarnklago, Chile; Johannes-burg, South Afriea, and Carnarvon and Orrora). Vglley, Austral ia .

The network 18 operated by th e Goddary Space Flight Center,Greenbelt, Md. F a c i l i t i e s are operated for ASA i n A u s t r a l i a bythe Australian Department of' Supply and 3-n the Republic of SouthAfrica by the South African Council f o r S 0 3 m W a B , $ i C and Industr ialResearch.

NASA's Spalse Tracking and Data A c Q ~ ~ ~ ~etwork

OBSERVATORY MBNAGEMIENT:............o..~.o.oOf~~~e of Space Scienceend Applications, NASAHeadquarters, and NASA*sGoddart3 Space F l i g h tCenter.LAUNCH 3ll3HICLE MANAGEMENT: ................NASA/Lewis Research

CenterLAUNCH OPERATIQNS:...................e..~.e~. 8. A i r Force 6595thAerospace Test W i n gu s d e ~ h e t echn ica lsupervision of' t h e NASAKennedy Space CenterUnmanned Launch Operat ions

QFU-I? S p a e e c r a f t . . . . . Q . . o . . . . . . . . ~ o ~ . . T ~ Wystems, RedondoBeach, C a l i f .

e..O.....~.............eao..Loekhe~d Missile andSpace Corp., Sunnyvale,C a l i f .-more-


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-10-06fO-F SPACECRAFT

OIW-F cons i s t s of a main body about six feet long, threef e e t deep and three feet wide. Attached t o t h i s s e c t io n a r e 12appendages.experiment instwmentation which must be mounted away from t h emain body t o avoid magnetic and ot he r di st ur bi ng ef fe ct s.

Four four-foot-long booms ca r ry somewhat less s e n s i t i v eexperiments, OQO antennas are mounted away from t h e main bodyt o take advantage of improved antenna pattern8 made poss ib leby *his technique,

Two 22-foot- long booms, l ong es t on t h e sa t e l l i t e , ca r ry

Other exter nal chamcater is t ics of t h e s a t e l l i t e Includet w o box-like packages which ca r ry experim ents and can be ro-tated so tha t the experlment packages can be aligned in t h eplane o f % he o rb i t .These packages, ca l led t h e OPEPs (Orbital Plane ExperimentPackages) are of d i f f e r e n t s izes , The l a r g e s t i s approximately18 Inshes long, 10 inches high and 9 inches deep.experiments which w i l l take readfngs i n the erblta3. plane of t h es a t e l l i t e .

They ca r ry

Also mounted externally are a t t i t u d e con t ro l j e t nozzleswhich are placed an booms a t one end of OGO. T h i s placementincreases t h e l e v e r arm action and h e l p s s t a b i l i z e t h e s a t e l l i t eand reduce gas system weight,

Two larger solar-cell panels convert s o l a r enesrgy i n t oe lec t r ica l power fo r s a t e l l i t e operation. The panels are mountedon a shaft runnjtng through the main body. They ro ta te au to -matically , as or ien ta t ion of the observ atory changes, t o permitthem t o f ac e the Sun continously,Two solar oriented experiment packages (SOEPs) are mountedon th e solar panels.to look toward the Sun.These paokages contain experiments designedExperiments not se ns it iv e t o the s a t e l l i t e ' s local environ-ment are mauni;ed on t h e Ins ide of two large hinged doors. Thodoors aan be opened fop access t o equipment o r experiments.

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Power Sub ysternThe 33,QOO s o l a r c e l l s mounted on the two solar arraysThis is stored i n two 12 ampere-hour nickel-cadmiumprovide about 560 watts of elec.t;ric power,batteries.A n average of 100 watts and a peak of 140 watts ofpower are reserved for experiments,

Att i tude Control SystemThe OGO-F a t t i t u d e control syseern fa designed t o keepthe rsatellite s t a b i l i z e d I n a l l three axes (pitch, yaw and r o l l ) ,

with in two degrees of local v e r t i c a l , w i t h f i v e degkees ofth e Sun, and one sltde orfented toward Ehrth. lChe O P E P s arethen or iented with in f i v e de re88 o f the o r b l t a l plane. Thiss t a b i l i z a t io n p ro vide s a platform for accura te direct ional mea-sum?ernents.Basically , the o s n t ro l system c o n s i s t s of horizon scannerszSun sensors, servssl gas jees, elec tr ica l ly-dr iven flywheelsand associated elee tranlcs .Horizon scanners sense the in f rared edge of %he B r t hand provide erpox. signals ts t h e inertla1 flywheels and gas jetswhich force the s a t e l l i t e t o t u rn about In t h e r o l l and p i t c haxes i n s u r l ng that t h e bottom of the main body always po in tstowards Eareh.Error sggnals for contro l l ing yaw motion, and s0tatfOnof the power-producing s o l a r pan els , are contro l led by Sun sen-so rs s i tua ted on t h e ends of the panels,The body yaw torque, roduced by another in e r t i a wheeland a set of gas j e t s , keeps th e axis of the solar panels normaland the plane of the main body thermal radiat ion louvers parallelt o the S u n l i n e ,A third por t ion of the system controls the OPEPs topennit some of the experiments to look along the p a t h of t h esate l l i te .These experiments are directed forward in th e plane of theO P b i t and n0-1 to &he o b S e ~ a t O r y - E a P t hline. OPEPS can alsoscan across t;he orbltal plane on B d.


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The QPEP sensor is a gyroscope operatad i n a gyrocompassmode. Its e r r o r voltage contro ls a dri ve which r ot at es t h eOPEPS W2th ??6?8peCt t o t h e body,Them1 Contra1 System

A combination active and passive t h e m 1 c o n t m l systemregulates temperatures i n the electronics syrstm cof the observatory.body are kept between about 41 t o 95 degrees F. by sets o fradiating panels and 101 temperature-actuated alurn?lnum l o u v e r slocated on three sides of $he main body,

The temperatures of all assemblies w i t h l a the main

The temperalures of appendage packages ~ o ~experPment instruments are contro l led by a similar thermalbalance technique, exoept that; louvers are not used, 6heaters are used t o maintain temperature l l m i t s when "ce observa-tory 2s i n eclipse o r when experiments are turned off,

This system i s designed t o keep the at^the appendage csnt;ainsrs within the range of about 32 to 104degrees F,Comunioations and Data Handlfng

The QGQ comunications and data handling sysbena 3.9designed to provide for tracking and c a r a d f u n c t i o n s bothdata for 20 t o 30 separate experiments,tion) system using a nine-bi& word and cap ble oA' operatinga t three data rates which ape se lec ted by ground CQWIEUI~,

