16
Adv. Space Res. Vol. 7, No. 12, pp. (12)185—(12)200, 1987 0273—1177/87$0.00 + .50 Printed in Great Britain. All rights reserved. Copyright © 1987 COSPAR THE PHOBOS MISSION: SCIENTIFIC GOALS R. Z. Sagdeev, V. M. Balebanov, A. V. Zakharov, J. M. Kovtunenko, R. S. Kremnev, L. V. Ksanfomality and G. N. Rogovsky Space Research Institute of the Academy of Sciences of the U.S.S.R. The Phobos mission represents a new type of scientific program having multiple scientific goals including investigation of Phobos, Mars, the Sun and interplanetary medium. The Phobos investigations will be made from very close distances - approximately 5Cm from the surface. Important scientific goals are to obtain TV images of the surface, active and passive studies of its chemical and mineralogical composition, its physical properties and other experiments. Experiments are planned which will probe, by means of radiophy- sical methods, the properties of the Phobos surface down to depths of 20Cm. Also planned are sounders onboard the spacecraft having a number of scienti- fic experiment which will measi~ire ~he physiçal.paramete~s Qf Phol?os. ~The go- als of the planned Mars investigation include ionospheric investigations, studies of the atmospheric aerosol component and dynamical atmospheric pheno- mena. A number of experiments will study the physics of the Sun, including its corona and upper chromosphere, solar oscillation, solar flares activity and solar constant determination. The investigation of the interplanetary me- dium includes studies of the solar wind, interplanetary shock waves, solar cosmic ray propagation and cosmic gamma bursts. The Phobos project represents an extensive collaboration between inter- national scientific groups. The launch of two Soviet Phobos spacecrafts is planned in the mid of 1988. They are the vehicles of new generation which are intended for study- ing Martian satellites, Mars itself, the processes occurring on the Sun and in the interplanetary space medium, within the framework of the multiobjec- tive program. The PI-IOBOS spacecraft (Figure 1) will carry scientific payload for 22 experiments and two descenders, each with its own scientific instruments.The study of the Martian satellite Phobos is of high priority (Figure 2). Though being only minor part of the mission they require much time for forming a precise orbit. To study Phobos thoroughly, the mission program envisages the approach of the spacecraft to its surface as close as about 5Cm and the drift flight over it with a velocity of 2 to 5m/s (Figure 3). During the drift two descenders will be jettisoned which then land on Phobos’ surface and begin their experiments. After this, the spacecraft will be transferred to a circular orbit and operate following the Mars study program; in this phase the spacecraft will periodically approach Phobos at a distance of 50km. The PHOBOS mission pro- gram may be widened if the proposal about the use of the second spacecraft for studying Demos is accepted. The study of such celestial bodies of the Solar system as Martian satel- lites Phobos and Demos is of particular scientific interest. Both satellites are the small bodies of the Solar system, may be of preplanetary origin, and are irregular in shape. According to one hypothesis they can be referred to asteroids of the C class captured by Mars. However, many scientists have an alternative opinion. Both satellites have a very dark rough surface with a geometric albedo of about 5%, superimposed by impact craters. Characteristic sizes of Phobos and Deimos (major axis) are 27 and 15km, respectively. Rego- lith, the surface soil layer, has been reworked owing to meteorite impacts and the solar wind. Hence, the study of regolith would yield the data not on- ly about the conditions of formation of the bodies in the Solar system but also about their further evolution. (12)185

The phobos mission: Scientific goals

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Adv. SpaceRes.Vol. 7, No. 12, pp. (12)185—(12)200,1987 0273—1177/87$0.00 + .50Printedin GreatBritain. All rights reserved. Copyright© 1987COSPAR

THE PHOBOS MISSION: SCIENTIFIC GOALS

R. Z. Sagdeev,V. M. Balebanov,A. V. Zakharov,J. M. Kovtunenko,R. S. Kremnev,L. V. KsanfomalityandG. N. Rogovsky

SpaceResearchInstitute of theAcademyof Sciencesof theU.S.S.R.

The Phobos mission represents a new type of scientific program havingmultiple scientific goals including investigation of Phobos, Mars, the Sunand interplanetary medium. The Phobos investigations will be made from veryclose distances - approximately 5Cm from the surface. Important scientificgoals are to obtain TV images of the surface, active and passive studies ofits chemical and mineralogical composition, its physical properties and otherexperiments. Experiments are planned which will probe, by means of radiophy-sical methods, the properties of the Phobos surface down to depths of 20Cm.Also planned are sounders onboard the spacecraft having a number of scienti-fic experiment which will measi~ire ~he physiçal.paramete~s Qf Phol?os. ~The go-als of the planned Mars investigation include ionospheric investigations,studies of the atmospheric aerosol component and dynamical atmospheric pheno-mena. A number of experiments will study the physics of the Sun, includingits corona and upper chromosphere, solar oscillation, solar flares activityand solar constant determination. The investigation of the interplanetary me-dium includes studies of the solar wind, interplanetary shock waves, solarcosmic ray propagation and cosmic gamma bursts.

The Phobos project represents an extensive collaboration between inter-national scientific groups.

The launch of two Soviet Phobos spacecrafts is planned in the mid of1988. They are the vehicles of new generation which are intended for study-ing Martian satellites, Mars itself, the processes occurring on the Sun andin the interplanetary space medium, within the framework of the multiobjec-tive program.

