imp-i press kit

8/8/2019 IMP-I Press Kit

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WO 2-4155ATI ON AL AERONAUTICS AN D SPACE ADMINISTRAT IONWASHINGTON, D .C 20546 w o 3-6925

RELEASE NO: 71-35I

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: WEDNESDAY3 A.M.March 10, 1971

IMP-I

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WEDNESDAY, A.M.March 10, 1971RELEASE NO: 71-35

NASA TO LAUNCH EIGHTH IMP

The eighth spacecraft in the National Aeronauticsand Space Administration's Interplanetary Monitoring Plat-form (IMP) program is scheduled to be launched March 12, 1971,by a three-stage Delta M-6 rocket from Cape Kennedy, Fla.

Called -- .MP-I- . -.the 635-pound automated space physicslaboratory i s the largest and most advanced spacecraft in theNASA Explorer series. I t s major engineering innovations in-clude the most advanced encoder-digital data processor systemever flown on an unmanned NASA satellite, It is also the largestand most complex spacecraft ever built at the NASA GoddardSpace Flight Center, Greenbelt Md.

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-2 -The IMP-I scientific mission is to continue the

pioneering investigations of the seven earlier spacecraftin the series which began with the launching of Explorer 18,No-v. 18, 1 9 6 3 . Scientific results from the program to dateinclude defining the nature and extent of the Earth's magnet-osphere and vastly increasing man's knowledge of the turbulentinterplanetary space environment, In addition, IMP spacecrafthave provided warnings of possible solar flare radiation hazardst o astronauts during Apollo flights to the Moon,

IMP-I, which will be called Explorer 43 .after orbit isachieved, carries instrumentation for 12 scientific experimentsand one engineering experiment. The scientific experiments,representing collaborative efforts of nine V.S. universities,the Atomic Energy Commission and NASA, are designed to studyenergetic particles, solar plasma, electric and magnetic fieldsand radio astronomy. The electric fields and radio astronomyexperiments are "firsts" for the IMP program.

The engineering experiments an on-board. computer willalso be used t o process data from some of the scientific instru-ments. It will be the first of its kind to assess its potentialfor future unmanned spacecraft mfssions

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-3-The p rimary s c i e n t i f i c o b j e c t i ve s o f t h e 1 2 s c i e n t i f i c

expe r iment s are t o i n v e s t i g a t e e n e rg e t ic p a r t i c l e s , e s p e c i a l l ysOlar and g a l a c t i c co sm ic rays ( s i x e x p e r i m e n ts ) , s o l a r p la sm a( t w b e x p er i m en t s ), m ag ne ti c and e l e c t r i c ' f i e l d s ( t h r e e e x p er i -menta) ana padio astronomy (one exper iment) e

T h i p w i l l b e th e mos t demandin mission t h e Delta rocketivsn d u r i n i t s 1 1 - y e a r h i s t o r y ,

I t must .be launched on a v e r y p r e c i s e t r a j e c t o r y s bt h a t t h e s c i e n t i f i c i n st ru m en t s a b oa rd t h e s p a c e c r a f t c a n makemeasurements w i t h t h e Sun a t a s p e c i f i c a ng le ' t o t h e IMP'S o r b i t , ,T h i s r e q u i r e s a la un ch window of onl y 1 0 rninu6es each 2 4 hoursan d t o - th e - se c o nd a c c u r a c i e s i n t h e f i r i n g times of t h e t h r e e -s t a g e r o c k e t and s i x s t rap-on motors a t v a r io u s a l t i t u d e s andl o c a t i o n s a r o u n d E a r t h .

I t must h i t a small, imaginary t a r ge t i n spa ce ' w i t h t h eaccuracy of a s k i l l e d marksman, and a t a sp e e d n e a r b u t n o te x c ee d i ng E a r t h e s c a p e v e l o c i t y .

Thfs w i l lv e r s i o n o f t h e

be t h e f i r s t l aunch f rom Cape Kennedy of t h i sDelta.planned for IMP-I i s h ig hl y e l l i p t i c a l , r a ng in gL high pofnt; (apogee) of '121,,QOQ s t a t u t e m il es t o


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-4 -P r o je c te d o r b i t a l p e r io d i s j u s t un de r f o u r days . Even-

t u a l l y t h e o r b i t w i l l change because of t h e g r a v i t a t i o n a l i n -f l ue nc es of t h e Ea r th , Moon and Sun t o an apogee of about113 ,000 miles and a p e r i g e e o f 8 ,000 m i l e s .

T h e sp a c e c r a f t i s e x p ec t ed t o be f u l l y o p e r a t i o n a l ab ou t30 d a y s a f t e r l a u n c h .

M is si on o b j e c t i v e s a r e :"Continue t h e d e t a i l e d e n e r g e t i c p a r t i c l e s s t u d i e s begun

. w i t h e a r l i e r I M P S .*Study t h e q u i e s c e n t p r o p e r t i e s of t h e i n t e r p l a n e t a r y

mggnet ic f i e l d and i t s d y n a m i c r e l a t i o n sh i p w i t h t h e f l o w ofp a r t i c l e s f rom t h e S un.

%Cont inue t h e s o l a r f l a r e moni tor ing program.* Im pro ve o u r u n d e r s t a n d i n g of Sun -E ar th r e l a t i o n sh i p s .%Study l o w f requ ency r a d i o waves f rom t h e E a r t h ' s magnet-

o sp h e r e , t h e s o l a r c o r o n a a n d t h e Milky Way i n o rd e r t o d e t e r m i n et h e i r r e l a t i o n sh i p t o t h e m a g ne t o io n i c p r o p e r t i e s o f t h e solars y s t e m and t h e g a l a x y .

%S,tudy t h e E a r t h ' s e l e c t r i c f i e l d f r o m i n t e r p l a n e t a r y s p a c e .* C on t in u e e v o l u t i o n a r y d ev el op me nt o f r e l a t i v e l y i n ex p en -

s i v e , s p i n - s t a b i l i z e d s a t e l l i t e s f o r i n t e r p l a n e ta r y i n v e s t i g a t i o n s


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-5-I nc lu de d i n t h e o v e r a l l IM P program a re t h e two Anchored

I n t e r p l a n e t a r y M on it or in g P l a t fo r m s p a c e c r a f t , AIMP-D ( E x p l o r e r3 3 ) and AIMP-E (Exp lore r_-- 35), a l s o Goddard-buil t and managed.T h e y were l a u nc h e d i n 1 9 6 6 and 1 9 6 7 .d e s i g n e d for l u n a r o r b i t s and are s t i l l opera t iona l . .