The realtime data rate capab i l i ty sf the OW-E' systemranges from 8,000 tc 64,000 blts-pes-second,t w o tape recorders a t 8,OQo bits-per-second p l ay back at 128,000bits-per-second.

f o r satel3bite hOus6kt?epirlg and @Tperimti%lt op6?lqatiQnand %elemeli;ryThe maPn telemetry i s a wide-band PCM (pulse code modula-

Da%astored in

wte w i t h outputs t ransmitted t o Earth In real-ected t o one of the t w o tape recorders providedo three hours OP 86,000,000 bits of data, Thesedarta are t ransmitted by four-watt wide-b nd eransrnitters a t400 mhz,-more-


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-13-A special purpose tslmetry sy8%em9 capable of operatingfrom an experiment whossignal. varying frwr up t;o f i v e skandam! subcarrier oscillators,

includes the %ranambssicnof the ou%p~--cf ehhe ufde-band tele-metry system, spec ial purpose tmaartatltter is rated at 0.5wat;ts at 400 mtaz,

tput is an FR (Yrequency Modulated)For back-up, a aecond made of" i % - 5 -c;ccial purpose system

Data Procase3.wData received on magnetic tape by the world-wide networkof Tracking and Data Acquisition SteltiOi'm (STADAN) will beforwarded to the Gadda Space Flight Center.Tracking data ~ e n t o Goddiwd will be used for computationo f an accurate orb%$for EucperinaenCersa data analysis and forspacecraf.1; operalAarnEs,Taped data will be ~~~~~~~~d by high-lspeed computers,men the p r s c e s s l ~ h ~ ompleted, d i g i t a l computer tapes willbe produced f o r each ~ x ~ ~ ~ i ~ e n t ~ r .These tapes w i l l contain data %rsm each individual experi-ment, necessary tfmfng information, 8s well as daea on space-craft temperatures, v ~ ~ ~ ~ ~nd orbital data =- the standardhouseleeping hfOl%lakhnThe production data proces ng conducted a$ Goddardw f l l be basical ly a. ecztnpater sa bng operat ion, providing experi-mentera wi&h raw data from their experiments, Following thenecessary analysis and evaluation by expe~imeitnters,data f o rthe scien4;i f ic 60 niGy ~11311 e published In hscientific journals.The data ~83.3.al so be submitted to the National Spacet;a Center at Qoddard Space F l i g h t Center for t h e u s eof other Pnteresked sc i en t i s t s ,


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-14-000-F SCIENTIFIC OBJECTIVES AND EXPERIMENTS

The 371 pounds of instrumentation for the 25 experimentsof the WO-F mission cover the broad spectrum of th e space sciencedisciplines, and are correlative investigations I n rsolar, bePonay,energetic particle, auroral and ai.rglow physics,

The Information collected by these V 8 P i O U s experimentsshould help In understanding batter the Earth's environmentand the time-dependent relationship that exists in galactic,interplanetary and planetary events, wi2;h emphasltr on solar-terrestrial interactions,A t thd present time in space exploration, scientistsknow how t o make of 6h8 lmdividual-measurements of themagnetic f i e l d , particle f lux, ionization, etc,

the Interrelations between these qu6lntitlee and the @stablash-ment of detalled cause-and-effect relationships,The Important question facing space sclantists concernsAn eXatftpl@ I s the desire of physicisem t o study thedensity and composition of fhe upper atmosphere, and the waythe atmo8phere i s affected by radiation from the Sun and byenergetic particlea,To obtain this type of Information requires severalcoordinated experiments, and large data reduction systems (toturn the data Into easy-to-understand language) which leadsto the requirement of largescientific spacecraft in t h e OGOclass.Following are same o f the OGO-F near-Earthareas o finvestigation:#0

*e

**

Atmospheric and ionospheric measurementsAuroral and airglow studiesSolar radiation experimentsRadio emfssion measurementsMagnetic f i e l d measureaentsCosmic ray experiments


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OGO-F Experiment Locations

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These inves t iga t ions should he lp achieve some of t h efollowing objectivest* New knowledge OR th e la$itucjo and $fme-degendentv a r i a t i o n s o f $he pre88ure, temperature, dens i ty and ohem%s4?ryof the n m t m l atmosphere aurrounding the Earth;*emissions and $;heireffect on the Earth8s ionosphere, a tmaphereand airglow;me r e l a t i o n s h ip Between rPolar X-ray and u l t r a v i o l e t* FuI?ther fn8,ight into the p re c ip i t a t i o n o f e n e rg e t i cpart ic le8 and the in f lux of solar corrisic rays i n t o the auroraland polar regions and the occurenoe of aurora and po la r capblackout;* Measureneat; of solar u1t;rariofat and X-ray emissions* More information concerning low energy particles

d u r i n g a pefiiod of high a c t i v i t y ;trapped i n the Earth's magnetic field; tRe i n t e n s i t y of th emagnetic f i e l d , and the overa l l r e la t ionsh ip of the phenomewith very low frequency radio n o h e , ionospheric absonptionand solar a c t i v i t y ;field and f u r t h e r refinement of global magnetic field data a spart of t h e United Stxitest con t r ibu t ion to the World MagneticSurvey; and

* The d e f i n i t i o n of long- tern change5 i n th e geomagnetic

* A bet ter under nterplanetaryaching th e Eapace a8 revealed by cSun and from g a l a c t i c sources.

A t echn ica l desc r ip t ion of each of the OQO-F experifollows i n order t o he lp place i n oontext the types of instma-mentation used and the specifio areas tQ e s tudied by eachexperiment.Atmozrpheris and Ionospheric Stud ies

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!!!he primary objective of the experiment is t o measuret h e spa t ia l and temporal va ri at io ns i n t h e n e u t r a l a t ~ Q S p h e r i Cden sit y throughout the OW-F orb i t . Of par tPcu la r in teres t ; 1sl a t i t u d e v a ri a ti o n, day-night var ia t ions , and sofar a c t i v i t y -correlated v a r i a t i o n i n t h e atmospheric density.-more-


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A t h i n metallic ribbon, suspended between t h e polepieces of a permanent magnet, i s mounted i n t h e OPEP lookingalong the veloc i ty vector ,of the spacecraft. The atmosphericgas, having e f fec t ive ly the vel oci ty of th e vehicle , exerts apressure on t h i s ribbon which i s proportional to the atmosphericm a s density and the square of' t h e veloci ty of th e gas w i t hre spec t t o th e ribbon.Electron Temperature and Density (Univ, of Michigan, A n n Arbor,Mich,, - A. , Nagy, NASA/ OSPC - L. H. Brace)