The PI-IOBOS spacecraft (Figure 1) will carry scientific payload for 22experiments and two descenders, each with its own scientific instruments.Thestudy of the Martian satellite Phobos is of high priority (Figure 2). Thoughbeing only minor part of the mission they require much time for forming aprecise orbit. To study Phobos thoroughly, the mission program envisages theapproach of the spacecraft to its surface as close as about 5Cm and the driftflight over it with a velocity of 2 to 5m/s (Figure 3). During the drift twodescenders will be jettisoned which then land on Phobos’ surface and begintheir experiments.

After this, the spacecraft will be transferred to a circular orbit andoperate following the Mars study program; in this phase the spacecraft willperiodically approach Phobos at a distance of 50km. The PHOBOSmission pro-gram may be widened if the proposal about the use of the second spacecraftfor studying Demos is accepted.

The study of such celestial bodies of the Solar system as Martian satel-lites Phobos and Demos is of particular scientific interest. Both satellitesare the small bodies of the Solar system, may be of preplanetary origin, andare irregular in shape. According to one hypothesis they can be referred toasteroids of the C class captured by Mars. However, many scientists have analternative opinion. Both satellites have a very dark rough surface with ageometric albedo of about 5%, superimposed by impact craters. Characteristicsizes of Phobos and Deimos (major axis) are 27 and 15km, respectively. Rego-lith, the surface soil layer, has been reworked owing to meteorite impactsand the solar wind. Hence, the study of regolith would yield the data not on-ly about the conditions of formation of the bodies in the Solar system butalso about their further evolution.

(12)185

(12)186 R. Z. Sagdeevet al.

The VIKING data allowed detection of the sort of unknown features on Pho-bos, many linear and subparallel furrows 200-30Cm wide and 20-3Cm deep (Fi-gure 4). Almost all of them converge to the biggest crater Stickney 10kmacross, more than a third of the diameter of the satellite itself. An impactwith a large meteorite apparently caused not only the formation of an enormo-us crater but also the craking of Phobos. However, this hypothesis does notexplain subparallel furrows and also some other features.

The mass of Phobos is close to 1019 g (approximately l.5.1C8 of the Mar-tian mass) which corresponds to a mean density of about 2g.cm-3. Therefore,Phobos cannot consist of dense volcanic rocks of which the crust and uppermantle of terrestrial planets are composed.

Spectroscopy of the Phobos reflectivity shows that it is similar to thatof carbonaceous chondrites whose composition is characterized by a low densi-ty, 1.5 to 2.5g.cm

3.

The reflection properties of Demos’ surface suggest the same materialas Phobos consists of. However, the relief of Deimos is different, its sur-face is not furrowed (with no large craters), many small craters and stonyboulders are fully or partially covered by regolith, maybe, of several tensof meters in depth. As distinguished from Phobos the craters on Deiinos havea characteristic light borders. Both satellites are in synchronous revolution(they always See Mars with the same side).

Figure 5 presents the scientific objectives of the Phobos study. However,now we shall discuss briefly the other objectives of the PHOBOSProject.

The Mars surface is planned to be studied by remote sensing methods inthe visible infrared ultraviolet, and gamma spectral regions. The programenvisages also the studies 0± the planet s plasma shell and magnetosphere.Before approach to Phobos the spacecraft will successively change several in-termediate orbit, one of them is elliptic, with a pericenter of several hun-dred kilometers (Figure 6). At this period of the closest approach to Marsand after the spacecraft goes away from Phobos the most intensive measure-ments of Mars’ surface are planned (Figure 7).

The PHOBOSProject includes also the studies of the Sun. The electromag-netic radiation of the Sun will be investigated in the wide frequency rangefrom the soft ultraviolet to hard gamma. One of the objective of the experi-ment is to image the Sun in the X-ray, to study the evolution of large-scalestructures, to determine physical conditions in the flares and in the activeregions, corona holes and bright points, to identify the mechanism of magne-tic energy transformation into corona plasma heating, to study turbulent anddirectional plasma motions and electron acceleration. After the launch thespacecraft is moving away grom the Earth and the angle the spacecraft - Sun -

- Earth will change from 0 to about 1800. So the Sun will be observed con-currently from the spacecraft, Earth, and the near-earth satellites that al-low restoring the three-dimensional structure of the Solar corona and chromo-sphere. The spacecraft in Mars’ orbit will permit to study processes on theSun unobservable from the Earth. This method is of interest for reliable pre-diction of Solar activity manifestations. Figure 8 lists solar experiments.

The studies of the plasma and plasma formations in the interplanetaryspace and the registration of cosmic gamma-bursts are planned for the Earth--to-Mars flight stage (Figure 9).

~periments on board the PHOBOSspacecraft

Images and spectral characteristics of Phobos’ surface will be obtainedwith a TV-system (Figure 10). A morphological analysis on Phobos will be bas-ed on TV images.

The TV-system will provide imaging in three spectral channels to obtaincomposite images. The features of more than 6cm in size one can identify dur-ing the approach to Phobos. Concurrently spectrometry of images sites is con-ducted in 14 bands at a re$olution of SOnin.

Changes in the direction of the line of sight, using a rotational mirror,make possible mapping and wide-coverage horizontal surveys of Phobos. Alsoimages of Mars and brightest stars can be obtained (the latter is importantfor navigation).

The images and spectrograms thus obtained, permit mapping of Phobos (to-pographic, spectral radiance, texture/morphology maps, etc) and position re-

The PhobosMission (12)187

ferencing of the measurements made by other scientific instruments.

