international sun earth explorers isee press kit

8/8/2019 International Sun Earth Explorers ISEE Press Kit

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NASA News--National Aeronautics andSpace AdministrationWashington.D C 20546AC 202 755-8370

For Release IMMEDIATE

PressKitREL EAS E NO: 77-213

Project International SunEarth Explorers(ISEE)

ContentsGENERAL RELEASE................................... 1-10ISEE-A, B AND C SCIENTIFIC INSTRUMENTS............ 11-13MISSION DESCRIPTION............................... 14-18IN TE RN AT IO NAL MA GN ET OS PH ERE STUDY SUPPORT......... 18SCIENTIFIC PAYLOAD DESCRIPTION..................... 19-23DELTA LAUNCH VEHICLE (2914).......... ............. 24INTERNATIONAL SUN-EARTH EXPLORERS (ISEE-A & B) . 25(ChartLAUNCH OPERATIONS................................. 26ISEE-A AND B PROGRAM MANAGEMENT................... 26-27LAUNCH SEQUENCE FOR ISEE-A AND B.. . . . . . . . . . . . . . . . . 28ISEE-A AND B TEAM.................................. 29-31

Mailed:October 13, 1977


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C ewsNational Aeronautics andSpace Ad ministrationWashington. D C 20546AC 202 755-8370

N i c h o l a s P a n a g a k o sH e a d q u a r t e r s , W a s h i n g t o n , D.C.(Phone: 2 0 2 /7 55- 3 6

Fc JrReleaseI M M E D I A T E

Joseph McRober tsGoddard Space F l i g h t C e n t e r , G r e e n b e l t , M d .(Phone: 301/982-4955)

RELEASE NO : 77-213

MOTHER-DAUGHTER SATELLITES SET F O R LAUNCH

Two s p a c e c r a f t w i l l b e l a u n c h e d by a s i n g l e roc ke t t h i smonth a s p a r t of a c o o p e r a t i v e program by NASA and The Euro-pea n Spa ce Agency (ESA) t o g a i n a b e t t e r u n d e r s t a n d i n g o fhow t h e Sun c o n t r o l s t h e E a r t h ' s n e a r s p a ce en vi ro nm e nt .

C a l l e d I n t e r n a t i o n a l S un E a r t h E x p l o r e r s , t h e mother-and-daugh te r s a t e l l i t e s w i l l b e l a u n c h e d a b o u t Oct. 1 9 fromKennedy Sp ac e C e n t e r , F l a . , i n t o l o o p i n g t r a j e c t o r i e s a roundt h e E a r t h , r a n g in g i n d i s t a n c e f r o m 1 4 0 , 0 0 0 k i l o m e t e r s( 8 7 , 0 0 0 m i l e s ) t o 280 km ( 1 7 4 m i . ) .

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The mission involves 117 scientific investigators, 35universities and 10 nations.

Circling our planet for three years or more, theinstrument-laden spacecraft are expected to provide detaileddata on how solar wind particles control the boundariesbetween Earth space and interplanetary space. This willlead to a better understanding of a variety of solar-terrestrial phenomena, includinq weather and climate, energyproduction and ozone depletion in the atmosphere.

ISEE-A, managed by NASA, and B, managed by ESA (to bedesignated ISEE-1 and ISEE-2 after orbital insertion), arethe first set of spacecraft designed to be used together toinvestigate Earth's immediate space environment.

Shortly after third stage burnout, when the two space-craft have attained the reauired trajectory, they will beseparated from each other but will remain in the same orbit.The separation distance between ISEE-1 and ISEE-2 will bevaried by the controllers between a few hundred to a fewthousand kilometers during the lifetime of the mission.

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For reasons of energy conservation, the smaller space-craft, ISEE-2, weighing 158 kilograms ( 3 4 8 pounds), will bethe maneuverable spacecraft. The orbit of I S E E - 1 will notbe changed. Initially, however, both spacecraf% will under-go attitude maneuvers so that both point to the same placein space.

All maneuvers will he conducted by a NASA/ESA team atNASA'S Goddard Space Flight Center, Greenbelt, Md.

The use of two spacecraft, separated by a variabledistance, will allow scientists to study the boundaries innear-Earth space and the nature of their fluctuations. Theseinclude the plasma pause -- the position at which there is adramatic drop in the density of the magnetosphere -- the mag-netic envelope which surrounds the Earth; the magnetopause,where the magnetic field of the Earth meets that of the solarwind; the bow shock, a sort of bow wave created by the motionof the solar wind past the Earth, and several less obviousfeatures of the Earth's maqnetic tail.

Measurements by instruments on a pair of spacecraftwill permit ambiguities associated with the motion c f theseboundaries to be resolved.

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In the past, a large number of phenomena measured bysingle instruments on spacecraft were not clearly under-stood. For example, did the sudden increase in energeticparticles noted from measurements by one spacecraft comefrom an eruption on the surface of the Sun, perhaps a solarflare, or did it come from some other source? Perhaps theparticles were suddenly released from the Earth's radiationb e l t s or were bounced back from t h e bow shock f r o n t t h a textends hundreds of thousands of kilometers out from Earth.With two spacecraft at different points on a similar tra-jectory with similar instrumentation, time and space aspectsassociated with such problems can be solved.

Even greater scientific returns will be possible whena third spacecraft, ISEE-C, is launched by NASA next summerto what is called the libration point -- about 1.5 millionkm (932,055 million mi.) from Earth toward the Sun -- wherethe satellite will remain with only minor onboard qas adjust-ments. At that point in space, the forces of gravity andthe dynamic force exert an equal pull.