This experiment will contribute t o a coordinatedof the aeronomy of' t h e upper atmosphere, It measure8electron temperature and density and i t also provideson the equi l ibr ium potent ia l of t h e spacecraft.studythe ambientinformation

The opera t ing pr inc ip le of t h e instrument i s thefollowing:sheath of' the spacecraft and the D.C. p o te n t i a l of the probei s varied a few v o l t s with respect to the spacecraft , The re-su l t ing co l lec ted cu rren t ve rsus app l ied V o l t a g e cha rac t e r i s t i c sare then used t o der ive e leo tron temperature and density andspacecraft potential . The experiment uses two Langmuir probesplaced on OPEP-2 a t 90 degrees t o each other, with one probelookine; in to the ve loc i ty vector . This arrangement I s h e l p f u li n evaluating axperlarentally the o r i e n t a t i o n e f f e c t s on t he v o l t -ampere c h a r a c t e r i s t i c s,

A small cyl indr ica l probe is placed outside t h e

C - C, A , Reber; Univ,The primary objec t ive of t h i s experiment i s t o s t u d ythe behavior of the aoncentrations of major constituents (N ,02, 0, He, and H ,) of the Ear th ' s neutral atmosphere dur ingvarying solar acg iv i ty and magnetic disturbances, and dur ingd i u r n a l , seasonal, and la t i tu di na l var ia t ion s , A secondaryobjec t ive i s t o obt ain aocura te measurements of t h e concentra-t i o n of t r ace cons t i tuen ts of the Earth's neu t ra l atmosphere,A quadrupole mass spectrometer i s used t o obtain theatmospheric composition data. The spectrometer system consistsof a quadrupole analyzer, i n which mass separation occurs w l t h -

i n a dc and a radio f requency e l ec t r ic f i e l d , an enoloaed d u a lfi la ment e l ec t ro n bombardment io n source, an e lec t ron mul t ip l ier ,suppor t ing e lec t ronics for operating the analyzer and soupee,and a break-off device f o r exposing t h e evacuated mass spectro-meter t o th e atmosphere once i n o rb it ,


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Atmospheric Ioa Concentration and Mass (NASA/GSFC - R.A. P i c k e t t lThe ob3ective of t h i s experiment i s t o study eheatmospheric t h e m 1 osit ive ion concentrat ion and mass i nThe instrument used i s a Bennett rf ion mass spectro-t h e range from 1 t o ! 5 atomic mass units (W ) ,meter oriented In t h e orbst plane and located in OPEP 2 , Thes p e c t rm e te r c o n s i s t s of 8 Cube with a series of plane-parallelk n i t t e d g r i d s mounted normal t o th e axis of the tube, A-C andD-6 f i e l d s acce le ra te the ions down the length of the tubetoward a col lec tor . To reach the c o l l e c t o r t h e ions m u s t passthrough a re ta rd ing po ten t ia l , Only those i o n s s a t i s fy in g t h eveloc ity and phase condftions established by t h e f i e l d s w i l lrece ive su ff ic ie n t energy from the f ie ld6 t o pass t h e re tardingpo ten t ia l and impinge on the oolleetor,

Ion Mass Spectrmeter (Southwset Center f o r Advanced Stud ie s ,hallas, Texas, - W. . Hanson)The objec t ive of t h i s experiment is t o provide measurementsof th e ambient ion oomposition along the spacec ra f t ' s o rb i ta lpath f o r those pos i t ive ly thawed ion8 i n the range from 1 t o 40

BMU.The instrument conslsts of' a 90 degree sector magneticanalyzer, an electron m u l t ip l i e r de.t;eotor and a l inear au tomat icranging electrometer located i n OPEP-1. The system is capableof measuring ion ooncentrations of th e order of 10 Ions per aubic

centimeter.Ionolsphere Ducting (SWAS - W, B. Hansonr

This experiment measures ion concentrations and tempera-tures throughout the Octo-F o r b i t i n order t o p rovide an under-standing of atmospheric chemistry and heating phenomena i n t h eupper atmosphere,of t h e lonosonde pulses from topside sounders along magneticf i e l d l i n e s are bel ieved t o be caused by f i e ld a l i g n e d i r r egu-l a r i t i e e i n t h e elec tron (Ion) concentrations, The experimentalso provides high resolution measu;rernent of horizontal ionconcentrat ion gradtents (ducts) with a s e n s i t i v i t y of one p a r tper thousand i n ion concentration and 300 meters i n spat ia l reso-lu t ion ,

The phenomena of whist ler ducting and ducting


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measwe ion tepapet ies i n ionn t i r e exper l y z e r andt r o n i c a mo e In OPEP-1,Energy Trmafer Probe (Faraday Laboratories, La Jolla, C a l i f , , -b. McKeown)

mt3 Pthe energylow atomic weight metals,v a r i a t i o n s In upper akaoephere densi ty by monitoring variationsi n the kinetic-energy f lux,'phe Instrument cronsistrs of four energy t ransfer probeslocated i n OFEP-1, A shu t t e r l a positioned i n f ro n t of theprobes .t;o chop the upper 8 % t m O r S p h e r i C stream, Each probe employs

B temperature-aensitlve quartz crystal t o detect energy transfer .The frequency inc se of a probe, during the period when theshutter 1s open, propo rtio +l t o the energy t ransferred to thecrystal sensor. Of t h e four probes, two are used t o measurethe accommodation eo-officlenta of gold and aluminum, one measuresthe k i n e t i c energy f l u x of th e upper atmoepheric stream and onei s used a s a control ,

ob jeo t lvs of this experiment l a t oodatlon and drag c o e f f i c i e n t s forA secondary obJective is t o determine

Solar X- r a y Einiusions (U. S, Naval Research Laboratory, Washington,b,C,, - M r . R. , Kreplin)'Measuring the s o l a r X-ray energy input t o the Earth andi t s v a r i a t i o n s i n order t o understand the geophysical parametersof the upper atmosphere is th e ob jec t ive of %hisexperiment;.Changes i n the solar radiation is on8 of the prlmary environ-mental inf 'luenaes aff ee tl ng th e ionoaphere, I n par t ic ul ar , so la rX-ray burs t s accompanying flares and a c t i v e rominences are thedirect; cause of increased D region ionizatl which In turni s responsible for ra di o fadeout, sudden croemia noise absorption(SCNA), and other manifestations of the sudden ionospheric dls-turbance ( S I D ) event, By establishing a Set of X-ray ind icesof solar a c t i v i t y , c o r r e l a t i o n w i t h other geophysical phenomena

can be made. The t i m e v a r i a t i o n of X-ray emissions playanImportant role i n the fonn@tion and v a r i a t i o n s in the D and Eregions of the ionosphere and appear to c o n s t i t u t e t h e predominents t rong ly variable component of solar rad ia t ion reaching the lowerionosphere,


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The inatnam4?ntatlon consllsts oftrwo de tec to rs , a proportionalcoun te r fo r the 2 t o 20 Kev range and a scIntlllator/photomul-t l p l l t t r f o r the 20 t o 150 Kev range. The detectors are locatedI n SOEP-1.