During approaching Phobos the program envisages two active experimentsfor studying the chemical and isokopic composition of the surface. One ofthem is of the soil substances evaporated and iRnized by a laser beam (theenergy density in the beam is of an order of l0~W) focussed following thelaser ranger (Figure 11). Then some freely scattering ions return to thespacecraft and are subject to mass~-spectrometric analysis in a reflectronwith a retarding field. The analysis is based on measurements of the ion time--of-flight from the study area to the spacecraft.

The objective of the other active experiment is to study the Phobos’ sur-face soil composition (a layer of _lC~) and to determine element implanted bythe solar wind. The methodology includes the injection of an ion beam fromthe spacecraft and measurements of mass spectra of secondary ions knocked outfrom the surface layer. Mass spectra of secondary ions will be recorded witha quadrupole mass spectrometer (Figure 12). Both experiments will be carriedout only near Phobos’ surface.

The structure of the underlying ground layer, topography and electrophy-sical characteristics of Phobos’ soil will be studied with a method of radiosounding from the spacecraft (Figure 13). The sounding frequency range isfrom 5 to 500 MHz the sounding depth is up to 200m. The radio system is plan-ned also for studying the Martian ionosphere.

The experiment intended to study the thermal physics (5-5011m) and reflec-tion properties (O.3-O.9pm) should yield also the data about the mineral com-position of the Phobos and Mars surface analyzing near IR spectra (l-3pm).A characteristic feature of the experiment is the simultaneous use of sevçralinstruments: a combined radiometer, a photometer and an IR spectrometer withan angular resolution of 12’ (spectrometer - 128 subregions), 16’ (photometer10 subregions), 30’ (radiometer - 6 subregions). The spectrometer can alsooperate in a scanning mode (Figure 14). The thermal physics of the Phobos andMars soil in the narrower range, 8-l2.5~m, hut in a scanning mode with a highangular resolution of 1’ is planned to study with a high-sensitive scanningradiometer.

The objectives of this experiment are to obtain thermal/physical proper-ties of Phobos’ surface and brightness temperature maps of Mars’ surface, tostudy the durinal and seasonal dynamics of the temperature regime of Mars’surface, to measure thermal inertia of Martiaii soils, to search for sites ofendogenous heat release and regions with higher humidity and permafrost. Thedata acquired will also give an idea about the mineralogical distributionover the Martian surface.

Besides the above remote methods the Project envisages direct (contact)measurements by means of two probes which will be landed on Phobos’ surfaceand remain be active for some time.

During the drift over Phobos’ surface at a height of about 50m the prob-es will be jettisoned from the spacecraft. They reach the surface with a ve-locity of about lm/s. The first probe is an immobile long-term automated sta-tion. After the touchdown the station will be fixed on the surface and beginits long-term measurements:

- experiments on celestia~l mechanics made with the station radio system andground-based receiving/transmitting stations;- study of Phobos libration performed by measuring autonomously the Sun’sangular position with an optical sensor and using radiointerferometry withthe help of signals from two sensors spaced on the surface (each of the twospacecrafts is to deliver its own station on Phobos’ surface);- measurements of seismic noise due to the Martian gravitational field andthermal stresses, and also due to impact of meteorites.

The other group of experiments is intended for studying the elementalcomposition of the surface layer, its structure and physical/mechanical pro-perties. To this end it is equipped with an n-scattering and X-ray fluores-cence spectrometer, a penetrometer with temperature sensors and an accelero-meter, and a TV-camera (Figure 15).

Station radio signals will be transmitted directly to the Earth at thefrequency 1672 MHz and received by USSR ground-based stations. Besides, ra-diotelescopes distributed over West Europe and Western Hemisphere are sup-posed to receive this telemetry data (when the station will be beyond the vi-sibility range from the USSR territory) and to measure it’s angular positionrelative to quasars using the VLBI technique. The data transmission rate is

(12)188 R. Z. Sagdeevet al.

4 to 20 bit/s depending on the range and the transmitting antenna orientation.The data are planned to be dumpted to the Earth on each second orbit aroundMars at the day time, each communication session will continue 30 minutes.Range measurements should provide basic information for experiments on cele-stial mechanics. The expected accuracy of these measurements is about Sm.

Radio signals from the orbiting spacecraft at Scm required to accountfor the ambient effects on the range measurements will be received by theUSSR ground-based stations. The station will be operating on Phobos for abouta year.

The second landing probe (hopper) will be able to move on Phobos’ surface(Figure 16). After landing and settling down on the surface it is driven intoits operating position by a set of rods of the position-control device. Thenscientific measurements are conducted. Information is relayed via the radiolink of the spacecraft to the Earth. The next measurement cycle starts afterthe hopper hops, with the help of a pusher, over up to 2Oin. After damping thehopper is ready to repeat an operation cycle. The number of cycles may be upto 10 and depends on the communication session duration. The hopper proceedswith its activity during the next communication sessions with the spacecraft.

The scientific equipment of the hopper incorporates an accelerometer tomeasure accelerations resulting from impacts with the surface: an X-ray spe-ctrofluorimeter to study chemical composition of the surface soil; a penetro-meter to study its physical and mechanical properties; a magnetometer to mea-sure magnetic fields; a gravimeter to measure Phobos mass and local gravita-tional anomalies.

Thus the probes will yield for the first time directly mea~ured data onthe soil layer Isurface and near-surface) structure, on the chemical and mi-neral composition of Phobos’ surface.