ISEE-C (to be called ISEE-3 in heliocentric orbit) willobtain nearly continuous data on the fluctuating solar wind,and on special solar phenomena, such as solar flares, aboutan hour before the solar particles flow past ISE E -1 and 2 inEarth orbit.

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I n c e r t a i n i n s t a n c e s , t h i s w i l l g i v e s c i e n t i s t s ont h e g r o u n d t i m e t o m a k e i n p u t s t o onboard i n s t r u m e n t a t i o non t h e mo th er -d au gh te r s p a c e c r a f t t o l oo k f o r c o r r e l a t i n gphenomena. A t t h e s a m e t i m e , s o un d in g r o c k e t s c o u l d b ef i r e d from an y g l o b a l l o c a t i o n on c u e f r o m Goddard C e n t e ra t d i f f e r e n t l a un ch a r e a s a ro un d t h e wo rl d t o i n v e s t i g a t eo t h e r a s p e c t s o f o n r u s h in g s o l a r wind. A s p a r t o f a programc a l l e d t h e I n t e r n a t i o n a l M a g ne t os p he r ic S tu d y ( IM S), gr ou nds t a t i o n s , s ou nd in g r o c k e t s , b a l l o o n s , a i r c r a f t and s a t e l l i t e s ,i n c l u d i n g t h e I S E E s p a c e c r a f t , w i l l look a t t h e same phe-nomenon s i m u l t a n e o u s ly from d i f f e r e n t p a r t s o f t h e E z r t h ,i n c l u d i n g p o l a r a r e a s a nd s pa ce .

I S E E c o o r d i n a t i o n i s d e s ig n e d t o f i t i n t o t h e I M S pro-gram, which i s a w or ld -w id e t h r e e - y e a r i n v e s t i g a t i o n b eg uni n 1 9 7 6 . ISEE-A, B and C a r e m ajo r c o n t r i b u t i o n s t o t h e I M Sb y t h e U.S. and Europe. D a ta exchange o f f i c e s have beene s t a b l i s h e d i n Meudon, France , and B oulde r , Colo . Meanwhile,a s o p h i s t i c a t e d S a t e l l - i t e S i t u a t i o n C e nt er ( S S C ) a t Goddardw i l l c a l c u l a t e s a t e l l i t e o r b i t s w hich w i l l h e p u b l i s h e dt h r ou g h t h e B ou ld er o f f i c e . The p u b l i s h e d SSC o r h i t s a r ed es ig ne d f o r c o r r e l a t i o n w i t h t h e v a r i o u s I M S s y s te m s t oi n d i c a t e when s p a c e c r a f t d a t a a re l i k e l y t o b e e s p e c i a l l yf r u i t f u l .

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Although numerous other spacecraft have been probingthe magnetosphere since the early 1960s, the ISEE satellitescarry instrumentation 10 times more sensitive than previouslyflown. Five years ago, the ISEE series couldn't be flownsimply because the required technoloqv did not exist. Asa result, much fine detail information essential to under-standing the range of Sun-Earth phenomena, the entire environ-mental system of Earth, and the interactions between the twois now available with the ISEE spacecraft for the first time.

The earlier missions have shown that our space environ-ment is very dynamic and exhibits changes more drastic thanthe weather patterns seen near the ground. It is preciselythese changes which need to be studied, using instrumentsdesigned to operate in close coordination, to establish thecomplex interrelationships which control our "space weather."

ISEE-A is a 16-sided cylindrical body measuring approx-imately 1 . 7 3 meters (5 feet 8 inches) across and 1.61 m ( 5ft. 4 in.) high. Its main body consists of an 84-centimeter(1 ft. 9 in.) conical center tube, an aluminum honeycombequipment shelf supported b y eiqht struts. The lower end ofthe center tube mates with the launch vehicle and the upperend with the ISEE-B.

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Certain exposed areas o f the ISEE-A and C spacecraftare coated with a conductive green paint developed at Goddardas passive electrical as well as thermal protection to keepthe voltage buildup to no more than one totwo volts, even asthey pass through the radiation belts.

ISEE-B is a circular cylinder, with a diameter of 1.27 m( 4 ft.) and a height of 1.14 m ( 3 1/2 ft.). Solar cells aremounted on three detachable curved panels. An aluminum honey-comb platform supported by eight struts and center tube arethe main load-carrying portions.

NASA is responsible for the A and C spacecraft, Deltalaunch vehicle, tracking and data acquisition and data pro-cessing. E S A is responsible for the ISEE-B spacecraft andits operation.

Goddard will provide orbital computation, attitudedetermination and spacecraft control support to the ISEEmissions during the planned three-year lifetime of thesatellites. ESA, in coordination with Goddard, is respon-sible for preparing, testing and operating the ISEE-B space-craft and software for maneuver determination and computation.

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There are a total of 117 investigators on all threespacecraft representing 35 university, government and indus-trial organizations in 10 countries.

ISEE-A is a Goddard Center designed spacecraft built,fabricated and tested at Goddard with all its componentseither made at Goddard or supplied by industries or univer-sities. ISEE-B is an ESA-European Space Technology Center(ESA-ESTEC) satellite whose design was determined throughcompetitive concepts.

The STAR consortium of 10 countries supervised con-struction under contract to ESA. STAR consists of industriesin Belgium, Denmark, France, Spain, Germany, Italy, Nether-lands, Sweden, Switzerland and the United Kingdom. DornierSystems in Frederickshaven, Germany, heads the contractorteam.

Goddard directs the Delta rocket program for NASA'sOffice of Space Flight and McDonnell Douglas AstronauticsCo., Huntington Beach, Calif., is prime contractor.