The ob jec t ive o f t h i s experiment I s t o monitor rad ia t ionl n t e n sl t l a s i n the extrents u l t r av io le t (160..ngprtrom degrees t c1600 angstrom degrees) portion of the solar spectrum.provide needed Information on lntxmsity levela and th e temporalv a r i a t l o n e of' these l e v e l s f o r c o r r e l a t i v e s u t i d e s of W emissionswith ionoapherlc and ataro8pheric phenomena,apectrorrretera located i nrange from 160 t o 1600A with an s f f e a t l v e o v e r a ll resolvingpower of 100. The s i x spectrometers cover independent bu t over-lapping s p e c t r a l rangeso t o give redundancy everywhere but a tthe sp ec tr al extremes. The wavelength scan i s qarr ied out in513 steps which covers t h e e n t i r e s p e c tr a l range. The experi-ment can also be commanded t o any of 15 short scans of 65 stepseach. A n aspect; system associated w1t;h *he experiment y i e l d sa measure of any departure made by the experiment axis from themean s o l a r vector.

It will

The i net rum ent c o n s l s t ~ f 6 collimator-plane grating80EP-2 which s8an the wavelength

Sola r Ul t rav io le t Survey (Univ, of Mew Mexico, Albuquerque,w. M., - Yo H. Reg:ener)-The ob jec t ive of th i s experiment I s t o provide longobservations of the ln tens&ty of solar r a d i a t i o n i n the ultra-v io le t r eg ion of the spectrum over the wavelength from 1850 t o3500 angstrams. So lar rad lat fon a t these wavelenga;hs i s l a rge l yresponsib le for th e dlaeocia t i on of oxygen In t h e upper atmosphere,for t h e existence and the v e s t l c a l d i s t r i b u t i o n of atmosphericozones, and f o r t h e t empera tu re d i s t r ibu t i on i n the upper atmos-phere.The experiment use8 a quart8 pr ism spectrograph mountedin SOEP-1 which i a programmed t o scan the u l t r a v i o l e t spectrum

ine ight ranges, moat of th approx.imately 300 angstroms wide. I naddi t ion , there ape two ra es in ehe v is i b l e spectrum, one affectedby ozone abso rpti bn i n t h e yellow-orange region, the o t h e r i ne range from 3560 t o !jOQO angstroms, where ozone does not absorb.e simul@aneougmonit;orfng of t h e v i s i b l e r a d ia t i o n i s intendedtozainly as a check on the equipment,

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Airglow and Auroral Studies

The primary purpose of t h e experiment i s t o s t u d y th eemitt ing regions a t 6300 angstroms (the red l i n e of atomicoxygen) and a t 3914 angstroms (0-0 band of he f i r s t negativet e m of nitrog , N2+) during airglow a auroral phenomena.Photometric measurements of th e 6300 angstrom ai rglo wa l t i t u d e d i s t r i bu t i o n w i l l provide in fomat ion f o r s tud iesof d i s s o c i a t i o n of 0 by so l a r u l t ra v io le t r ad ia t ions , d i s soc ia-t i v e recornbination of ions w i t h electroms i n t h e ionosphereand d irec t exci ta t ion of 0 by thermal electrorrs, In te r fe ro -met ric measurements i n t h e same band w i l l provide t h e shapeand wid th of t h i s l i n e fo r s tudy of tempera ture d i s t r i but i on .Observations of the 3914angstrom airgl ow w i l l provide data

on resonance radiation by N2+ and Ioniz atio n and exci tat ionof Ne by s o l a r X-rays.Observations during aurorae w i l l provide informationon e x c i t a t i o n mechanisms such as: energetic particle dumping,dissociat ive recombination w i t h electrons, fas t roton col-l i s ions , and optical resonances (sunlight AuroraP,

toward Ear th , The 3914 angstrom region of the spectrum i sobserved by using a second interference f i l t e r which auto-m a ti c al ly a l t e r n a t e s w i t h the 6300 angstrom interference f i l t e ri n f r o nt of th e photometer. A s t e p p i n g mirror provides a 32degree scan from the observatory horizontal plane.

The Fabry-Perot interferometer i s mounted I n t h e space-craft main body and looks out t h e spacecraft s ide panel,moving plane mirror permits the instrument t o scan t h e de-s i red emission region. With var ia t ion i n spacec raf t a l t i t u d eth e angular pos i t i on of t h e mirror 1s al tered through u s e ofsig nal s from t h e spacecraft horizon sensors.Ultraviolet Photometer (U, of Colorado, Boulder, Colo, -C. A , Barth; Packard B e l l - E, F, m c k e y )di s t r i bu t i on and temporal va r ia t ions of the i n t e n s i t y anddensity of atomic hydrogen (1216 angstroms) and oxygen (1304angstroms) i n airglow, i n t h e ou te r atmosphere of the Ear th ;and i n proton and el ect ron excited aurora.

The photometer i s mounted on a short boom and views

A

The purpose of t h i s experiment i a a study of th e spatial

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The instrumentation consists of a two-channel photo-meter designed t o measure ultraviolet radiation between 1100and 2500 angstrom.), Bnth channels h&vs l i t hiu m f lu o r id e f i l t e r sw i t h a band paaa of ?..sJ,CO t 0 2 5OO angbxtrm8 Imorpora ted wlthinth e P# tube. One pl?.dmmterchannel used this way, t h e &her.has a calcium f I u w B J d , e i l t e r plaa&rd %ween the l i th ium f l u -or ide window ar,d th e cohm mted aper%[email protected] a t t e r i s 1250 ea 2500 angstroms, Thus, t;he 1100 t o 2500 angstromand 1250 t o 2500 angstrom regions are measured simultaneously.photomultiplier8 look along the Ekr.t;h rad ius vec to r in ad i r e c t i o n away from t h e Earth. The PPI t u b e s are protectedfrom extended periods of' d i rec t sun l igh t B y a ground controlleddoor.