The gamma-radiation of the surface due to the effect of galactic cosmicrays and natural radioactivity causes the characteristic emission from rock-forming elements within 0.1 to 10 MeV. A crystal C5J (Tt) with a volume of785cm

3 is used as a detector. The objective of the new experiment is to de-termine the content of basic rock-forming elements 0, Mg, Al, Si, Ca, Fe andnatural radioactive elements U, Th and K. This experiment allows the informa-tion about the character of rocks, their chemical composition and, therefore,about the degree of rock differentiation in the process of their formation.The experiment is designed for studying both Mars and Phobos.

The other experiment will measure the flux of neutrons within the rangefrom 0.025 eV to 2MeV and yield the data about the content of bound water andcertain elements in the surface layer of Phobos’ soil.

The Project envisages the experiment to study the Martian atmosphere.It is planned to measure the vertical concentration distribution of ozone,water vapor, molecular oxygen, dust; to determine vertical profiles of tempe-rature and pressure, seasonal, local and durinal variation of atmosphericparameters; and to record deuterium/hydrogen ratios. The methodology of mea-surements employs measuring spectra of solar radiation which passed Mars’atmosphere during the spacecraft ingress into or ingress from the shadow ofthe planet (Figure 17).

The PHOBOSspacecraft has the instrumentation for studying plasma proper-ties during its orbiting around the planet and for collecting the data aboutthe peculiarities of the solar wind interaction with Mars and about its mag-netosphere characteristics.

The measurements of the ion mass composition are planned in the Martianionosphere as well as the determination of moments of the distribution func-tion of ions and electrons in the planet’s vicinity and the studies of struc-tural formation and dynamics of the Martian magnetosphere. It will be the ex-periment (Figure 18) to obtain a three-dimensional distribution function forelectrons and major types of positive ions in Mars’ vicinity.

One of the basic diagnostic methods used for investigating the plasmais the study of the plasma waves. In the collisionless plasma wave processesdetermine the character of the plasma particle interaction. It is the studi-es of plasma oscillations together with the measurements of the magnetic fieldand plasma characteristics that allow identifying reliably the processes inthe solar wind flow around a planet and in planetary magnetosphere. The plan-ned wave experiment (Figure 19) will use a combined technique: diagnosticstogether with measurements of the electric and magnetic fields and variationsof the plasma flow as well.

ThePhobosMission (12)189

Magnetometric measurements will be carried out with two almost identic-al flux-gate magnetometers with a resolution of 0.O5nT.

The PHOBOSsolar instrumentation segment includes a telescope/corona-graph with three optical channels in a detector unit (Figure 20). Each chan-nel features focusing optics, band filters, and cooled CCD-array to get imag-es.

Monitoring the solar activity processes and forming solar-flare X-raysignal to point the spacecraft to the Sun with a high accuracy and to switchon the solar-segment instruments will be conducted with a special-purpose mo-nitor. The analysis of the collected data will help investigate solar flareprecursors.

Nuclear gamma-radiation lines are also the subject of interest in thesolar flare studies. The important objective of this experiment is to studyin detail the energy spectra of gamma-bursts in the 3-l000KeV range with a128-channel amplitude analyzer. The high time resolution of the instrumentpermits investigation of the periodicity and the fine time structure of solarand cosmic gamma-bursts.

One more interesting solar experiment is aimed at examining Sun’s innerstructure and dynamics by registering solar oscillations. The experiment isdesigned so that the solar radiation intensity is measured continuously fora long time with a high accuracy in three narrow spectral bands. The instru-ment features three solar photometers with interference filters and a solaraspect sensors. Silicon diodes are employed as detectors.

Observations of the solar electromagnetic radiation will be to a great-er extent supplemented with the data about corpuscular fluxes (the solar wind)and solar cosmic rays generated during solar ±lares. To study the three-di-mensional velocity distribution function of the solar-wind principal compo-nents and the solar cosmic rays several spectrometers will be employed whichallow measuring the energy, mass, and charge composition of the corpuscularradiation and basic parameters of the plasma distribution function (Figure 21).These instruments will also be used for studying plasma parameters near Mars.

Agencies, scientists, and specialists from Austria, Bulgaria, Czechoslo-vakia, European Space Agency (ESA), Finland, France, the German Democratic Re-public, Hungary, the Max-Planck Institut (FRG), Poland, the Soviet Union,Switzerland, and Sweden are being involved in developing scientific programsof the PHOBOSProject, in designing and manufacturing scientific instrumenta-tion, and in conducting the experiments.

CAPTIONS

Figure 1 PHOBOSspacecraft: General view.Figure 2 Spacecraft Approach to Phobos.Figure 3 Scheme of spacecraft approach to Phobos.Figure 4 Viking photos of the surface of Phobos and Deimos.Figure 5 Scientific objectives of Phobos studies.Figure 6 Spacecraft trajectories.Figure 7 Scientific objectives of Mars studies.Figure 8 Scientific objectives of Solar studies.Figure 9 Scientific objectives of studies of the interplanetary

space.Figure 10 Surveying and mapping of the Mars and Phobos surface.Figure 11 Remote laser mass-spectrometric analysis of the soil

composition.Figure 12 Remote mass-analysis of secondary ions.Figure 13 Radar studies of Phobos.Figure 14 Radiometric (thermal) and spectral measurements.Figure 15 Long-term automated station.Figure 16 Moving lander (hopper).Figure 17 Spectrometry of the chemical composition of the Martian

atmosphere.Figure 18 Studies of the space plasma with a scanning analyzer.Figure 19 Studies of plasma waves.Figure 20 Studies of the solar electromagnetic radiation.Figure 21 Studies of the solar wind and solar cosmic rays.

(12)190 R. Z. Sagdeev etal.