Estimated cost of the two spacecraft and the scientificinstrumentation is about $ 4 5 million, exclusive of launch andtracking and data acquisition costs.

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The la un ch window ope ns O c t . 1 2 , 1 9 7 7 , a nd c l o s e sOct. 2 7 , 1977. T h e r e is a 2 0- mi nu te o p p o r t u n i t y i n t h ee a r l y p a r t of t h e l a un ch window each d ay s t a r t i n g b etw eena b o u t 1 0 : O O a.m. ED T and 10:30 a .m. EDT, d e p en d i ng o n t h eday. The l a u n c h w indo w b e g in s t o n a r r o w on O c t . 20 and isr e d u c e d t o f i v e m i nu te s on Oct. 29.

(END O F GENERAL RE LEA SE. BACKGROUND I N F O R M A T I O N FOLLOWS. )

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ISEE-A, -B and -C SCIFNTIFIC INSTRUMENTSI SEE-AInstrument

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*Fast PlasmaPrincipal Investigator AffiliationS. J. Bame Los Alamos Scientific Laborator

*Low Energy Proton and Electron L. A. Frank*Fluxgate Magnetometer C. T. Russell

*Plasma Waves*Plasma Density

D. A. GurnettC. C. Harvey

*Energetic Electrons and Protons D. J. Williams

*Electrons and Protons K. A. AndersonD.C. Electric Field J. P. HeppnerIon Composition R. D. SharpVLF Wave Propagation R.' A. HelliwellFast Electrons K. W. OgilvieLow Energy Cosmic Ray D. HovestadtQuasi-Static Electric Fields F. S. Mozer

*The instruments of A and B that are interrelated.

University of IowaUniversity of California,Los AngelesIJniversity of IowaParis ObservatoryNational Oceanic and AtmospheriAdministrationUniversity of California, BerkeGoddard Space Flight CenterLockheed Electronics Co.Stanford UniversityGoddard Space Flight CenterMax Planck InstituteIJniversity of California

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ISEE-BIn e n Principal Investigator*Fast Plasma G . Paschmann*Low Energy Proton and Electron L. A. Frank*Fluxgate Magnetometer C. T. Russell

*Plasma Waves D. A. Gurnett*Plasma Density C. C. Harvey*Energetic Electrons and Protons E. Keppler*Electrons and Protons K. A. AndersonSolar Wind Ion Measurements G . Moreno

ISEE-CSolar Wind PlasmaMagnetometer

Low Energy Cosmic RayMedium Energy Cosmic RayHigh Energy Cosmic RayPlasma Waves

S. J . BameE. J. SmithD. HovestacltT. von Rosenvinge1. H. HeckmanF. L. Scarf

AffiliationMax Planck InstituteUniversity of IowaUniversity of California,Los AngelesUniversity of IowaParis ObservatoryMax Planck InstituteUniversity of California, BerkeLaboratorio Plasma Spazio,Frascati, Italy

L o s Alamos Scientific LaboratoJet Propulsion Laboratory

Max Planck InstituteGoddard Space Flight CenterUniversity of CaliforniaT W

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ISEE-c (cont'd.InstrumentCosmic Ray ElectronsProtons

X-Rays and ElectronsRadio MappingPlasma Composition

, High Energy Cosmic Ray

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Ground Based Solar Studies

Principal InvestigatorP . MeyerL. D. de Feiter

K. A. AndersonJ. L. SteinbergK. W. OgilvieE. C. StoneJ. M. Wilcox

AffiliationUniversity of ChicagoSpace Research Laboratories,UtrechtUniversity of CaliforniaMeudon ObservatoryGoddard Space Flight CenterCalifornia Institute ofTechnologyStanford University

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-14-MISSION D E S C R I P T I O N

The ISEE-A and B spacecraft are the first set of space-craft designed to be used together to investigate the physicalstructures surrounding the Earth, It is hoped that thesespacecraft will be able to resolve questions related to thedetailed structure of the magnetosphere, magnetopause andshock front that cannot be answered by a single spacecraft.The orbit was selected to nearly maximize the number of bowshock crossings. The separation distance of the two spacecraftis intended to have the spacecraft separation be 100 kilometers(62 miles) at 15 Earth radii as the starting position and letthe distance drift to 2 or 3 thousand km (1,240 to 1,865 mi.)before restoring it. The spacecraft are much closer at apogeeand very far apart at perigee using this control point.Solar Wind and Upstream Phenomena

The elemental and isotopic ahundances in the solar windshow strong time variations. These could result from diffusionprocesses in the solar photosphere-corona boundary, from dynamicfriction, from wave-particle interactions or from separationprocesses that depend primarily on ionization and energv.Energetic solar protons and electrons are observed in theinterplanetary medium during solar events. Investigation ofthese is aimed at discovering how they originate in the Sunand how they are affected by the medium in which they travel.Care is needed to differentiate between source and propagationeffects, and in this respect the observations of the helio-centric ISEE-C spacecraft wi.11 be very useful.It is known that the presence of the Earth has a disturbingeffect in interplanetary space in front of the bow shock andfor quite large distances uDstream. By using ISEE-A and B itshould be possible to look for the types of particles and wavesthat are reflected from the bow shock. A study can a l s o bemade of the effect of the backstreaminq protons and electronson the solar wind itself.A great variety of these interplanetary discontinuitiesexist, traveling with characteristic speeds of the order ofhundreds of kilometers per second, making large separationsnecessary for good observation. Simultaneous "mother" and

"daughter" measurements will be able to distinguish shock-accelerated from solar-accelerated protons. ISEE-A and Rspacecraft carry electron density measuring equipment whichshould be able to resolve density variations in shock structuresand discontinuities.