The band pass of t h e

The photometer is mounted on the observatory so t h a t t h e

The objective of th e experiment is a study of t h e zeni tha n g le d i s t r i b u t io r of Lyman-Alpha ra d i a t io n on a global basis.The primary S ~ u r c e f rad ia t ion 1s t h e Sun, and th e d i s t r i b u t i o noccurs by resonant scar;tering from t h e neutral hydrogen geocorona.From such measurements, the den s it y varIatzLon and ext en t of thehydrogen atmosphere labag be deduced. Ie may be poss ib le t o ob taininformation regad:l.nT the hydrogen temperature and t o observein terp lanetary raeu t r z l hydrogen.The instrurnentEQion ueed i s a 3 angstrom bandwidthphotometer a t 3.216 angstroms w i t h 8 f i v e degree f i e l d of view.The photometer 18 ovnteC exteunally 09 the top s ide of t h e

observatory, A P at ing 45 degree mirror makes a c i r c u l a rscan of th e sky above t h e observatory once each o r b i t . Theinstrument con tai ns an atomic hydrogen absor ption c e l l foranalys is of t h e r a d i a t i o n d i s t r i b u t io n ve r y close t o resonance.Three dif feren@absorpt ion prof i les are employed.

The ob jec t ive o f t h i s experiment i s t o measure thev a r i a t i o n of t h e absolute bltrightness of t h e Sodium D l i n e s(5890 angstroms and 5896 angstroms) and th e atomic oxygengreen l ine (5577 angstroms) during t h e day, t w i l i g h t and nightairglows.th e sodium layer should elucidate many problems re la ted t odus t in fl ux , sporadic-E, noc til uce nt clouds, atmospheric air-culation, and atmpspheric chemistry.

Global measurements of t h e a l t i t u d e and th e content of

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The instrument i s a photometer w i t h a scann%ngmirror(s imilar t o t h e Airglow and Auroral Emission photometer) andviews out the s i d e of th e observatory main body.Low Energy Auroral Part ic les (NASA/GSPC -. D, S. Evans)

The objec t ive of t h i s experiment is t o measure w i t hhigh energy reaolution the spectrum of a u ro ra l p a r t i c l e sover the energy range 0.7 Kev t o 20 Kev and t o inv es ti ga tethe v a r i a t i o n s in down fl u x of these particles.The experiment uses e igh t channel electron m u l t i p l i e rp a r t i c l e detectors located on the end of a short boom.these provides background measurements whi le t he remaining sevend e te c t low energy charged particles. The experiment is or iented

80 as t o measure parkicles precip i ta ted a t high l a t i t u d e s . Fiveof th e seven ac t ive de tec tors measure charged part icles (e i the re lec t rons ox1 protons as selected by ground command) I n f e e denergy bande, The plate voltage on t h e other two detectorsl a slowly swept as as t o ob ta in a high resolution scan overt h e energy spectrum 0.7 Kev t o 20 Kev.To obtain high resslution energy spectra I n o r near th eauroral zone, data acquired by ehese detec tors are stored onan experimenter provided tape recorder.is through the Observatory Speclial Purpose Telemetry System,

One of

Tape recorder playback

me QbJectiW38Of t h i s erinient are (1) t o discover th emechanism by which electrons are precipitated into the atmospherea t values of' two and greater; (2) to understand t h e re la t ianah ipbetween parClePe precipitation and p a r t i c l e t r a p p i n g i n t h eouter radiat ion zone; (3) t o re la te the phenomenon of p a r t i c l ep re c ip i t a t i o n to th e s t ru c tu re of the magnetosphere, particu-l a r i l y w i t h t h e neutra l poin t on t h e day side and t h e extendedt a i l on the n igh t side; and (4) to c o r r e l a t e p a r t i c l e p r e c ip i -t a t i o n with other time-varying phenomena, such as l o c a l magneticand e lec t r ic f i e l d variations, large-scale geomagnetic distur-bances, and auro ra l d isp lays .

photomult ip l ie r e lec t ron de tec tors t o observe direc t ions andf l u x intensities i n t h e range 45 t o 1200 Kev. Five of the 6detectors are configured t o accep t a r r iv in g pa r t i c le s i n a +4degree cone; $he s i x t h is an omni-directional de te cto r, Theexperiment i s mounted on t h e end of a s h o r t boom.

The instrumentation consists of six s c i n t i l l a t o r

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-23-Trapped and Precipitated E1eci;rons (NASAIGSFC - D, J. W i l l i a m s )

The primary objective of t h i s experiment i s to s t u d yth e temporal and s p a t i a l behavior of medium t o high energye lec t rons a t l a w a l t i t u d e s in the ou te r zone and t o c o r r e l a t et h i s information w i t h f l a r s tu d ie s made during smum. The experiment m i n t ties of t rprec ip i ta ted e lec t rons i n gy range 40 Kev t

Measurements are obt;ained w i t h seven solid-stage detectors ,mounted i n a s h i e l d i n g head a t the end of a short boom. Fourof the seven detectors are used t o measure t r apped electrons andthe remaining three ape employed f o r p re c ip i t a t i o n and back-scattering measurements.

The ob jec t ive of t h i s experiment i s t o examine th elongi tude , la t i tu de and time var ia t ion of the neutron alpbedoflux, and t o s tudy re la t ionships with e n e rg e t ic p a r t i c l e t rap-ping, The ins t rument mnsis ts of a neutron de te ct or mountedapproximately 25 f e e t from the observatory on a long boom.The neutron detector monitors t h e t o t a l neutron f lux i t h eport iona l counter encased i n a s c i n t i l l a t o r material which i sa moderator f o r f a s t neutrons. The moderator i s surrounded bycharged-particle counters to "gate-off" th e neutron counterwhenever a charged par t ic le en ters th e moderator, T h i s reducest h e e f f e c t s of total neutron production w i t h i n t h e de tec t ingsystem.

energy interval t w o Mev to 10 Mev and consists of a He3 pra-

Low Energy Solar Cosmfc Rays (McDonnell-Douglas AeronautiosGorp,,- Santz Monica, C a l i f , , - A , J , Masley]The ob jec t ive of k h i s experiment i s t o i n ve s ti g at e s o l a rcosmic, rays; $0 re la te t h e remles t o s ol ar and ionosphericstudies, and to ca l i br a te ground-based multifrequency siom eterstat;ions.The detec tor i s designed t o measure the f lux and energylevel of low energy protons (f iv e t o 80 Mev) and alpha p a r t i c l e s(20 t o 150 MeV) ov r a n i n t e n s i t The sensor unitt o t h e d e te c to r uses tw o semiconductor part icle detectors

arranged i n t h e form of a telescope,

range from less than galacticbackground t o 3x104 particles/cm~-sec-steP.S o l a r and Galactic Cosmic Rays (CIT - E,C. Stone)

T h i s experiment will study t h e acceleration and i n j e c t I a nQf high-energy par t i c l e s by th e Sun, and the ir atorage and pro-pagat ion i n in terp lanetary space; the nature of' t h e smallf l u x e s of solar p a r t i c l e s t h a t produce polar cap absorption;and t h e shapes of t h e galac t ic pro ton , alpha , and e lec t ronspectra and t h e i r va ri at io n under s ol a r modulation.