~ ~

~-~r ‘~,

Figure 1 PHOBDS spacecraft: General view.

to th\Sun to theAEarch

Synchranous orbit (Orbit ~.)

.4 /•_•_

30 k

-~--

~ SOn

Phobos Phohog orbit

Figure3 VRelative velocity during the opacecroft

Schen~of spacecraft a~~roac~hth Phobos. hovering over Phobo,’ surfoce — 2 to eR.Time of the opacecraft hovering at 50 mover Phobos’ surface — 15 to 20 ni,~

PHOE~S

SURF ACECHEMICAL COMPOSITIONMINERAL COMPOSITION

SURFACE IMAGERY WIT-~~-]I~HSPATIAL RESOLUTION

TrIERMAL MAPPHYSICAL PRI°ERTIES

RAUIO’~ETP.IC CHARACTERISTICS

INNER STPUCT~RE

LAR~ESCALESTF,UC.iUR~

SE 1 SM~L~GVRADIOMITEIC CHARACTERISTiCS

ORBITAL MOTION

CHIC ~ r~T~EnLIF~‘TICS

SECULAR DEcELEP.M:CN

Figure 5 Scientific objectives of PhCObOS studies.

The PhobosMission (12)191

CbI1HH(EHIIE C cI,OBOCOM

r4 4

/ ....Ld( ~

Figure 2 Spacecraft1i~pproachto Phohos.

(12)192 R. Z. Sagdeeveta!.

1400km 1400kmPHOBOS DEIMOS120km 50km

,Tk.#0 IVA~A

HFigure 4 Viking photos of the surface ofPhobosand Demos.

The Phobos Mission (12)193

Orbit 1

Orbit 2 Deirnos orbit‘N. n~•*i

U1I1.LV )

Approaching to Mars Phobo5 orbit

11Mars

Interplanetary

Marsorbit path

SunTo

Tranuition to the

cynchronous orbit

Start

Inserting into the Mars’

satellite orbit Figure 6 spacecraft trajectories.

MARS

SURFACE

CHEMICAL COMPOSITIONMINERAL COMPOSITIONIMAGERY OF THE PLANETTHERMALMAPRADIOMETRIC CHARACTERISTICS

ATMOSPHE RE

CHEMICAL COMPOSITIONDENSITY PROFILETEMPERATUREPROFILEDUST DENSITYDYNAMICS~EVOLUTION

IONOSPHERE

DENSITY PROFILEDYNAMICS

MA ONE TOS PH E RE

PARAMETERSOF THE MARTIAN MAGNETIC DIPOLE, ITS MOMENTAND ORIENTATIOnpLASMA ION AND ENERGY COMPOSITIONTHREE—DIMENSIONAL FUNCTION OF PLASMA DISTRIbUTIONCHARACTERISTICS OP PLASMA- WAVES (ELECTRIC AND MAGEETIC FIELDS)STRUCTUREOF MAGNETOSPHERE AND ITS BOUNDARIES

Figure 7 Scientific objectives of Mars studies.

(12)194 R. Z. Sagdeeveta!.

S UNCORONA AND UPPER CHROMOSPHERE

LARGE-SCALE STRUCTUREACTIVE REGIONSBRIGHT SPOTSCORONALHOLES

SOLAR FLARESPRECURSORSAND TRANSIENT SOURCESEXPLOSION STAGELOCALIZATION OF THE ACCELERATION REGION

SOLAR OSCILLATIONS

HELIOSEISMOLOGYSPECTRUMOF PRESSUREAND GRAVITY MODES

SOLAR ACTIVITY FORECASTING

DIRECT OBSERVATIONSOF SOLAR ACTIVITY CENTERS AT THE SOLARSIDE INVISIBLE FROMEARTHUPDATING OF THE SPECTRUMDISTRIBUTION OF THE SOLAR CONSTANT

Figure 8 Scientific objectives of Solar studies.

INTERPLANETARY MEDIUM

SOLAR WINDENERGY. ION AND CHARGECOMPOSITION

VELOCITY DISTRIBUTION FUNCTION

SOLAR COSMIC RAYS

SPECTRAANISOTROPYACCELERATI ON MECHANISMS

INTERPLANETARY SHOCKS

DIAGNOSTICS OF SHOCKSSTRUCTUREOF INTERPLANETARYSHOCKS

A SHOCKNEAR MARSCOSMIC AND SOLAR GAMMA—BURSTS

LOCALI ZATION

SPECTRA

Figure 9 Scientific objectives of studies of the interplanetary

space.

EXPERIMENT FREGAT (BULGARiA, GDR, USSR)0 B .1 E C T I V E S

— IMAGES AND SPECTROGRAMSOF PHOBOS’ SURFACE— POSITION ~FERENCINGEOR MEAEUREM~NTS MADE BY .OTHER.1NS1’I~UMENTS— THEMATIC MAPS OF PHOBOS (TOPOGRAPHIC. SPECTRAL RADIANCE. TEXTURE!

MORPHOLOGY MAPS, ETC.)