B o t h s p a c e c r a f t were

They made m aj or c o n t r i b u t i o n s t o s c i e n t i f i c knowledgea n d u n d e r s t a n d i n g o f t h e n e a r l u n a r a nd L n t e r p l -a n e t a r y e n v i r o n -ment inc lud ing t h e f i n d i n g- t h a t p o s i t i v e i o ns f r o m t h e solarwind i m p ac te d d i r e c t l y o n t o t h e Moon's s u r f a c e a n d t h a t a s o l a rwind v o i d e x i s t s d i r e c t l y be hi nd t h e Moon. These f i n d i n g sa ided i n p la n ni n g Ap ollo m is s io n s, p a r t i c u l a r l y i n p r o vi d in g t h ef i r s t d e t a i l e d i n f o r m a t i o n on t h e e l e c t r i c a l c o n du c t i v i ty andi n t e r n a l t e m pe r a tu r e s o f t h e Moon.

R e s u l t s f r o m t h e E a r t h - o r b i t i n g IM P s p a c e c r a f t h a v eg r e a t l y expanded o u r u n d e r s t a n d i n g of t h e E a r t h ' s magnetosphereand t h e t r a n s i t i o n r e g i o n b e t w e e n t h e magne tosphe re and in t e r -p l a n e t a r y s p a c e

'rhe magnetosphere i s a huge , t ea rd rop-shaped enve lopesu r r o u n d i n g t h e E a r t h whi'ch contains t h e Van Al len ra df a t lo n

e _ . -b e l t s , It i s formed by s o l a r wind impinging on t h e E a r t h l smagnet ic f i e l d . The soLar wi n d , t r a v e l i n g a t su p e r so n i c speeds ,t e n d s t o co mpr es s t h e Sun s i d e o f t h e magnetosphere, w h i l e t h er e g i o n b e h i nd t h e E a r t h , away from t h e Sun, i s d i s t e n d e d a ndt r a i l s of f beh ind t h e E a r t h f o r s e v e r a l m i l l i o n miles much l i k et h e t a i l o f a comet.

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-6-IM P f i n d i n g s h av e r e s u l t e d i n p u b l i c a t i o n o f more t h a n

125 s c i e n t i f i c p a pe rs . Key r e s u l t s r e p o r t e d to d a t e i n c l u d e :"F i r s t ac cu ra te measurement s o f t h e i n t e r p l a n e t a r y mag-

n e t i c f i e l d .*D et ai le d mapping of t h e shock f ron t boundary o f t h e

magnetosphere and t h e t u r b u l e n t t r a n s i t i o n r eg io n- -t he mag-netopause--behind t h e boundary.

% F i r s t d e t a i l e d i n f or m a ti o n on t h e magnetosphere t a i lr e g i o n

%Discovery of a m a g n e t i c a l l y n e u t r a l area i n t h e magneto-s p h e r e t a i l - - c a l l e d t h e n e u t r a l sh e e t - - c a u se d by m a g n e t i c l i n e sof f o r c e moving i n o p p o s it e d i r e c t i o n s .

"Discovery o f e n e r g e t i c e l e c t r o n s i n t h e n e u t r a l s h e e twhich may be t h e s o u rc e of r a d i a t i o n c a us i n g t h e a u r o r a asw e l l as rep len i shment o f t h e Van Al len ra d ia t i on b e l t s ,

The IM P s e r i e s of s c i e n t i f i c s p a ce c ra f t i s p a r t o f t h es p ac e e x p l o r a t i o n pr ogr am d i r e c t e d by N A S A Q s O f f i c e o f SpaceSc ience and Appl i ca t ions . N A S A ' s Goddard Space F l ig h t Cen t e r ,where IM P s p a c e c r a f t a re b u i l t , i s r e s p o n s i b l e f o r IM P p r o j e c tmanagement. The EMR-Aerospace Sciences, College Park , Md. ,a s s i s t e d i n s p a ce c r af t s y s t e m s i n t e g r a t i o n a n d e n vi r on m en t alt e s t i n g . Prime c o n t r a ct o r f o r t h e D e l t a l aunch rocke t i s McDonnelDouglas Ast r on aut ics Co, , Hunt ington Beach, C a l i f .

(END OF GENERAL R E L E A S E ; BACKGROUND INFORMATION F O L L O W S )

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T HE IMP -I SPACECRAFT

A s t h e l a r g e s t a n d most complex s p a c e c r a f t i n t h eNASA Ex pl or er s e r i e s , t h e 635-pound I M P - I resembles a l a r g edrum w i t h 1 6 s i d e s . I t s m a i n s t r u c t u r e i s s i x f e e t h ig h b yf o u r a nd o ne -h al f f e e t i n d i a m e t e r . The u p pe r p o r t i o n o ft h e main s t ruc ture conta ins an a luminum honeycomb s h e l f onw hich t h e s c i e n c e i n s t r u m e n t a t i o n and e s s e n t i a l s p a c e c y a f te l e c t r o n i c e q u i p m e n t a re housed. The lower po r t io n has an1 8 - i n c h t h r u s t t u b e t o accommodate t h e D e l t a t h i r d s t a g e m o t o r .To a v oi d r a d i o f r e qu e nc y i n t e r f e r e n c e a nd to m a i n t a i np r o p e r t h e r m a l c o n t r o l , t h e s c i en c e s e c t i o n of I M P - I i s i n su -l a t e d by p r o t e c t i v e m e t al c o ve rs a n d s i d e p a n e l s . The e x p e r i -ment- to -spacec raf t -we ight r a t i o i s one o f t h e hi gh es t of NASA'sunmanned s a t e l l i t e s : 2 1 5 po un ds v e r su s o v e r a l l wei g ht o f 635pounds.Power i s obta ined f rom 48 p a n el s of s o l a r c e l l s a rr a ng edi n t h r e e r i n g s on t h e o u t s i d e s u r f a c e . T he se p r o v id e en er gyt o o p e r a t e t h e sp a c e c r a f t a n d c h a r g e t h e 1 2 - p ~ u n dpackage ofs i l v e r - c a d m i u m b a t t e r i e sFour booms, fo l ded dur ing l aunch , a r e a t t ac hed to t h ee x t e r i o r of I M P - I . Two of t h e s e , abou t 1 2 f e e t l o ng , c a r r ys e n s o r s , and tw o, e ac h f i v e f e e t l o n g, a re u s e d f o r t h e a t t i -t u d e c o n t r o l s y s t e m . The a t t i t u d e c o n t r o l s ys te m, u s i n gFreon-14, w i l l h e l p m a i nt a in t h e p r o p er s p i n - s t a b i l i z e d o r i en -t a t i o n p e rp e nd i cu l ar t o t h e e c l i p t i c p la ne . T h i s s y s t e m , animproved ve rs ion o f a s i m i l a r s y s t e m flown on AIMP-E ( E x p l o r e r3 5 ) , i s o p e r a t e d b y ground command.S i x a n t en n a s , f o u r 1 5 0 f e e t long and two 20 f e e t l o n g ,w i l l be d ep lo ye d a f t e r o r b i t i s a t t a i n e d t o m a k e e l e c t r i c fieldmeasurements and radio as t ronomy observa t ions .Uni qu e e n g i n e e r i n g f e a t u r e s o f t h e I M P - I i n c l u d e :*An encoder and d i g i t a l da t a pro ces sor , t h e mos t advancedand most powerful d evi ce of i t s type ever flown on an unmannedNASA s p a c e c r a f t . T h i s d e v i c e u s i n g o nl y f o u r wat ts of power,