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The exp er be nt uses three charged part icle te lescopeslocated in the observatory main body. The f i r s t i s an energyloss-range telescope con sis tin g of seven solid sta$e detec tors ,separated by various absorbers, arranged i n a s ing le s tack andsurrounded on t h e s i d e by a p l a s t i c s c i n t i l l a t o r an ti -c oi n-cidence counter. This telescope w i l l measure t h e d i f f e r e n t i a lenergy spectra of protons (0.4 t o 300 M w ) ~ a lpha p a r t i c l e s(0.4 t o 1200 Mev,) and e le c t ro ns (1 o 1000 Mew).The second i s an energy Poas Cerenkov telescope whichd e te c t s p a r t i c l e s a r r iv in g w i th in a cone of 35 degrees h a l f -angle w i t h re spec t to t h e ver t ica l and analyzes them for energyloss i n a solid s t a t e detec tor and veloc i ty in a quartz CerenkovRadiator. -D i f f e r e n t i a l energy spectra of protons (350 t o 100

Epev) a lpha pa r t ic le s (1400 t o 4000 Mev) and f o r L i , Be, B, C yM, and 0 p a r t i c l e s will be obtained.The t h i r d i s an energy loss telescope which detectsp a r t i c l e s a r r i v i n g within a cone of 4.5 degrees half-angle w i t hrespect tQ he v e r t i c a l and a l so analyzes them for energy loss i n

8 solid s t a t e d e te ct o r, This te lescope w i l l provide informationon large a o la r f l a r e s (protons: 17 t o 100 Mev; Alpha p a r t i c l e s :70 t o 1400 Mev).Magnetic F ie ld Measurements (NASA/GSFC - J, C, Cain)

The o.bjectivet of t h i s experiment is t h e understandingof the physical processes cr eat ing and a l t e r i n g th e main geo-magnetic f i e l d and the sources external t o the E ar t h ' s surfacecontr ibut ing to the ambient f i e l d i n th e F-layer.gro ss fe at ur es of surface magnetic anomalies will be locatedand mapped f o r u s e by geologists.inves t iga ted inc lude t i d a l o s c i l l a t i o n s of the lonosphsrpe byt h e g ra v i t a t i o n a l g r a die n ts of the Sun and Moon ( lu n i s o l a rmagnetic variat ions) and d iu rna l changes on q u i e t d a y s (SqlODuring periods of magnetic disturbance, the e f f e c t o f t rappedplasma and var ia t ions in t h e external pressure on the magneta-sphere will be eva lu at ed (Dst/DS). One of t h e main functionsof t h e analysis will be t o separate th e magnetic va r i a t i onsseen a t th e Earth 's surface t ha t ar ise from th e ionospherefrom those w i t h sources in the t r app ing and boundary regions.and elec tr , oje ts (auroral and equ ato ria l) am t o be investigatedand corre la ted w i t h other experimental data on th e spacecraft ,

If possible,The ex te rna l sources to be

Other e f fec t s such as longi tudinal pulsa t lons in f i e l d

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-25-

The detector consists of two Rubidium vapor magneto-meters which measure t o t a l ac l ar magnetic fi el d. In addition,t h e RubidLum Frequency divided by fo u r i s t on SpecialPurpose Telemetry t o allow study of smaller pulsa-t ion8 by sp la1 tachniques. The twin-ce l l mag t e r s a remounted a tmain body that the in te r fe rence Is less than 1g a m .accuracy of? th e measurement i s of t h i s order.e end of a Bong boom s u f f i c i e n t l y fa r from t h en e overa l l

The ob jec t ive of t h i s experiment is t o i n v es t i g at en a t u r a l magnetic f i e l d var ia t ion s wi th in t h e ionosphereand lower magnetosphere i n the frequency range of 0.01 t o1 MZ.Signals or ig ina t ing within o r above t h e ionosphere

have been detected at t h e Earth's 8wrface throughout t h i sfrequency range. Several species of micropulsations areknown t o e x i s t below 1 Hz, and hydromagnetic emissions Betweenone and five Hz have been found to exh ib i t a complex frequency-t i m e behavior, A t higher frequencies and a t high latitudes,auro ra l zone emissions ( i n bands below 500 Hz and from 500 t o1500 Hz) and extremely l o w frequency whistlers have been ob-served.Consequently, th e r e l a t i o n between t i m e - v a r y i n g magneticfields, charged part icle variat ions and electromagnetic radia-t i o n i n , o r near, t h e auroral zone w i l l be of s p e ci a l i n t e r e s t .The instrumentation consists of a t r i a x i a l s ea rc h c o i lmagnetometer located a t the end of a long boom.output represents th e instantaneous ampli tude of the f l u c tu a t in gcomponent of t h e ambient magnetic f i e l d i n t e n s i t y a t frequenciesbetween 0.01 and 1200 hz.

Electric Field Measurements (NASA/GSFC - T. L, Agqson)of ambient electric f i e l d i n t e n s i t i e s and of f ie ld gradientsi n t h e Ionosphere. The e l e c t r i c f i e l d i n t e n s i t i e s which maycause auroral and high geomagnetic l a t i t u d e e l e c t r i c u ur re ntw i l l a1so be measured, Time dependent field in te ns i t y changesw i l l be studied which are magnetic f i e l d a l ig n e d i r r e g u la r i t i e s ,plasma waves and/or irregular magnetic fluctuations,

The experiment consists of two 36)mfOOt ante nnas whicha c t as e l e c t r i c field sensors, The antenna and preamplifiersare mounted at; t h e e x t r e m i t i e s of th e two solar arrays.