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Neutral magnetic and current sheets in the solar windwill be studied as they sweep past ISEE-A and B. The ISEEmission will also be able to distinguish solar co-rotatingfeatures from others.A major part of the ISEE mission is the study of wave-particle interactions. Because of the variability of thesolar wind, the characteristic frequencies of the plasma are

also highly variable. Using two spacecraft, it should bepossible to remove some of the ambiguities.The complexity and variability of the solar wind velo-cities, composition and densities together with the presenceof particles and waves backstreaming from the bow shock en-sures that many known and unknown wave-particle interactionswill take place in the near-Earth interplanetary medium, The

I S E E twin spacecraft investigation is expected to unravel someof the basic processes.The Bow Shock

This feature of the Earth's environment has been knownto exist since 1963 when it was first seen by IMP-1 but iden-tification of even the dominant mechanisms has not yet beenaccomplished. A basic problem here is that the bow shockapparently moves back and forth with an amplitude of aboutone Earth radius and the velocity of this movement seems tovary between 10 and 200 km per second (6 to 125 mi. per second).Both ions and electrons are heated in the shock and the mecha-nism is thought to be a retardation and heating by some formof electrostatic turbulence.Detections of regions of this size by a single-pointmeasuring system in the fast-moving bow shock is extremelydifficult. Assuming shock speeds of about 100 km/s (62 mi./s),simultaneous measurements at two points about 100 km (62 mi.)apart by instruments with reasonable time resolution should beable to detect the larger scale features,The bow shock may also be the source of electron spikesseen in the magnetosheath and movement of both ions and elec-trons towards the Sun upstream of the shock. The mechanismfor acceleration and reflection of these particles is notunderstood at present and in-particular the transient nature

of the observations is baffling.

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Because of space-time ambiguities, the extent and wave-lengths of these phenomena have not been determined and sothey too are suitable objects for a twin spacecraft study.These spacecraft must spend sufficient time outside the bow shockregion for a wide range of solar wind effects to be encounteredto evaluate their influence on the upstream phenomena and thebow shock.The Magnetosheath

Magnetic field fluctuations which occur in different modesand have many different frequencies characterize the Earth'smagnetosheath. This complex situation is further complicatedbecause the plasma frame is convecting past the spacecraft ata velocity which is influenced by the solar wind and the posi-tion of the spacecraft in the magnetosheath.The dominant mechanisms by which the turbulences in thisregion are created have not yet been clearly identified andit is accepted that techniques of correlating field and plasmameasurements on a single spacecraft are not adequate for ananalysis of this structure. Measurements by ISEE-A and B willbe able to identify propagation velocities which should clarifythe picture considerably.

The MaanetoDauseFor many years the nature of the magnetopause boundaryhas provided a motive for magnetospheric research. fleverthe-less, the answers to most of the key questions are still un-

clear: such problems as the way in which mass and energy aretransferred across the boundary, how reconnection works or themechanism of viscous interaction have not been solved. Isthe oscillation of this boundary a simple "breathing" of themagnetosphere or is it the result of the solar wind blowingpast?Theories of reconnection and viscuous interaction areincomplete because the treatment of viscuous interaction needsmore detail of the magnetosheath magnetic fields than is avail-able and reconnection studies have not been ahle to demonstratethat the process works over a sufficient range of interplanetaryfield angles because of lack of magnetopause information.Again the problem is associated with the movement of theboundary and with the question of whether the features observedare propagating or not. It is hoped that identification ofmotions by the ISEE mission will make a large contribution toour understanding of this boundary.

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The Plasma Sheet and the TailThe ISEE mission is uniquely fitted to study the dynamicsof particle acceleration in the tail. Qualitative measurementsof the flow of plasma and energetic particles up and down the

tail will be made and compared with incoming solar wind para-meters as observed by the heliocentric ISEE-C spacecraft.Single satellite magnetic measurements imply that a thinneutral sheet is embedded in the much thicker plasma sheet.Detection of the neutral sheet is difficult since the fieldstrengths are very weak and there is considerable upward anddownward movement of this region, with velocities of between10 and 100 km/s ( 6 to 62 mi./s). Twin spacecraft measurementsshould be able to identify the structural features of the innerplasma sheet by separating out the velocity.

Ring Current and PlasmasphereThe ISEE-A and B spacecraft will be able to provide thefirst comprehensive observations of the total ring currentenergy spectrum, pitch angle and spatial distributions duringquiet times, They will also allow observation of the driftinto this region of the low-energy (tens of keV) protons duringthe main phase of magnetic storms. It is hoped that the wayin which these particles filter around the Earth to form asymmetric ring current will be discovered.

Maqnetospheric SubstormsThe understanding of the suhstorm Phenomenon is one of

the key steps to the understanding of the dynamics of themagnetosphere, However, substorms in themselves are verycomplex. Violent rearrangements of magnetic fields during thesubstorm expansion phase associated with strong electric induc-tion fields have drastic effects on plasma flow, charged par-ticles and on the ionosphere.It seems probable that the energy needed to drive theseprocesses is extracted from the solar wind by some mechanismin the tail, but this mechanism has not been identified, Itis not known how or why substorms are trigqered. Althoughparticles are accelerated, the region and source of thisacceleration have not been discovered. Because geomagnetic

substorms involve a large part of the magnetosphere, correlatedglobal measurements will be necessary for any attempt atunderstanding.