i s f i t t e d i n t o a ten- inch volume area o f t h e s p a c e c r a f t . I tc o n t a i n s 328,000 MOSFET d e v i c e s ( m e t a l . o x i d e s i l i c o n f i e l d e f f e c tt r a n s i s t o r s ) and 500- s e p a r a t e da ta c o u n t e r s .*An o p t i c a l - a s p e c t sys te m c o n s i s t i n g o f s e n so r s d e s i g n e dto g iv e t h e s p i n a x i s o r i e n t a t i o n o f t h e s p a c e c r a f t w i t h r e s p e c t. t o E a r t h .

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-8 -"A spin synchronous clock which is essentially "timed"

with the rokation rate of the spacecraft.*The range and range-rate tracking system which permitspinpoint tracking by ground stations.IMP-I, designed, built and environmentally tested atthe Goddard Space Flight Center, is planned for an operatinglifetime of at least one year.

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-9-THE SCIENTIFIC OBJECTIVES

IMP-I, weth its vastly increased size ai eight, datahandling capability and new and advanced sensors, representsa significant step forward in the NA S A program of exploringspace.Earlier and less sophisticated IMPs mapped in broad termsthe interplanetary region, the magnetosphere, and studiedsolar and galactic cosmic rays and other aspects of the complexsolar-terrestrial relationship over a significant portion o fthe most recent 11-year solar cycle. IMP-I will, if S U C C ~ S S ~ U I - ,make contributions beyond this basic exploration role.Its 12 scientific experiments are designed to investigatethe complex mechanisms and processes in the interplanetaryenvironment which should lead to understanding how the variousphenomena relate t o each other. For example, the number andtype of energetic particles trapped in the magnetosphere a r efairly well known from early investigations. How they gotthere, what the acceleration mechanisms are and how they a m" l o s t " r e ma i m a mystery.Two additional spacecraft remain to be flown in the IMPprogram. These are IMPs H and J, currently scheduled for

launching in 1972 and 1973, respectively. These spac'ecraft wiE3.be configured like IMP-I, although they will carry somewhatdifferent instruments and will be placed in very high circulai-'orbits about half the distance to the Moon.Energetic Particles-Cosmic Rays

The six energetic partlcles-solar and galactic cosmic rayexperiments comprise the major complement of IMP-I experimentsand are viewed as potentially the most significant in terms ofexpanding our knowledge of these forces. They represent theNost comprehensive and intensive effort of its. type ever flownon a single spacecraft.

Before mail can function in interplanetary space, he mustfirst learn more about eTf'6cts of cosmic rays End where in spacethese lethal particles may dominate the environment,

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Cosmic r a y s a r e a c t u a l l y h i g h e n er g y p a r t i c l e s , some ofwhi ch c a r r y e n e r g i e s r a n g i n g f ro m a m i l l i on t o a b i l l i c n - b i l l i o ne l e c t ro n v o l t s . They c o n s i s t p r i m a r i l y o f p r o t o n s ( h i g h energyhydrogen nuc le i ) a l p h a p a r t i c l e s ( he li um n u c l e i ) and h e a v ie rn u c l e i . Some are so powerful t h e y can ram through a t h r e e - f o o tl ead wallCosmic r a y s that; come from deep space are c a l l e d g a l a c t i ccosmic r a y s , w h i l e cosmic r a y s from t h e Sun a r e c a l l e d s o l a rcosmic r a y s .Galac t ic Cosmic Rays . What p r od u ce s g a l a c t i c co sm ic r a y si s n o t c l e a r l y u n z r s t o o d . Cosmic r a d i a t i o n fro m g a l a c t i c s o ur c e si s p r e s e n t a t a l l t imes i n t h e s o l a r s y s t e m . The E a r t h ' s magnet icf i e l d i s n o t s t r o n g enough t o d e f l e c t them.

a t w h i c h t h e y a r e found near E a r t h d e c r e a s e . T h i s i s c a l l e dt h e Forbush decrease and i s observed when a l a r g e s o l a r f l a r eeven t occurs on t h e Sun. I t i s b e l i e v e d t h e i n t e n s e ' m a g n e t i cf i e l d l i n e s i n t h e tongue of plasma t h a t streams out f rom t h eSun envelops t h e E a r t h and i s s t rong enough t o d e f l e c t g a l a c t i ccosmic r a y s , D e t e c t o r s f l o w n o n e a r l f e r IMP s p a c e c r a f t haveshown t h a t d u r i n g p e r i o d s of minimum s o l a r a c t i v i t y i n t h e11-year s o l a r c yc l e , t h e a r r i v a l of g a l a c t i c cosmic r a d i a t i o nt e n d s t o i n c r e a s e .