FREGAT FEATURES:THREE CAMERAS, A SPECTROMETERAND AN ON—BOARDMEMORYUNIT

THE TV CAMERASMAKE A SIMULTANEOUS SURVEYINGIN THREE SPECTRAL CHANNELS

AND THUS ALLOW FOR COMPOSITE IMAGES WITH THE FOLLOWINGCHARACTERISTICS:Distance to object 6300 800 50 0 05

to be survcyed,km

Surface resolution 7000 900 60 0.06

/without blurrxng/,ni

One-frame coverage,km 3000x3000 400x300 2Sx19 25.1O3x19.)03

THE SPECTROMETERIS SCANNING THE SURFACE UNDER STUDY BY-A SLOT PARALLEL t,ND ABOUTEQUAL TO A TV FRAME SiDE. THE DISPERSIVE SPECTROMETERSYSTEM ENSURES SPECTROWTNYIN 1.1 SPECTRAL BANDS FROM 0.4 to 1.1 p AT A RESOLUTION OF 50 nm

CHANGES IN THE DIF1ECTION OF THE LINE OF SIGHT, QS1~A ROTATIONAL MIRROR. MAREPOSSIBLE VERTICAL. AND WIDE-COVERAGESURVEYS OF FHUbUS, NOT ONLY CAN IMAGES OFMARS AND PHOBOS BE OBTAINED BUT ALSO THOSE OF BRIGHTEST STARS WHICH ARE 1t.t00RT~NTFOR NAVIGATION.THE ON—BOARD MEMORY UNIT PERMITS RECORDING 1100 FULL FRAMES (3 TV FRAMES ANDSPECTROGRAM) AT A RATE OF 2Mbit.s1 AND THEIR READING AND DUMPING — Vi4CHANNEL TO EARTH AT A RATE OF 4y.bjt.s1.

TIlE TOTAL MASS IS 50 kg.

Figure 10 Surveying and mapping of the Mars and Phobos surface.

aaaaaaaaaaaaa

The Phobos Mission (12)195

LIH1L-D EXPERIMENT (AUSTRIA, BULGARIA. CSSR, GDR, MPK~PRO, USSR)

OBJECT I VE~

DETFSWIHATIOM OF THE ELEMENTALAND ISOTOPICSOIL COMPOSITION OF THE PI40B05 SURFACE

THE SOIL LAYER ANALYED IS 1-2u:n DEEP OH TIlE AREA

~ IN DIAMETER

METHODOLOGYIS BASED ON’ MEASUREMENTSOF THE SOIL SUB- ElectrontcsSTANCES EVAI’oRxFF.t’ AND I0.MI lED BY A LASER SEAN FO-205531 WITH ThE HELP OF ‘IHE LASER ALTIMETER DATA.THEN FOLLOWS A MASS-SPECTROMETRIC ANALYSIS OF FREELYSCATTE~rNCIONS IN A REFLECTRON WITH A RE’IARDINC .

FIELD. THE ION TIME-OF-FLIGIIT FROM THE STUDY AREA TO -

TIlE SPACECRAFT tS RECORDED~ DURING ONE CYCLE OF MEA-SUREMENTS APPROXIMATELY i~6 IONS WILL BE COUNTED ATA DISTANCE OP SOrn. THE DATA ARE TO 513 PROCESSEDABOARD / //THE SPACECRAFT I /3’. ,‘,

/ // ,,Mass t503e 1-200 a.u.a. 1,1 /Macs resol,atleo M/~5i4 150 ~..)

Laser beam ,Jasloiength 1,O6Bm 5.. -

Pulse aflOrgy O•5.T LaserPulse duration 1.0 no unit ~. 4Laser pulse rate 0.1 tO 0.2 Re with R El Ct Ont’acu~sed boom diameter 1—2 em s 2 ran ~— C C rEne.’~y density in spot (1 to 2) 10 U/em - finderMeasurement cycle S—toInstrumaut mass 70 kI

• •..‘~:~

I/~x—P1z:rick Ensti tirE fUr Ne rnphya1k (Heidelberg) EXPERIMEST SCHEMATIC

Figure 11 Renote laser mass-spectratetricanalysis of the soil

conposition.

F! ON £ EPE [ElMiNT (AUSTRIA • FRANCE• USSR)

OS 1 1 C I I V E:Elo~tronic~

STUDY Ct THE PHQBOS’ SURFACESOIL COMPOSITION(A LAYER CF lOA) AND CETERMLNATIONOF ELEMENTSIMPLANTED EY THE SOLAR WIND

PETN000LOG’( INCLUDEI - TWO PROCEDURES: ThE INJECTION OF ANION BEAM FROM THE SPACECRAFT BEING AT A DISTANCE OF SO-lOOmFROM SHE SURFACES AND THE MEASUREMENTOF A MASS COMPOSITION -

OF SECONDARY ICNS KNOCKED OUT OF THE SURFACE SOIL LAYER UNDERSTUDY

MASS SPECTRA-OF SECONDARYIONS WILL BE MEASURED WITH A QUADRU—POLE MASS-ANALYZERTHE EXPERIMENT ENVISAGES ALSO-SPECTROMETRYOF SECONDARYIONSKNOCKED—OUTFROM THE SURFACE BY THE SOLAR WINO

Ion mass range 1 to 60 a.u.m.Mass resolution 100 to 150 IonMaximum counting rate io~~ injector Mass-Injection pulse duration is SpecEroPulse repetition rate 0.2Hz meterBe~~Current —2 mAIon hess energy 2-3 koV . -

Working medium krypton . ~ -

Was5 18 kg .~~j.7;’~’ ~ ‘~ ~

~. ~

~j f4.i~ (~I ç

:;Phobos

Figure 12 Re!I*~temass—analysisof secondaryions. EXPERIMENT SCHEMATIC

(12)196 R. Z. Sagdeev et a!.