Each sensor

This experiment provides one dimensional measurement

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The primary objec t ives of t h i s experiment are t h e measure-ment of t h e polarization, wave-normal direction, and the e lec-tPlc/magnetic (E/N) r a t i o of s ig n a l s in the frequency range38 HZ t o 30 Me .The secondary objectives include t h e measurement ofantenna impedance and current w i t h and without bias , t h emeasurement of t h e phase and ampli tude of V'LF t r a n s m i t t e rs igna ls , t h e me surement of t h e in tegra ted na tura l VLF noise.,and the measurement of th e observed ion-gyrofrequency w hi st le rs ,The l a t t e r measurements w i l l be compared w i t h t h e data observedby ion probeg and w i t h th e magnetometer observations.The sensors c o n s i s t s of three mutually perpendicular

magnetic loop antennas and one el e c t r ic dipole located a t th eend of a.long boom. signals from various inp uts ar e prepro-cessed by phase s h i f t i ~ nd adding i n d if fe re nt combinations.Various frequency bands w i t h widths of 120 Hz o r 2.4 kHz canbe se lec ted In the frequency range 30 Hz t o 30 kHz,

The primary sc ie nt i f ic object ive of t h e experiment i st o study th e e l e c t r i c field of waves such as whist lers overan. extended range of frequencies (10 Hz t o 295 kHz broadband;200 and 540 lcHz narrowband).measure t h e irnpedance of the exper iment ' s e lec t r ic d ipole an tennaa t several frequencies (8, 24, 104.5 and 285 kHz). Whistlerand emission data will be compared w i t h observations made s i m -ultaneously a t an exist ing network of whistler s tat ions, whichextend north-south from t h e Arct ic to t h e Antarctic (approxi-mately along 65 degrees W. geographic longitude),

It 1s known t h a t emission phenomena such as Chorus andh i s s are related t o par t i c l e f luxes such as those observed underauro ra l condi t ions , To incr ease understanding of these r e l a -tio nsh ips , th e measurements of t h i s experiment w i l l be corre la-ted w i t h data obtained simultaneously via other experiments onpar t i c l e f luxes ,posi t ive I o n composition w i l l be used for studying lower hybr idresonance phenomena.

A secondary objective is t o

Simultaneous data on elec tron de nsi ty and

This e x p e r b e n t shares the two 3o-foot antenna of t h eElectric F i e l d s Experiment.-FIIOP+


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-27 -MUNCH V.?3ffICI;E

The A370-po\r.nd OGO-P sa%e11i%eall b e launched w i t ha Thorad-Agena into an elabiptlca3 orbit w i t h an apogee of684 statute milies end a perigee of 249 miles.w i l l be i n c l in e d 82 degrees to t h e Equator and has a per lodof 99.8 minutes. !The o r b i t

The launch veh?..cLe consists o f a Thorad first stage anda n Agena-D second stage, The Thorad is a long tank vers ionOf t h e Thrust Au@;mentedThors (TATS) used t o launch previouspolar Orbiting Geophyshcal Observatories. The grea t e r burntime made p o s s i b l e by increasing the propel lan t capacity of t h eThor along w i t h increased burning t i m e for t h e three strap-onsobid propeblant rocket motors makes i t poss ib le t o boostabout 20 per cent more payload w i t h - the Thorad than tneo r i g i n a l TAT. The Thorad carries approximately 45,000 poundsof R J - l f u e l and IQ0,000 pounds of liquid oxygen. The threeThorad strap-an rocket motors provide 52,130 pounds of t h r u s tfor 37 seconds

Only one burn of t h e Agsna's 16,000-pound-thrust eng ineIS nece%saW t oo rb i t .3,837 pounds of U ~ HUnsymetrical dimethylhydrazine) fueland 9,660 pounds of IRFNA ( I n h i b i t e d red fuming n i t r i c ac id )oxidizer .

lace t h e OGO s racecraft i n the requiredFor t h e 8 O-P mission, !?he Agena carries approximately

The launch vehicle including t h e 18.7-foot f i b e r g l a s sclamshell shroud stands 3-09.5 f e e t high.The Launch a ndo w for 0G0-F 1.8 selected t o allow t h espacecraft t o remain i n sunl igh t dur ing i c s f i r s t 48 hoursi n space. To achieve t h i s o b je c t iv e , l i f t o f f i s scheduledfor l O : 3 2 a . m . EDl? on dune 5. The launch window closes a tb l : 2 6 a.m. EDT t h a t day.

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-28-

Event000-E'TYPICAL SEQUENCE OP FLIGHT EVENTS

SecondsAfter L l r -of fLi f t -o f f 0S t a r t f i r s t r o l l program 2 .CJStop f i r s t r o l l program - s t a r t f i r s tp i t c h program 16.0S o l i d motor burnout 38.6Eject solid motors 102Thorad Main Engine Cutoff 21? .Thorad Vernier Engine C u t o f f 228.Thorad-Agena separation 234 4Transfer WECO steering commands t o Agena 235.7Agena engine ignition 28d. 1Shroud separation 296.9Agena engine cu to f f 523 4OGO-P separation 630 .Begin Agena Yaw maneuver 533 5,Complete Agena yaw maneuver 663.9

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-29-COUNTDOWN MILESTONES POR THORABAOENA-D Oo - F LAUNCHEventCountdown ln l t l a t l o n7Thorad preparationWECO and Thorad telemetry checksDestruct ChecksS o l i d motor armingGantry removalAgena tankingAgena pressurizat onCountdown evaluation and startterminal count

Minutes-595-595-575T-525T-450T-360T-180T-85T-60

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Thorad PhaseAfter l i f t o f f t h e 'Phorad-Agena veh ic le rises v e r t i c a l l yw i t h i t s main engine and three strap-on so l id motors f i r i n g ,S t a r t i n g a t approximately 2 seconds a f t e r l i f to f f and con t in -u i n g u n t i l 16 seconds, t h e v e h i c l e r o l l s t o the desired f l i g h tazimuth of 187 degrees, The three s o l i d rocket motors providet h r u s t f o r approximately 39 seconds and are ejected a t about102 seconds af te r l i f t o f f , During t h e booster rocket f l i g h t ,a dog leg maneuver is necessary t o a t t a i n the 82-degree f i n a lo r b i t i n c li n a ti o n , This maneuver i s executed between 102and 124 seconds a f t e r l i f t o f f ,Main engine cutoff of t h e Thorad i s commanded by theWECO guidance system along with %he i n i t i a t i o n r>f' t h e Agerras ta r t sequence, A Thorad fuel dep le t ion switch car1 alsocommand main engine cutoff,

Agena PhaseSeparation of the Agena stage i s i n l t i a t e d by a commandfron t h e MECO ground station, and s m a l l r e t r o r o ck e t s are firedt o retard t h e f l i g h t of th e Thorad, About 33 seconds later theAgena and OGO-F spacecraft pitch maneuver i s i n i t i a t e d . Thep i t c h maneuver i s completed i n 13 sec, and the Agena enginei s s tar ted , During t h e 237-second Agena burn period, s t e e r i n gcorrection commands are t r a n s m i t t e d from t h e WECO grounds t a t i o n .A t T plus 297 seconds t h e nose fairing i s j e t t i so n ed .