Only dur ing t imes of i n t e n s e s o l a r a c t i v i t y do es t h e r a t e

The i n t e n s i t y of c os mic r a d i a t i o n v a r i e s w i t h t h e l a t i t u d eo f E a r t h . I t i s more in t ense a t t h e p o l e s . S i n c e c osmi c rayp a r t i c l e s h ave t re me nd ou s e n e r g i e s , t h e y p e n e t r a t e d e e p l y i n t ot h e E a r t h ' s atmosphere. When t h e s e f ast- mo vin g p a r t i c l e s c o l l i d ew i t h p a r t i c l e s i n t h e atmosphere t h e y produce many ki nd s of lower-e n e r g y r a d i a t i o n .

Solar Cosmic Rays e Although t h e i r composi t ion i s sJ.mi3.a~s o l a r c o s m i c r a y s have l e s s e ne rg y t h a n t h o s e of g a l a c t i c gr1gJ.n.Sola r cosmic rays s t r e a m fro m t h e - Su n d u r i n g p e r i o d s o f s o l a re v e n t sb e in g e j e c t e d i n t o t h e ' s o l a r s ys te m. Those t h a t r e a c h t h eE a rt h , p a r t i c u l a r l y t h e p r ot on s , i n t e r a c t w i t h t h e F : a r t h l aa tm o sp h er e a nd c au se m a gn e ti c s t o r m s , r a d i o b l a c k o u t s , a u r o r a ld i s p l a y s and othel? phenomena,

They r e s u l t i n " cl ou ds " o f h i g h l y c h ar ge d part; icl .es

The s i x . c h a r g e d p a r t i c l e e x pe ri m en ts c a r r i e d by I M P - I a red es i gn e d t o s t u dy b o th g a l a c t i c and s o l a r cos mic r a y s . Thesee x p e r i m e n t s , e s s e n t i a l l y , w i l l measure p a r t i c l e i n t e n s i t y ,c o m p o s i t i o n a n d d i r e c t i o n . They i n c l u d e :-mor e-.


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"Goddard Cosmic R a y Experiment . Provided b y the Goddard SpaceF l i g h t C e n t e r , t h i s p ac ka ge c o n s i s t s o f t h r e e t e l e s c o p e s t omeas ure ve ry low en er gy , low ene rg y and medium ene:,gy s o l a ra n d g a l a c t i c c o sm i c r a y s , Of p a r t i c u l a r i i n t e r e s t w i l l b e i n v e s t i -g a t i o n s o f t h e f l o w p a t t e r n s an d i s o t r o p i c c o mp os it io n of t h ep a r t i c l e s . The d e t e c t o r s weig h a lm o st 27 pounds and w i l l usean ave rage of fou r watts of p ower . The P r i n c i p a l I n v e s t i g a t o ri s D r , Frank B e McDonald o f Goddard.* Ga l a c t i c a n d So l a r Pa r t i c l e C o m p o s i t i o n a n d Sp e c t r a E x p e r i m e n t ,Provided by t h e Un ive rs i ty o f Chicago , t h i s i n s t r u m e n t w i l lmeasure h igh energy sp ec t r a , nuc l ea r compos i tion and e l ec t r on sof v a r i o u s e n e r g i e s . I t c o n s L s t s p r i m a r i l y o f t w o t e l e s c o p ed e t e c t o r s , i n c l u d i n g a low energy te l es co pe whlch i s t h e p r o t o -typ e of one scheduled to f l y o n t h e P i o n e e r F and G J u p i t e rm i s s io n s i n t h e m i d - 1 9 7 0 s . The package weighs 18 pounds andu s e s f o u r wat t s of p ower . The P r i n c i p a l I n v e s t i g a t o r i s D r . J , A ,Simpson of t h e U n i v e r s i t y of Chicago.*Low Energy P a r t i c l e De te ct or Experiment . Provided b y t h eUn ive rs i ty of Iowa, t h i s i s a s p ec tr o me f er c o n s i s t i n g o f t h r e ec y l i n d r i c a l cu rve d p l a t e s and r e l a t e d e l e c t r o n i c e qu ip men t. Itw i l l s t u dy t h e d i f f e r e n t i a l en er gy s pe ct ru m, a n g u la r and s p a t i a ld i s t r i b u t i o n a nd te mp or al v a r i a t i o n o f e l e c t r o n s a nd p ro t o ns .Weighing about . f i v e pounds, t h e p a c k a g e r e q u i r e s f o u r watts ofpower. P r i n c i p a l I n v e s t i g a t o r i s D r . L . A . Frank, Universi t 'yof Iowa.* E n e r g e t i c P a r t i c a l E xp er im en t. Des ig ne d to s t ud y t h e a c c e l e r a -t i o n of e l e c t r o n s a t t h e Sun and t h e i r i n j e c t i o n i n t o i n t e r -p l a n e t a r y sp a c e . P r ov i de d by t h e U n i v e r s i t y of C a l i f o r n i a , itc o n s i s t s o f f o u r d e t e c t o r t e l e sc o p e s wei gh in g a b ou t s e ve n p ou nd s,r e q u i r i n g 1 . 5 wat t s o f p ower . The P r i n c i p a l I n v e s t i g a t o r isD r . Kinsey A . Anderson o f t h e U n i v e r s i t y o f C a l i f o r n i a a tBerkeley .*Sol ar Proton Moni tor ing Exper iment . Provided b y t he Appl i edPhysics Labora tory of t h e Johns Hopkins Unive rs i ty , i t was f i r s tflown on IMP-F ( E x p l o r e r 3 4 ) and IMP-G to prov ide con t inuousand sy ste mat ic measurements of s o l a r pro ton s coming f rom t h e Sun,During Up0110 m i ss i o n s 8 t h rough 1 4 t h i s i n fo rma t ion was usedto i n s u r e a s t r o n a u t s a f e t y f rom p o t e n t i a l r a d i a t i o n h a z ar d s ,Data from t h i s exper iment w i l l b e r e l e a s e d t o t h e s c i e n t i f i ccommunity when s o l a r p r o t o n e v e n t s o c c u r . I t w i l l employ f i v ed e t e c t o r s u s i n g a b o u t 1 . 3 wat t s o f power and weighs e i g h tpounds. D r , C . Bostrom of APL i s t h e P r i n c i p a l I n v e s t i g a t o r .