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These measurements must include, as well as ISEE-A and Bin the tail, inner magnetospheric observations by G E O S andATS-6, upstream solar wind measurements by ISEE-C, suitablerocket flights to investigate the ionosphere with other world-wide high-latitude ground-based measurements and assistancefrom other spacecraft.

INTERNATIONAL MAGNETOSPHERE S T U D Y SUPPORT

The ISEE project, from its inception, has been designatedto support the International Magnetospheric Study (IMS). TheIMS is an international cooperative enterprise with a principalscientific objective of achieving a comprehensive, quantitativeunderstanding of key processes associated with energy, mass andmomentum transfer from the solar wind to the magnetosphere andatmosphere. IMS is the first attempt to use a systems approachto Sun-Earth study on a large scale,

The system approach in the IMS case is a conscious plan toaccumulate data simultaneously so that correlative studies canbe made on a worldwide and outer space basis. T h i s requiresthat spacecraft be located in orbits advantageous to earthboundobservations and that prediction of spacecraft positions beavailable to make sure that ground base data is collected atthe appropriate time.

Sounding rocket campaigns will be planned to coincide withspacecraft positions and, in some cases, spacecraft data willbe used to determine sounding rocket launch times.T h c ISEE-C spacecraft, from its vantage point a millionmiles in front of the Earth, can measure the parameters ofthe solar wind unperturbed by the Earth's presence and can doit one hour in advance of that portion of the solar wind'sarrival at the Earth's physical boundaries, These data can becompared to the Earth's reaction to this portion of the solarwind as it impinges on the bow sIngck and the magnetosphere.In short, ISEE-C measures the solar input function; ISEE-Aand B measure its impact on the magnetic field about the Earth;and the ground-based magnetometers measure the resultant changesat the Earth's surface. It is hoped that by obtaining this and

similar spacecraft and sounding rocket data over large spaceand time variations, better models can be established for thebehavior of the Earth's fields and radiation belts.

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SCIENTIFIC PAYLOAD DESCRIPTION

Fast Plasma (ISEE-A and B )Dr. S. ,l. Bame, L o s Alamos Laboratories, Los Alamos, N.M.,(ISEE-A) and Dr. G. Paschmann, Max Planck Institute, WestGermany (ISEE-B)L o s Alamos Scientific Laboratories supplies the sensorportion of the ISEE-A and B instruments and Xax Planck Institutesupplies the electronics for both instruments.Determinations of electron and ion velocity distributionsin one-, two- and three-dimensional form will be obtained fromboth ISEE-A and B spacecraft. These determinations are madeusing identical 90 degree spherical section electrostatic two-dimensional and three-dimensional analyzers. The A experiment

will also include a solar wind ion 150 degree spherical sectionanalyzer.Low-Energy Protons and Electrons (ISEE-A and B)

L. A. Frank, University of Iowa, Iowa City.An improved low energy proton and electron differentialenergy analyzer (LEPEDEA) each on the A and B satellites willbe employed. These are in the shape of a quarter sphere andconsist of three of these quadrispherical concentric plates.Fourteen channel multipliers are used so that the instrumentcan measure angular distributions. Seven multipliers are used

for protons and seven for electrons. Measurements of both canbe made simultaneously.Fluxaate Maanetometer (ISEE-A and B I

C. T. Russell, University of California, Los Angeles.Three ring core sensors in an orthogonal triad are enclosedin a flipper mechanism at the end of the maqnetometer boom. Theelectronics unit is on the main body of the spacecraft at thefoot of the boom. The magnetometer has two operating ranges of+ 8192 and +512 in each vector component. The data are digi-tized and averaged within the instrument to provide increased

resolution and to provide Nyquist filterj-nq.-

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- 20 -Plasma Waves (ISEE-A and B)

D. A. Gurnett, University of Iowa.The frequency range to be investigated is 1 Hz to 200 kHz

for electric fields and 1 Hz to 10 kHz for magnetic fields.The basic instrumentation provides a complete set of triaxialmagnetic field measurements on the A spacecraft and much simplersingle axis electric and magnetic field measurements on the Bspacecraft. Measurements on the A spacecraft are intended tocover all wave characteristics, such as wave-normal direction,polarization and Poynting flux. The single axis measurementson the B are intended to provide detailed comparisons of thefrequency spectrum and field amplztudes at the two spacecraft.Plasma Density (ISEE-A and B)

C. C. Harvey, Paris Observatory.The electron density in the vicinity of the A spacecraftwill be measured by means of a radio techniqueresonances of the ambient plasma. These resonances occur atthe plasma frequency, the upper hybrid resonance, the cyclotronfrequency and its harmonics and their study permits the deter-mination of several plasma parameters and notably the electrondensity.

to detect

Energetic Electrons and Protons (ISEE-A and B)D. J. Williams, National Oceanic and Ptmospheric Adminis-tration, Washington, D.C. (ISEE-A) and E. Keppler, Max Planck

Institute (ISEE-B)The principle of the measurements is to separate electronsand protons by a magnet, deflecting each type of particle intoone or more solid state detector telescopes where the pulseheights can be analyzed. This will be accomplished by flyingsolid state detector systems on both A and B spacecraft tomeasure detailed energy spectra and angular distributions ofprotons in the energy range 20 keV to 2 MeV and electrons inthe energy range 20 keV to 1 MeV. The NOAA Space EnvironmentLaboratory is responsible for A instrument hardware and inte-gration and the Max Planck Institute for Aeronomy is responsiblefor B instrument hardware and integration.