And at T p l u s 523 secorrds t h e Agena main engine is s h u t dorm,OGO Separat ion

IXxriAng h e approximately lo7 seconds between Agenaengine cutoff and OGO separat ion , t h e v eh i c l e i s maintainedat an a t t i t u d e hor izon ta l t o the E ar t h ' s surface,Separation occurs a t T plus 631 seconds by firingexplosive b o l t s on t h e spacecra f t adapter, Compressed sprfngsthen push the OGO spacecra f t away f r o m t h e Agena stage at arate of about 4.5 feet per second,A few seconds a f t e r separat ion , the Agena veh ic le i syawed 90 degrees t o t h e r i g h t so t h a t any r es idua l p r o p e l l a n tt h a t might b e vented w i l l not contaminate t h e spacecra f t andw i l l tend t o inc rease tne separa t ion of t h e two orbiLs,


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0G0-F ExPFJWlENTERS & EXPERIMENTSDr. G. W. Sharp Atmotspheric DensityLookheed Missfle and Space Go.Dr, A. F. Nag y Electron Temperature & DensityUniversity o f MichiganDr, W e B e son Xonoepherlc DuctingSouthwest Center for AdvancedC. A. Reber Neutral Atmospheric CompositionGoddard Space F l i g h t CenterDr . R. A. Pickett Atmospheric Ion Concentrationaoddard Space Flight CenterDr. W, Bo Hanson 1on Maas SpecLrometerSouthwest Center for Advanced

Studies

and Mass

StudiesD r . D. Mc?KeownFaraday LaboratoriesR . W . KreplinU. S. Naval Research Lab.Dr. D. E, %doA i r Force Cambridge Research

LaboratoriesProf, V . H. RegenerUniversity o f New MexicoPro f . J, E . BlamontUniversity of ParisDr. M. A. ClarkAerospace Corpora$ionProf. C. A, B a ~ e hUniversity o f ColoradoProf'. J , E, BlamontUniversity of Paris

Energy Transfer ProbeSolar X-Ray EWisslonsSolar W (160 t o 16008) Emissions

Solar Wosurvey (1,850 toAirglow and Aurora Bnlssions

3,500 A )

Celestial Lyman-AlphaUV Photometer

06,300 A Airglow Emission

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-33-Dr. D. S. EvansOoddard Space F l i g h t CenterProf', T, A. ParleyUnivers i ty of' Cal i fo rn ia a tD r , D . J . W i l l i a m sGoddard Space F l i g h t CenterProf, J. A . LockwoodUnivers i ty of New Hampshire

I;os Angelea

Dr. A. J . MaaleyMcDonnell-Douglas Astronautlcaco.

Prof, E. C , StoneC a li fo r ni a I n s t i t u t e of Tech-no ogyD r . J. C. CainGoddard Space F l i g h t CenterDr. E. J, SmithJ e t Propulsion Laboratory

Low-Energy Auroral ParticlesTrerpped and Precipi tated Elect rons(45 t o 1,200 kev)Tra ped and Pr ecip i ta te d ElectronsNeutron Monitor

(PO kev t o 2 mev)

Low-Energy Solar Cosmic Rays

Solar and Galactic Cosmic Rays

Magnetic Fie ld MeasurementsMagnetic Fie ld Fluctuat ions

D r . T. L. Aggson Electric F i e l d Measurementsaoddard Space P l i g h t CenterP r o f . R. A. H e l l i w e l lStanford Univers i tyProf', T. LaaspereDartmouth CollegeP r o f . T. M. DonahueUnivers i ty of Pit tsburgh

VLF Pola r i za t ion and WaveNormal DirectorWhistler and Low FrequencyEle c t r i c FieldsSodium Airglow

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-34-OCCO-F PRO(IRAM T E AM

The following key officials are responsible for th eOrbi ting Geophysical Observatory s a t e l l i t e program:NASA Headquarters

Dr. John E. Naugle, Asaroclate Admhlatrator for SpaceJesse Mitchell, Director, Phyarlcs and Astronomy ProgramsThomas L. Flschettl, Cleophyslcal Observatories Program

Science and Applications

ManagerD r . Robert F. Fellows, OClO-F Program ScientistW i l l i a m L. Lovejoy, Age= Program ManagerQ , M. Tmrszynskl, Associate Administrator for Trackingand Data Acqulsltion

NASA Qoddard Space Flight CenterDr. John F. Clark, DirectorWilfred E. Scu l l , 000 Projec t ManagerNelson W. Spencer, 0 0 - F Project S c i e n t i s tNASA L e w i s Research CenterSeymour C. Hlmmel, Assistant Director for Launch Vehic lesH, Warren Plohr, Age- Project ManagerRoger S, P a l m e r , OW-F Mission Engineer

Prime ContractorSpacecraft design, development, fabrlcatlon and t e s t ,T RW Systems, Inc, , Redondo Beach, Cali f .

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-35-MaJor Suboontractors

Battery Cells -0 (3ulton Industries, Inc., Hetuchen, N.J.Gyroscopes -- Minneapolis-Honeywell Corp., Boston, Mass.Horizon Scanners -- American Standard, Advanced TechnologyDivision, Mountain V i e w , Calif.Power Converters -- ITT Industrial Products Dlv . , SanFernando, Calif'.Reaction Wheels 0- Bendix Eclipse Pioneer Dlv., Teterboro,N.J.Solar Cell Module8 -- TRW Systems, Inc. , Redondo Beach,Solar Cells -- Hoftman Electronics Corp., El Monte, Calif,Calif.Static Inverters -- Kinetics Corp., Solana Beach, Calif.Tape Recorders -0 RCA Astro-Electponics Division, Princeton,

N e J.Tape Transporters (In Ground Support Equipment) -- AmpexCorp., Redwood City, Calif.

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ogo-f press kit

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