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*Solar and Distant Mqgnetosphere Electron Experiment, Thiscomplex device will determine the characteristics of cosmicray electrons and posit-ons of various energies using a colli-mated electron detector, a background detector and a gamma-rayspectrometer. It was provided by Dr, T. L. Cline of the GoddardSpace Flight Center. I t s weight;is eight and one-half pounds,with two watts of power required for operation,Solar Plasma

The solar plasma or solar wind is a str4eam of chargedparticles speeding constantly into the solar system f rom theSun at supersonic speeds. The electrons and protons which makeup the solar wind arrive at the bow of the Earth's magnetosphereIn abou t equal numbers.o f about 1l.years. During periods of maximum activity, thestream s o l a r plasma increases greatly and has disruptive effectsupon the magnetosphere, frequently causing disruption of short-wave radio transmissions and communications undersea cables.

I

The Sun exhibits a cyclic change of activity with a duration

There is also a cycle of about 27 days corresponding tothe rotation of the middle portion of the Sun's surface. Chargedparticles and a lesser number of heavy atomic nuclei are expelledat tremendous speeds. Scientists believe the solar wind isan extension of the Sun's atmosphere or corona, During solarevents, solar wind particles attain speeds approaching thevelocity of light.is that it compresses the magnetic field closer to Earth on thesunside and distends the tail, or anti-solar side to a distanceof millions of miles, forming a comet-like aerodynamic shape.

One of the effects of the solar wind on the magnetosphere

The two IMP-I solar plasma experiments are:"Goddard Plasma Experiment. Provided by the Goddard Space FlightCenter, it consists of a complex 12-pound device to measure thebulk, velocity, density and parallel and perpendicular tempera-tures of hydrogen and helium ions in the solar wind at variousenergy ranges. It will use almost five watts of power. ThePrincipal Investigator is Dr. K, W, Ogilvie of Goddard.

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/A v a r i e t y of' magnetic fields e x i s t i n t h e u nt v er s e, En t h es o l a r system the S u n ' s magnetic f i e l d a f f e c t s t h e movement ofp a r t i c l e s i n s pa ce . This f i e l d i s a l t e r e d d r a m a t L C a l l y by t h ep e r i o d i c d i s t u r b a n c e s o c c u r r i n g on t h e Sun. Near E a r t h , o fc o u r s e , i s t h e t e r r e s i r i a l magnetic f i e l d , e n c lo s e d i n t h emagnetosphere. The e x i s t e n c e of g a l a c t i c m ag ne tic f i e l d s i salso th eo ri ze d. The magnetometer i s t h e p r i m a r y i n s t r u m e n tured on b o z r d s p a c e c r a f t t o s t u d y m ag netic f i e l d s .

A l i t t l e known e l e c t r i c c u r r e n t sy s te m f lo wi n g w i t h i n t h em ol te n, m e t a l l i c c or e of t h e E a r t h i s r e s p o n s i b l e f o r t h eE a r t h ' s main magnetic f i e l d .f o r m s a p o s i t i v e - n e g a t i v e f i e l d , Many v a r i a t i o n s o c cu r i n t h i sf i e l d . These e f f ec t >; can b e d e t e c t e d f o r th o us a nd s o f m i l e si n t o s p a c e . The f a c t t h a t t h e va ri at i . on s move slo wly westwardi n d i c a t e s t h a t t h o crusSc and core of t h e Ear th r o t a t e a t s l i g h t l yd i f f e r e n t i q a t e a .

The c o n f i g u r a t i o n of t h e s e c u r r e n t s

D e t a i l e d k nowledge of t h e main e l e c t r i c f i e l d o f t h e E a r t h1s s t i l l s c a r c e , It; i s e x p e c t e d t h a t IMP-I w i l l shed newl i g h t o n t h e su b j , e c t .

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The three magnetic electric field instruments carriedby IMP- I are:"Qirect Current Electric Fields Experiment. Provided byGoddard, this 50-pound device is the heaviest on board thespacecraft. It consists of four 150-foot-long and two 20-footantennas which will be deployed after IMP-I attains orbit. Theobjective fs to make measurements of the electric field toobtain detailed direct current and low frequency alternatingelectric field information. A sfmilar electric field meter,with shorter and fewer antennas, was carried on OGO 5.Principal Investigator is Dr. Theodore L . Aggson of Goddard."Alternating Current Electric and Magnetic Field Experiment.This collaborative University of Iowa-University of Minnesota-Goddard Space Flight Center experiment, weighing 30 and one-half pounds, will study the origin and characteristics ofnaturally-occurring radio noises in the Earth's magnetosphere,in the magnetosphere transition region and the solar wind.It will also permit low and high frequency range studies tobe made of magnetic and electric fields. Special devices willcollate radio intensity data with measurements of electronand proton energy distribution data obtained from the Univer-sity of Io wa ss Low Energy-Particles Experiment Coupled withthis is a device provided by the University of Minnesota,capable of measuring electric fields in a variety of low andhigh frequency ranges. Total power required will be nine andone-half watts. Principal Investigator is Dr. Donald Gurnett,University of Iowa.%Magnetic Field Experiment. The third and final instrument inthis category is a Goddard three-orthogonal component fluxgatemagnetometer. Its purpose is to make precise measurements ofthe interplanetary field, the magnetosphere transition regions,the magnetosphere proper and the tail. The magnetometer.weighsalmost eight pounds and requires two and one-half watts of power.Principal Investigator is Dr. Norman F. Ness of Goddard.

Radio Astronomy InvestigationsFor the first time since the inception of the IMP series,a radio astronomy experiment has been selected for IMP-I.

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Alt ho ug h r a d i o a st ro no my i n v e s t i g a t i o n s d a t e ba ck t o t h ep io ne er in g e f f o r t s i n 1 9 3 2 o f Karl G . Jansky , a B e l l Telephones c i e n t l s t , rad io a s t ronomy as a s p e c i a l i z e d b ra nc h o f s c i e n c ed i d no t r e c e i v e a n y g r e a t i m p e t u s u n t i l a f t e r World War I1when l a r g e g round-based ob se rv a t o r i e s were b u i l t .

The f i r s t i n t e n s iv e e f f o r t s to s t u d y e x t r a t e r r e s t r s a lr a d i o e m i s s i o n s from a s p a c e c r a f t o c c u r r e d w i t h E x p l o r e r 38(Radio Astronomy Explorer-A) laun ched J u l y 4, 1 9 6 8 . T h i ss p a c e c r a f t c o n t i n u e s t o t r a n s m i t e x c e l l e n t data i n lowf requency ranges which canno t pene t ra t e t h e E a r t h ' s a tmosphere .The I M P - I r a d i o as tr on om y r e c e i v e r w i l l c o n t i n u e p i o n e e r i n gs t u d i e s b ei n g c a r r i e d o u t by Explore r 38.