GRUNT EXPERIMENT (USSR)

SCHEMATIC OF THE EXPERIMENT

0 B J E C T I V E: Spacecraft

STUDY OF THE RELIEFTHE SUBSURFACESTRUCTUREAND ELECTROPHYSICALCHARACTERISTICS OF THE PH030S SOIL

THE METHODOF RADIO SOUNDING IS EMPLOYEDFROMTHE SPACECRAFTDRIFTING AT A SMALL HEICHT OVERTHE PHOBOSSURFACE

\SOUNDINGFREQUENCY, MHz 5.0 330 500SOUNDING DEPTH. m ~2OO 100 30to to200 100RESOLUTION, in 150 3.0 0.35

TO IMPLEMENT THE EXPERIMENT A SPECIAL RADARPACKAGE lS USED —~~‘ ‘SI’

~_[

INSTRUMENT MASS 35 kg

/-~ ~

Figure 13 Radarsthdies of Ph~os. ~bOs

INPENTIIEN’IS XRFM 1511 (ussR, FRANCE). AND TERMOSKAN’ (USSR)

3 8 .2 i C F I V 1 5:S pcc t ro punt ace ter(0 3—0 9 ~n)— THE THERMAL PHYSICS AND-REFLECTION PROPERTIES

IF THE SURFACE OF MARS ~D P110805— MISIRAL COIIPOSIEIOR OF THE SURFACE OF WARS AND SoP908CC

— A TEM’ERATURI MAP OF THE MARS AND PHOBOSSURFACE

~n.s-~---

, -a-.— DIIJP.NAL AND SEASONAL-DYBAMICSOF THE THERMAL RadiometerEAL.ASCE OF MARS SURFACE ‘ SOIL ($-67~m)— THE OIERMAL INERTIA OF PARS 4— SEARCH FOR SIT’ES OP EN000ENOUSNEAT RELEASE AchTASS PERMAFROSTREGIONS ON THE MARS SURFACE ModelRADICMETER- SPECTRO- SCANNINGSPECTROPIIOTO- METER RADIOMETER

l’IEIER KRFFI 15W TEmIOSKAN

4SPECTRALRANGE 567 030.9 0,8-3.5 8-23 andScanning(ire) 0.4—1.1 -nirror

RESOLUTION (51) bands

IFOV loin, of 30 16 12crc)

lION (to):SURFACERESOLIJ- - • ‘Diffraction

PIIOBOSSPECTRAL 6 spectral 50 cm 20 cm - 3~ors’~(6300 km — height) 35 26 22 2 0(350 krs — height) 3 1.5 1.2 0.11SCAN A.NGLE, degree 50 7.34Swan! 510111 MEASURED Seissorait NADIR iron

INSTRU~inNTMASS~g 11.6 (XRFM-ISH) 20 Spectrometer grating6100 km height km 830SCAN AATh,llsc.s1 1.

(O.B—3.5 so)

OPTICAl. SET tPFM-I

Figure 14 Radici~tric (thermal) and spectral measuregnents.

AAAAaa

ininininininaaaa

The Phobos Mission (12)197

to thU Sin

Instriin~nt Objective 4ce-backecattering pocition of ‘\ ~and X—ray fluo- PNOLOS’ stir- USSRrescence face

Optical sensor Phobos libi-a- ra000, _________________

of Sun’s angular USSR Solar panels

Seism~mctor Phobos’ inner USS[E

RAZREZ Penetro— Physical/mocha—meter with tern- nical preperti-peracuro sensors es of the uppar USSRand acceloromat— surface layer ITV—camora Wicroatructure France,

of the surface USSR

Radio sys tern shobo~ Franc’ -

~~0i~Rcro Coistil of LA!, Mungsry ~ P 0~~,.Penetratin~ orobe

Figure 15 Long-termautanatedstation. SCHZMATIC OE LAL

~neraIVi~w ___ jettisoning from the

settling down separation

—~

/ Scientific payload (USSR):

/ — x-ray fluorescence spectrometer/ - magnetometer

- ponetrometer hop

_________________ / -

- I - gratitmeter

position Scientific

__ ~js ts~~

I exiesdsbl cupoort

Figure 16 l&cving lander (hopper).

(12) 198 R. Z. Sagdeev et al

EXPERIMENT AU~IJST (FRANCE, USSR)

O B U E C T I V E: Ssectroineter

AtmosphereMEACUGEMENTS OF VERTICAL DISTRIBUTIO~1SOF OZONE, WATER VAPOR, MOLECULAROXY

orbitC-EN, AND DUST NUMBER—DENSITIES; OF VER— pacecraftTlCAL-PR0FILES~ TEMPERA1’URE -AND PRES-SURE ALONG -MI TM SEASONAL, LOCAL, ANDDI U~NAL VAR! ATIONS OF ATXIOSPHERI C PARAWETERS; MEASL’REMENTS.OF 000TET1UM/HYDRO—c-EN RATIO

METHODOGOLOY~RECORDING-OFSOLAR ~ADIA— Sunif’ St that Sun

oass~d through Orientation1101 SPECTRA AFTER ITPASSED MARS ATMO Mars acmo- systemSPHERES DURING THE SPACECRAFT INGRESS IN sphereAID EGRESS FROM THE SHADOWOF THE PLANET

CONCENTRATIONSOF THE FOLLOWINGMOLECULESARE TO BE MEASURED:

Telescope03 7 — 25S no A/AR — 30002 7 • 760 nm A/Ax 10~

F120 A = OSO mm A/AX — 10~ Modulator

I-ISO A = 3.7 mm x/~ — ~ Diffraction

AS WELL AS THE DUST DENSITY Detector Detector grating

THE RESULTS OBTAINED WILL YIEL9 DATA ABOUT ~ 03HDOdetectorTHE ATMOSPHEREPHOTOCHEMISTR(t

0

3}I2O), H20ITS DYNAMICS (O,,HgO,dUSt),ITS ORIGIN AND PABEVOLUTION (HOC) D( ffraction