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Electrons and Protons (ISEE-A and B)K. A. Anderson, University of California, Berkeley.Two identical solid state detector telescopes are used,one open, and the other covered with parylene foil, The tele-scopes have a viewing cone with a half angle of 4 0 degrees,oriented at an angle of about 20 degrees with the spin axisof the spacecraft. Electrons will be measured in two energybands, 8 to 200 keV and 30 to 200 keV. Protons will also bemeasured in these energy ranges and in addition between 200and 3 8 0 keV.

Fast Electrons (ISEE-A)K. W. Ogilvie, Goddard Space Flight Center, Greenbelt, Md.Two identical instruments are mounted diametricallyopposite one another in the spacecraft, each having threeelectrostatic analyzers. The axes of each set of analyzersare mutually perpendicular and are oppositely directed tothose of the other set. Thus the net flux of electrons in agiven direction can be determined, and a good approximation

to the three dimensional velocity distribution function obtained.Two channelton electron multipliers are used on each of sixanalyzers. There are three modes of operation: solar wind7 . 4 to 4 9 4 eV; magnetosheath 19.5 to 2006 eV and maqnetotailand solar 106 to 7 0 7 7 eV.Low Energy Cosmic Ray (ISEE-A) and Gamma Ray Burst

D. Hovestadt, Max Planck Institute.The instrument consists of three sensors and associatedelectronics:0 An Ultra Low Energy nuclear charge (Z), total energy(E) and ionic charge ((1) assembly (ULEZEQ); thissensor consists of two physically separated units.0 An Ultra Low Energy Wide Angle Telescope designatedULEWAT.0 A Gamma Ray Burst detector.

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Quasi-static Electric Field (ISEE-A)F. S . Mozer, University of California.Fields are obtained from measurements of the potentialdifference between a pair of spheres, each of which is mountedon the end of a 50-meter wire boom. The measured potentialdifferences are converted to electric field components in thespacecraft frame of reference by dividing each measurement bythe sphere separation distance, after which the resulting fieldsare converted to Earth-fixed, inertial, or other frames ofreference by subtraction of the induced electric field result-ing from spacecraft motion through the magnetic field.

DC Electric F i e l d (ISEE-A)J. P. Heppner, Goddard Space Flight Center.The electric field in th e spin plane of the spacecraftis determined by measuring the difference in the floatingpotential between the conducting tip sections of two colinearwires extended perpendicular to the spin axis.Calibration checks and plasma impedance measurements canbe conducted either instantaneously or periodically by commandfunctions.

Ion Composition (ISEE-A)R. D. Sharp, Lockheed Electronics Co., Plainfield, N.J.The energetic ion mass spectrometer is a high-sensitivityhigh-resolution analyzer designed to measure the ionic composi-tion over the mass-per-unit-charge region from 1 to 138 AMU in

the energy-per-unit-charge range from zero to 17 keV. Theinstrumentation consists of two complete spectrometers. Theseare required outside the magnetosphere to provide adequateelevation angle coverage.

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VLF Wave P r o p a g a t i o n (ISEE-A)R. A. H e l l i w e l l , S t a n f o r d U n i v e r s i t y , P a l o A l t o , C a l i f .The ma in wave i n j e c t i o n d e v i c e i s th e S t a n f o r d V L F t r a n s -m i t t e r p r e s e n t l y i n o p e r a t i o n a t S i p l e S t a t i o n i n t h e A n t a r c t i c .I n r e c e n t t e s t s , s i g n a l s from t h i s t r a n s m i t t e r hav e b ee n s uc -c e s s f u l l y i n j e c t e d i n t o t h e m ag ne ti c e q u a t o r i a l p l a n e and ha veb e e n o b s e r v e d v i a s a t e l l i t e . For t h e I SEE m i s s i o n , t h e t r a n s -m i t t e r w i l l be used t o i n j e c t V L F waves th r o u g h o u t t h e m ag ne to -s p h e r e , p r o d u ci n g b o t h VL F e m is s io n s and e n e r g e t i c p a r t i c l ep i t c h a n g l e s c a t t e r i n g .n a l , a s w e l l a s a ny s t i m u l a t e d VLF e m i s s i o n s w i l l be de t ec t edo n t h e A s p a c e c r a f t b r o a d b a n d VL F r e c e i v e r p r o vi d ed b y S t a n f o r dU n i v e r s i t y .

I n th e g e n e r a l case t h e i n j e c t e d s i g -

S o l a r Wind Ions (ISEE-B)~~ ~

G. M o r e n o , L a b o r a to r io Plasma S p az io , F r a s c a t i , I t a l y .T h i s i n s t r u m e n t i s d e s i g n e d t o measure t h e f lo w d i r e c t i o n sand en er gy s p e c t r a of t h e p o s i t i v e i o n s i n t h e s o l a r wind. Twomodes of o p e r a t i o n a r e p r o v i d e d , o n e c o n c e n t r a t e s o n h i g h angu-l a r r e s o l u t i o n and the o t h e r on h i g h e n e rg y r e s o l u t i o n .main r e gi o n o f i n t e r e s t f o r t h i s i ns t ru m e nt i s outward f rom andi n c l u d i n g t h e magnetopause .