%Radio Astronomy Expe rime nt.-Mlhryland ( impedance probe and rad io me te r) and t h e Un iv er s i tyo f Michigan and Goddard ( r ad io me te r) , t h e 17 and one- half poundi n s t r u m e n t h a s as i t s o b j e c t i v e t h e s t u d y of t h e r a d i o s p e c t r aof v a r io u s c e l e s t i a l o b je c t s , i n c l u d in g our ga laxy , the Sunand t h e p l a n e t ' J u p i t e r i n low f re qu en cy ranges not r e c e f v a b l eb y Earth-based i n s t r u m e n t s . It c o n s i s t s of two independent ,but complementary systems and r e q u i r e s seven watts of powerPOP o p e r a t i o n. P r i n c i p a l I n v e s t i g a t o r i s Cr. b J , C . E r i c k so n o ft h e U n i v e r s i t y o f Maryland.

Provided by t h e U n i v e r s i t y o f

. Conzputer Engineering Experiment

The 1 3 t h expe r ime i i t ca r r i ed b y TMP-I i s a n e n g i n e e r i n gt e s t of n s p a c e c r a f t co mp uter c a l l e d t h e SDP-3. I n a d d i t i o nt o e v a l u a t i n g it:: p o t e n t t a l for fu tu r e unmanrkd s pa ce c r a f tx i s s i o n s , the SDP-3 computer w i l l b e used t o enhance t h e da tar e t u r n of t h e U n l v e r s i t y o f Minneso ta E lec t r i c and Magne t i cFie ld Exper iment , the Goddard Plasma Experiment , h e Univei*s j io f Chicago Cosmic Ray Experiment, and th e Uni ve rs i t y of C a ? i fori1i.aMedi1.m Energy P a r t i c l e s Exper imen t.

Tkie computer , weighing 12 and one-half pounds, i s agenera l -purpo se , s tored-program dev ice w i t h a o n e - l e v e l i n d l r e c ta d d r e s s i n g c a p a b i l i t y a nd o ne ha rd war e i n d e x r e g i s t e r . Itsmemory core can store f o u r t housand b i t s o f i n f o r m a t i o n i n aprogram c o n s i s t i n g of 1 6 pages of 256 words each , I t has af ive-wat ; awer requ i rement .

I n o r b i t , the computer w i l l prov ide expe r iment sequenc ingo p e r a t i on s , s e l e c t s en s or ranges and perform some experimentc a l i b r a t i o n . It w i l l a l s o stm-p data, p e rf o rm d a t a h a n d l i n gand p rocess ing t a s k s . P r i n c i p a l I n v e s t i g a t o r i s R. A . Cliffof Goddard.-more-


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T R A C K I N G GROUND SUPPORT

The I M P - I s p a c e c r a f t w i l l b e s u p p o r t f ro m g ro un d s t a t i o n so f t h e Space Track ing and Data Acquis i t ion Ne twork ( S T A D A N ) .The Range and Range Rate sysgems a t F a i r ba nks , Alaska; Rosman,N . C . ; S a n t i a go , C h i l e ; Tananar ive , Madagascar ; and Carnarvon,A u s t r a l i a w i l l p r o vi d e p r e c i s e t r a c k i n g o f t h e s p a c e cr a f t i n i t s 'e l l i p t i c a l o r b i t . A t rits f a r t h e s t po in t f r om E a r t h (some 1 2 0 , 0 0 0m i l e s ) , t h e p o s i t i o n of t h e s p a c e c r a f t w i l l be known within 30m i l e s .

The t e l e m e t r y s y s t e m s a t t h e s e s i t e s and a t F t . Myers,F l a . ; Q u i t o , Ec ua do r; and O r o r r a l V a l l e y , A u s t r a l i a , w i l lr e c e i v e s p a c e c r a f t s i g n a l s a nd r e l a y them a lm os t im m e d ia te ly v i awide b an d c o mm un ic at io n c i r c u i t s t o t h e c o n t r o l c e n t e r a t Goddard.A t t h e c o n t r o l c e n t e r t h e data w i l l b e a na ly s e d a ndappropriate commands w i l l b e g e n e r a te d a nd i s s u e d t o t h e s pa ce -c r a f t v i a t h e STADAN remote s i t e s . These STADAN s i t e s a l s os u p p o r t t h e Computer Engineer ing Experiment b y i s s u i n g t h e p ro -p e r i n s t r u c t i o n s t o t h e c o m pu t er s s memory.I n a d d i t io n t o t h i s r e a l t i m e s u p p o r t, t h e i n f o rm a t i o np r o ce s si n g d i v i s i o n w i l l p r o c e s s t h e s c i e n t i f i c da ta be inga c qu i r e d a nd f o r wa r d i t t o t h e p r i n c i p a l i n v e s t i g a t o r .A l l t h e s e g r ou nd f a c i l i t i e s a r e managed f o r N A S A ' s O f f i c eof T rack in g and Data A c q u i s i t i o n by t h e Track ing and Data SystemsD i r e c t o r a t e a t Goddard.

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DELTA LAUNCH VEHICLEThe m os t p r e c i s e and dem and in g f l i g h t b r a j e c t o r y i n