INSTRUMENT MASS IS 13 kg inter~eroineter gratingSPECTROMETER SCHEMATIC

Figure 17 SpectrcEnatryof the chemical calposition of the

Martian atnosphere-

EXPERIMENT ASPERA (FINLAND, SWEDEN, USSR)

00.2 E C I I V E:

— IC-N MASS COMPOSITION IN THE MAGNETOSPHEREOF MARS— TW,SEE-DIMENSIONAL ION AND ELECTRONDISTRIBUTION FUNCTIONS AND THEIR

MOMENTSIN THE MARS MAGNETOSPHERE AND THE INTERPLANETARY SPACE— STRUCTURESAND DYNAMICS OF THE MARS MAGNETOSPHERE

— MAG:JETOSPHERIC ECUNDARIES AND MAGNETOSPHERICPLASMA INTERACTIONWITH THE SOLAR MIND

METHODOLOGY-

MEASUREMENTSWITH ELECTROSTATIC ANALYZERSWITH

ENERGY RANGE: / IA,iMAGNETIC DEFLECTORSON A SCANNING PLATFORM / ~3i0I ~\ions O.S cV/q to 25 keV/q /elactrona 0.5 eV/q to 50 koW/q

Scanning +90°C)~APERTURE OVER 10 SECTORS 36xS

0 each (mechanical

~\‘B N E R G Y R E S 0 L U T 1 0 -N AE/Eiions 3%electrons 8% /MASS RESOLUTION M/AM>lO(for ions s,ith E<3kaV/q) ,,,._‘~‘~‘V~”t7~Zr, / /GEOMETRICALFACTOR (r.AE) z~’ \\~ /~ 2cr5 -sr.keVelectrons —5S 10 cm .sr. keVINSTRUMENT MASS 7:5 kg YZ plane

of scanningScanning aperture

and pattern

Figure 18 Studies of the spacep1a~nawith a scanninganalyzer.

The Phobos Mission (12)199

EXPERIMENT APV—F (cssR, ESA, POLAND, USSR)

OD U E C T I V C-:

STUDIES OF THE FLUCTUATION INTENSITIES OF ELECTRIC E5he,k,t) AND MAGNETIC

FIELDS AND OF THE ION PLASMA COMPONENT~1V (En,SV,e,B,y), AND OF THEIR SPECTRAL DENSITYS5,, Sn, SnV~

STUDY- OF COMBINEDWAVE DIAGNOSTICS HELPS IDENTIFY MODES OF PLASMA OSCILLATIONS IN THEINTERPLANETARY MEDIUM, IN THE MAGNETOSPHERE OF MARS AND ON ITS BOUNDARY.THEADAPTIVE ANALYSIS AND COMPRESSIONOF DATA ARE PERFORMEDWITH THE ONBOARDFREQUENCYSPECTRAANALYZER,

E’ IS MEASUREDWITH THE DOUBLE LANGMUIR PROBE.. 13>, - WITH THE SEARCH COIL MAGNETOMETER,

nV - WITH THE FARADAY CUP,S x

Parameter Me-isurenent Sensitivity Frequency

range (for lO

3Hz) range, Hz

~ s-5lO2(V.e~”I) lO6V.m1HzI~~2 lO~—3.lO~ n

1V

— ±~°~ 3.lO~

6flT.HZ~1/2 lO2.lo~n~v lO6A.rn2 1O9A•m~.IIz~ 1o_3_5.so2O~ ~ \~

SE. S

8, S~v ARE MEASUREDIN THE.1 to 10

3Hz RANGE \“\ ~ C

I WITH A REAL—TIMEANALYZER, IN THE Y-~ Y

FILTERS to i05 115 WITH A SET OP

INSTRUMENTMASS 7.3 kg ORIENTATION OF SENSORAXES- RELATIVE

TO SPACECRAFTAXES,X—AXIS IS DIRECTEDTO THE SUN

Figure 19 Studies of plasmawaves.

JASR 7:12—N

(12)200 R. Z. Sagdeevet al.

—1 —2 —3EOLfi.R fl:VELi:GAIION 10 1 10 10 7 mm

F -J fillsOonr o~c1irr~cit = 3~, 500 t.t.d 662 run o)~=5rim, Al/I 1O~

Ocleccopo — coronoErof ,

anc-le rc’aoOucLon 0. 17’

7-ray nnd UV — i:onitoring

bursts spccirm Detectnr t’oOu~.e 2 at GO cr-s

Detector volume 705 en3

lU7 lC-~ lL~ 1O~ ~93 cv

Figure 20 Studies of the Solar electranagneticradiation.

10 io2 io3 io~ 105 106 1o~ ~ ~, eV

— I I IEleotratatic lenses, spatial energy distribution

Scanning electrostatic mass—analyzer

G~B 21O’-~ cm2sier ICSV, ~E/E 0.03, ~M/M>1O

- Time.- oZ—flight M,E,q — analyze

G 8.1O~2 o~t2.stex~

Electrostatic analyzerG~.1O’~cm~.star

Solid state detector telescope 20.1 cm . eter

Angle scanning solid state detector telescope 20 0.55 — 9.2 am . ater

__________ I I I I10 10 2 io~ io~ io5 106 io7 108 E, eV

Figure 21 Studies of the solar wind and solar cosmic rays -

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