The

m o r e -

f


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DELTA LAUNCH V E H I C L E ( 2 9 1 4 )

The ISEE-A/B s p a c e c r a f t w i l l be l aun ched by at h r e e s t a g e D e l t a 2 9 1 4 l a u n ch v e h i c l e . The l a u n ch v e h i c l eh a s a n o v e r a l l l e n g t h o f a p pr o xi m at e ly 35 meters (115 f e e t )and a maxumum body diameter of 2 .4 m (7.8 f t . ) . A b r i e fd e s c r i p t i o n o f t h e v e h i c l e ' s m ajo r c h a r a c t e r i s t i c s f o ll ow s :F i r s t S t a a e

The f i r s t s t a g e i s a McDonnel l Douglas modif iedT hor b o o s t e r i n c o r p o r a t i n g n i n e s t r a p - on T h io k o l s o l i d -f u e l r o c k e t m o to r s. The b o o s t e r i s powered by a Rocket-d yn e e n g i n e u s i n g l i q u i d o xy ge n a nd l i q u i d h y d r o ca r bo np r o p e l l a n t s . The m ain e n g i n e i s g im b al -m o un te d t o p r o v i d ep i t c h an d yaw c o n t r o l fro m l i f t o f f t o m ain e n g i n e c u t o f f( M E C O ) .

Second S tageT h e s e c o n d s t a g e i s powered by a TRW l i q u i d f u e l ,p r e ss u r e -f e d e n gi n e t h a t a l s o i s gimbal-mounted t o p r o -v i d e p i t c h a nd yaw c o n t r o l t h ro u g h t h e s ec o nd s t a g e b u rn .A n i t r o g e n g as s y s t e m u s e s e i g h t f i x e d n o zz l es f o r r o l lc o n t r o l d u r i n g powered a nd c o a s t f l i g h t , as w e l l as p i t c ha nd yaw c o n t r o l d u r i n g c o a s t a nd a f t e r s ec o n d s t a g e c u t o f f(SECO). Two f i x e d n o z z l e s , f e d by t h e p r o p e l l a n t t a n kh e li um p r e s s u r i z a t i o n s ys te m, p r o vi d e r e t r o t h r u s t a f t e rt h i r d s t a g e s e pa r a t i o n .

T h i r d S t a s eThe t h i r d s t a g e i s t h e TE-364-4 s p i n - s t a b i l i z e d ,s o l i d p r o p e l l a n t T h io ko l m otor , I t i s s ec ur ed i n t h e s p i nt a b l e mounted t o t h e se co nd s t a g e . The f i r i n g of e i g h ts o l i d p r o p e l l a n t r o c k e t s f i x e d t o t h e s p i n t a b l e accom-p l i s h e s sp in -u p o f t h e t h i r d s t a g e s p a c e c r a f t a ssem bly .

The ISEE s p a c e c r a f t a r e a t ta c h e d t o t h e t h i r d s t a g e motor .

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I

INTERN ATION AL SUN -EART H EXPLORERS ( ISEE-A Et B)

------TRANS FE R O RBIT

P ARKING O RBITA

DAUG HTE R' S IN IT IAL ORBITAFTER SEPARATION------

I:aI

L B Ln

INITIAL ORBITS


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- 2 7 -

G oddard Space F l i g h t C e n t e r has m anagem ent r e spon-s i b i l i t y f o r ISEE-A and i s d i r e c t l y r e sp o n s i b le f o rt r a c k i n g an d d a t a a c q u i s i t i o n and d a t a p r o ce s s i n g.I S E E - A i s a G o dd a rd -d e si gn e d s 2 a c e c r a f t w i t h alli t s c o mp o ne n ts s u p p l i e d b y U n i t e d S t a t e s i n d u s t r y . I n t e -g r a t i o n a nd t e s t i n g w a s a l s o done a t Goddard.I S E E - B i s an ESA-ESTEC s p a c e c r a f t w i t h D o rn ie rSystems,Frederickshaven, Germany, h e a d i n g t h e c o n t r a c t o rt e a m w hi ch c o n s i s t s o f a c o n so r ti u m o f i n d u s t r i e s i n 1 0E uro pean c o u n t r i e s c a l l e d t h e S T A R Consor t ium.

G o d d a r d d i r e c t s t h e D e l t a r oc ke t p rogram and M cD onne llD o u g l a s A s t r o n a u t i c s CO., H u n t i ng t o n B ea ch , C a l i f . , i sp r i m e c o n t r a c t o r .

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l


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LAUNCH SEQUENCE FOR ISEE-A 6 BE v e n t T i m e A 1 i u d eK i o m e t e'rs/mi l e sL i f t o f f 0 se c .S i x S o l i d M o to r B u r n o u t 38 se c .T h r e e S o l i d M o to rI gn i i o nT h r e e S o l i d M o to rBurnoutN i n e S o l i d M o t o rJ e t t i s o nMain Engine Cutof f(MECO)F i r s t / S e c o n d S t a g eS e p a r a t i o nS ec on d S t a g e I g n i t i o nF a i r i n g J e t t i s o nS ec on d S t a g e C u t o f f It1(SECO # 1 )B e g in C o a s t P h a s eR o l l (1 rpm)End Coas t Phas e Rol lS econd S t a g e I g n i t i o n#2Second S ta ge SecondCut -Off 2 (SECO 2 )T h i r d S t a g e / P a y l o a dSpin-UpJ e t t i s o n S t a ge I1T h i rd S t s g e I g n i t i o nT h i r d S t a g e B u r n ou tPayload S e p a r a t i o n ,A c t i v a t e R e t r o S y s t e m

39 sec,

1 min. 18 sec .

1 min. 2 7 sec .

3 min. 45 sec .

3 min . 54 se c .3 min. 56 s e c .4 min. 56 s e c .

8 min. 4 4 sec .

9 min. 23 s e c .4 4 min. 23 s e c .53 min. 31 s e c .

53 min. 52 se c .

54 min . 50 se c .54 min. 52 sec .55 min. 33 min.56 min. 17 sec .