11 y ea rs of o r b i t a l f l l g h t f o r t h e Del ta r o c k e t f a c e s D e l ta# 8 3 when i t l i f t s o f f Cape Kennedy w i t h t h e IMP-I,I t must b e l aunched wi th in a 10-minute per iod, i tr e q u i r e s a second s t age r e - s t a r t o v e r Au s t r a l i a so m e 53 minutesa f t e r l i f t - o f f an d, f i n a l l y , when t h e t h i r d s t a g e f i r e s 56minutes a f t e r l aunch ing , i t s t r a j e c t o r y m ust b e as a c c u r a t eas a s k i l l e d. marksman's.A l l of t h i s i s necessa ry because t h e s a t e l l i t e ' s rendezvousp o i n t i s a keyhQle i n s r a c e f r o m where expe r iment s aboa rd IMPcan make s c i e n t i f i c o b s e r v a t i o n s when t h e Sun i s a t a s p e c i f i ca n g le t o t h e s p a ce c ra f t o r b i t .The c ig ar -s ha pe d o r b i t s c i e n t i s t s a re s h o o t i n g f o r r a n g e sbetween 145 s t a t u t e m i l e s ( p e r i g e e ) a n d 1 2 1 , 0 0 0 s t a t u t e m i 1 e S(apogee). Because of t h i s e lo n ga te d o r b i t , i t w i l l t a k e t h es p a c e c r a f t a b o u t 93 h o ur s f o r on e E a r t h o r b i t . The i n c l i n a t i o nt o t h e Equator w i l l b e 29 d e g r e e s .A s I M P - I n e a r s a po ge e ( f a r t h e s t m os t p o i n t f r om E a r t h )

t h e s a t e l l i t e l s sp ee ds s lo ws down t o 865 mph. As i t heads backtoward E a r t h t h e speed g ra du a l l y in c r ea se s . When i t swingst hr ou gh p e r ig e e ( c l o s e s t p o i n t t o E a r t h ) t h e s p e e d a c c e l e r a t e st o 24,175 mph and t h e s a t e l l i t e -s t r e a k s-___-- b ac k o u t i n t o s p a ce l i k ea n as t ro n om ic a l r o l l e r c o a s t e r .For a f l i g h t be tween March 1 2 and 1 4 , t h e launch windowopens a t 11:15 a . m . a n d c l o s e s a t ll:25 a,m. The window a f t e rMarch 14 i s as f o l l o w s :

OpensMarcQ 15 11:lO am E S TI

Closes11:20 am EST

March 16. 11:05 a m EST ll:l5 am ESTMarch 17. lot30 a m EST 10:40 am ESTr e o pe n s i n a b ou t o n e week f o r a bo ut a f i v e day p e r i o d .If t h e f l i g h t s h o u ld s l i p beyond March 1 7 , the window

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-18-There are s e v e r a l " f i r s t s " f o r Del t a #83.e It w i l l be t h e f i r s t r o c k e t w i t h s i x s o l i d b o o s te r s to

b e launched from Cape Kennedy. (Three w i l l i g n i t e on t h e pada nd t h r e e when t h e b o o s t e r i s about 7,500 f e e t above t h e LaunchComplex 1 7 . )I t w i l l b e t h e f i r s t t h r e e - s t a g e c o n f i g u r a t i o n to haves i x s t ra p -o n b o o s t e r s .

. It w i l l b e t h e f i r s t t h r e e - s t a g e c o n f i g u r a t i o n w i t hr e s t a r t c a p a b i l i t y .o r b i t f o r Delta i n 83 a t t e m p t s .If t h e f l i g h t i s s u c c e s s f u l , i t w i l l mark t h e 7 7 th s u c c e s s f u l

Del ta i s managed f o r NASA's Off ice o f Space Sc ience andAp p l i c a t i o n s by t h e Goddard Space F l i gh t Cen te r , Greenbe l t , Md.Launch op e ra t io ns a r e conducted by t h e Kennedy S pace Ce n te r ' sUnmanned Launch Operations. The McDonnell-Douglas- -_ CorP.- , Hunting-ton Beach , C a l i f . , i s De l ta p r i m e- c o n t r a c t o r it h r e e s t a g e v e h i c l e for t h e I M P - I m i ss i o n :F.ollowing a re t h e g e n e r a l c h a r a c t e r i s t i c s of t h e

T o t a l H e i g h t : 1 0 6 f e e tT o t a l Weight : 2 2 5 ,0 0 0 poundsMaximum Diameter 8 f e e t( f i r s t s t a g e )F i r s t S t a g e Thrus t 325 ,000 pounds ( in c lu des s o l i d s )(average )

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00I 4

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22/25

- 2 0 -Launch: From Complex 17, Cape Kennedy, F l a . , Eas te r n Test Range,Launch Rocket : Thre e-sta ge Del ta M-6, w i t h s i x t h r us t - au g m e nt e rsand t h e TE-364-3 t h i r d - s t a g e motor . ' 'O r b i t : Apogee: 121,000 g t a t u t e m i l e sP e r i g e e : 145 s t a t u t e milesPer io d: About fo ur d a y sI n c l i n a t i o n : 2 9 d e g r e e sOp e r a t i n g L i f e t i m e : A t l e a s t one y e a r .S p a c e c r a f t Weight : 635 pounds, i nc lud ing 215 pounds ofexpe r iment s .Main S t r u c t u r e : Drum-shaped w i t h 1 6 s i d e s , s i xa nd o ne -h al f f e e t i n diameter . f e e t t a l l , f o u rAppendages: T w o experiment booms, 1 2 f e e t long (one w i t h l oopan tenna , one w i t h magnetometer)

Tw o A t t i t u d e C o n t r o l System Booms, f i v e f e e t long,S i x a nt en na s f o r e l e c t r i c f i e l d and rad io a s t ronomymeasurements (deployed a f t e r o r b i t i s a c h i e v e d ,four o f which a r e 150 f e e t long and two 2 0 f e e t l o n g)E i g h t r a d i o f re q u en c y a n t e n n a s

Power System: Power Supply - 48 p a n e l s o f s o l a r , . c e l l s a r r an g e di n 1 6 p a n el r i n g s o n o u t e r s u r f a c e of s p a c e c r a f tt o power t h e sp ac ec ra f t and charge a 12-poundpackage of s i lver-cadmium b a t t e r i e s , Powerrequ i rement : 1 1 0 w a t t s .Communications and Data-Handling Sys tem:

T e l e m e t r y : ' Pulsed-Code Modulation (P C M ) o p e r a t i n g a t137.170 MHz ,A n a l o g t r a n s m i t t e r o p e r a t i n g a t 136.17U'MHg

Encoder and D i g i t a l Data Pr oce ss or : Pulsed, -code modula t ionw i t h d i g i t a l data s t o r a g e c a p a b i l i t y o f 500s e p a r a t e d a t a c o u n t e r sTracklng and Data A c q u is i t io n S t a t i o n : S t a t i o n s of t h eworld-wide Space Tracking and Data A c q u i s i t i o nNetwork ( S T A D A N ) o p e r a t e d by Goddard Space P l J . g h tCente r

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IMP- I PROJECT OFFICIALS AND CONTRACTORS

NASA Headquar te r sM r . Frank Gaetano - Program ManagerD r . E . Schmer l ing - P r o g r a m S c i e n t i s tM r . I . T . G i l l a m I V - Delta Program ManagerRober t S tephens - Network Engineer ing, OTDAJames C . Bavely - Network Opera t ions , OTDA

Goddard Space F l ig h t Cente rM r . P a u l B u t l e r - Pro jec t ManagerD r . Frank B . McDonald - P r oJ e ct S c i e n t i s tM r . Jeremiah J. Madden - As s i s t a n t P r o j e c t M a na ge rM r . C u r t i s M . Stout - T r a c k i n g S c i e n t i s tM r . John J. Braham - Sp ace cr a f t ManagerM r . W i l l i a m W . Conant - Experiment ManagerM r . Stephen J . Paddack ' --,.. P r o j e c t O p e ra t io n s D i r e c t o rNre Theodore C . Goldsmith - Elec t ron ic Sys tems ManagerM r . W i l l i a m S. Logan, J r . - Mech anical Systems ManagerM r . Thomas C . Moore - Track ing and Data Systems ManagerM r . W i l l i a m R . S c h i n d l e r - De l t a P r o j e c t M a na ge rM r . George D . Baker - Del ta / IMP-I Coord ina tor

Kennedy S pac e Ce nt erD r . Kurt H. Debus - D i r e c t o rMr. John J . Nei lnn - Director , Unmanned Launch Operation ( U L O )

C o n t r a c t o r sMcDonnell-Douglas As tr on au ti cs Co. , Huntington Beach, C a l i f , ,Del ta Rocke t EMR - Aerospace Sc iences , Col lege P a r k , Md., a s s i s t e di n S/C s ys te m s i n t e g r a t i o n and e n vi r o nm e n ta l t e s t i n g .

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I M P - I EXPERIMENTS AND INVESTIGATORS

1. Cssmic Ray Experiment: D r . Frank B . McDonald,Pr&n-cc.al I n v e s t i g a t o r , God dar d Spa ce F l i g h t C e n te r ; a ndc o i n v e s t i g a t o r s , Dr, Tycho von Rosenb inge , N at io n al Academyof Sc i ence Fe l low, and D r . Bonnard Teegarden, Goddard SpaceF l i g h t C e n t e r2 . G a l a c t i c a n d Solar P a r t i c l e C om po si ti on a nd Sp e c t r aExperiment: D r . J . A . Simpson , Univ e rs i ty o f Ch icago, Pr in c i -p a l I n v e s t i g a t o r ; and c o in v e s t i g a to r s , D r . M . Garcia-Munoz,S . V e r m a , and D r . J , Hsieh, Un ive rs i t ? o f Chicago.3 . Low-Enernv Prot on and El ec t r on Dif fer ent ia l -En era v1, Frank,_ P r i n c i p a l. I n v e s t i g a t o r ,

4 . E n e r g e t i c P a r t i c l e E xp er im en t: D r . Kinsey Anderson,P r i n c i p a l I n v e s t i g a t o r , U n i v e r s it y o f C a l i f o r n i a ( B e r k e l e y ) .5 . Sola r . Prot on Moni tor ing Exper iment : D r . Car l Bostrom,P r i n c i p a l-I-._ I n v e s t i g a t o r , Jo hn s Hop ki ns Un i v e r s i t y App li ed Ph y s i c sL a b o r a t o r y ; ' a n d c o i n v e s t i g a t o r s , D r . D . S . B e a l l , APL, and

D r , Donald J . W i l l i a m s , N O A A , Boulder, Colorado.6. So la r and Di , s t an t Magne tosphe re E lec t ro ns Experiment :D r . Thomas L . C l i n e , P r i n c i p a l I n v e s t i g a t o r , ' Goddard Sp ace F l i g h tC e n te r , an d c o i n v e s t i g a t o r , Dr. K . Br uns te l n , Bendix Corp.,

Columbia, Md.7 . Plasma Experiment: D r . Kei th W e O g i l v i e , P r i n c i p a lI n v e s t i g a t o r , Goddard Spa ce F l i g h t C e n t e r ,8 . Los Alarnos-Sandia P l a s m a Experiment: Dr, S . J. B a m e ,P r i n c i p a l I n v e s t i g a t o r , U n i v e r s i t y o f C a l i f o r n i a (Los A ng el es )a n d c o i n v e s t i g a t o r , D r . J. R . Asbr idge , Los Alamos S c i e n t i f i cLabora to ry o f t h e Un iv e r s i t y o f C a l i f o r n i a .9 . D i r e c t C u rr e nt E l e c t r i c F i e l d s E xp er im en t: D r .Thomas L. Aggson, P r i n c i p a l I n v e s t i g a t o r , Goddard Sp ac e F l i g h tC e n te r ; an d c o i n v e s t f g a t o r , D r . James P . Heppner, GoddardSpa ce F l i g h t C e n t e r .1 0 . A l t e r n a t i n g C u r r en t E l e c t r i c a n d M ag ne ti c F i e l dExper iment : D r , Doanld G u r n e t t , P r i n c i p a l I n v e s t i g a t o r , Uni-v e r s t i y of Iowa; a n d c o p n v e s t i g a t o r s , D r . P , J , Kel log, Univer-s l t y of Minnesota; Dr. Thomas L. Aggson and D r . James P.Heppner Goddard Sp ace E'l iy,ht Center

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11. Magnetic-Field Experiment: D r . Norman F. Ness,Pr i n c i p a l I n v e s t i g a t o r , Goddard Spa ce F l i g h t C e n t e r ; a nd c o in -v e s t i g a t o r , R . J. Seek, Goddard Space F l i g ht Cente r .1 2 . Radio Astronomy Experiment: Pr of es so r W . C . E r i c k so n ,P r i n c i p a l I n v e s t i g a t o r , U n i v e r s i t y o f M ar yl an d; and c o i n v e s t i -g a t o r s , P r o f e s s o r F. T . Haddock, Universi ty of Michigan, and

D r . Rober t G . Ston e , Goddard Space F l i gh t Center .13. SDP-3 Computer En gi ne er in g Exp eri men t: RodgerA . C l i f f Pr i n c i p a l I n v e s t i g a t o r , Goddard Spa ce Flight C e n t e r ,

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