57 m i n . 3 0 sec .- m o r e -

06

6

2 1

2 6

9 1

9 6991 2 6

157

157275285

04

4

1 3

1 6

56

606 178

97

9 71 7 11 7 7

287 178

32 7 203


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- 3 3 -ISEE-A and B TEAM

NASA H e a d q u a r t e r sD r . N o e l S. H i n n e r s

D r . S . I c h t i a q u e Rasool

T. B l a n d No r r i s

D r . H a r o l d Glaser

Frank GaetanoD r . E r w i n R . S c h m e r l i n gJohn F . Y a r d l e y

J o s e p h B. Mahon

P e t e r T. E a t o nG e r a l d M . T r u s z y n s k i

European Space AqencyRoy GibsonD r . E r n s t T r en d e le n b ur g

D r . Edgar Page

Maurice D e l a h a i s

Derek EatonD r . A l a s t a i r C. Durney

Associate A d m i n i s t r a t o rf o r S p a c e S c i e n c e

Deputy As s o c i a t e A d m i n i s t r a t o rf o r S p ac e S c i e n c e ( S c i e n c e )D i r e c t o r , A s t r o p h y s i c sProgramsDire c to r , S o l a r Te r r e s t r i a lProgramsISEE-A Program ManagerISEE-A Program S c i e n t i s tAssoc ia te A d m i n i s t r a t o r f o rS pa ce F l i g h tD i r e c t o r o f Expendable LaunchV e h i c l e P r o g r a m sManager, D e l t a ProgramA s s o c i a t e A d m i n is t r a t o r f o rT r a c k i n g a n d Data A c q u i s i t i o n

D i r e c t o r G e n e r a lD i r e c t o r of S c i e n t i f i c a n dMeteorological ProgramsHead of S p a c e S c i e n c e D e p a r t m e nEuropean Space TechnologyCenter (ESTEC)Head, S c i e n t i f i c P r o j e c t sESTEC

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ISEE-B Projec t Manager1SFE-R P r o j e c t S c i e n t i s t


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-30-

G od dar d S pa ce F l i g h t C e n t e rD r . R o b e r t S . CooperR o b e r t E . S m y l i eRober t L i n d l e yDon F o r d y c e

J e r e m i a h J . MaddenK e i t h W. O g i l v i eD r . S te p h e n P a d d a c k

James 0 . ReddingJohn A . H r a s t a rM a r t i n A . DavisDavid W . G r i m e sW i l l i a m R . R u s s e l l

R o b e r t G oss

E . Michael Chewning

Thomas C . MooreKenneth McDonaldKennedy Space CenterL e e R . S c h e r e rG e r a l d D . G r i f f i nD r . Walter J . Kapryan

George F . Page

Direc torDeputy Direc to rDi rec to r o f P r o j e c t sA s s o c i a t e D i r e c t o r f o rP r o j e c t sP r o j e c t ManagerP r o j e c t S c i e n t i s tDeputy P r o j e c t Manager,T e c h n i c a1F i n a n c ia1 Manage rM i s s i o n O p e r a t i o n s ManagerS c i e n t i f i c I n s t r u m en t ManagerD e , l t a P r o j e c t M a n a g e rDeputy D e l t a P r o j e c t Manager,T e c h n i c a lC h i e f , Miss ion A n a l y s i s an dI n t e g r a t i o n B ra nc h, D e l t aP r o j e c t O f f i c eD e l t a M is si on I n t e g r a t i o nManagerM is s io n O p e r a t i o n s M an ag erNetwork Su pp or t Manager

D i r e c t o rD e p u ty D i r e c to rD i r e c t o r , S pa ce V e h i c l e sO p e r a t i o n sD i r e c t o r , Expendab leV e h i c l e s

- m o r e -


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-31-

K ennedy ( con t ' d )W. C . T hacke r

Wayne M c C a l l

Edmund M . C h a f f i nC o n t r a c t o r sD o r n i e r S v s t e m sF r i e d r i c h s h a f e n , G e r m a n yMcDonnell DouglasA s t r o n a u t i c s C o .H unt i ng t on , B each , C a l i f .

C h i e f , D e l t a O p e r a t i o n sD i v i s i o nC h i e f Eng ineer , DeltaO p e r a t i o n sS p a c e c r a f t C o o r d in a t or

ISEE-B S p a c e c r a f t ( p r i m e

D e l t a Launch Vehic le

ISEE-B w a s d e s i g n e d a n d c o n s t r u c t e d by t h e E ur op ea nSTAR C onso r t i um of c o mp an ie s u n d er c o n t r a c t t o t h eEuropean Space Agency. Dornier Systems a s pr i m e c o n t r a c t o ri s r e s p o n s i b l e f o r p r o j e c t m ana gem en t, s y s t e m s e n g i n e e r i n g ,a t t i t u d e and o r b i t c o n t r o l , w i r e h a r n e s s , a s s e m b l y i n t e g r a t i o nand t e s t a n d l a u n c h s u p p o r t .

O th er STAR con so rt iu m t e a m m e m b e r s a r e :S t r u c t u r e C o n tr a ve s , S w i t z e r l an dT e l ecom m uni ca t i ons andd a t a h a n d li n g

Thomson-CSF, FrancePlontedel Laben SPA , I t a l yA E G , GermanyL.N. F r i c s s o n , S w e d e n

A t t i t u d e a nd O r b i t C o nt ro l B r i t i s h A i r c r a f t C o r p . ,United KingdomSEP, F r a n c eF o k k e r , N e t h e r l a n d sS o l a r A r ra yP o w e r S u p p l i e s

A E G , GermanyFIAR, I t a l yE l e c t r o n i k c e n t r a l e n , D e n m a r kF o k k e r , N e t h e r l a n d sD o r n i e r Systems, Germany

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