Created: 12/1/1989

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Oirrclortu o' [pi'lUinx*

Soviet Optionsanned Mars Landing Missior

Soviet Optionsanned Mars Landing Mission

Seniel Optionsanned Mai* IandiiiE Mission


believe Ihe Soviets arc planninganned Mom landing minion some lime alter ihe0 Allhoueh wc believe Ihe mission hai noi bees officially funded, ihe Soviets have invested in (he mffailiuciiiie and are engaged in ihe long-lead research and deveopmeill necessary for its conduct, dear indications of Soviei intent io per formission include:

Continuing: long-duration flights aboard the Mir space station thai have relumed following ihe recent short-terra hialut in manned activity.

The probable development of nuclear rocket engines.

A planned program of unmanned flights io Mus over the nestean, despite last year's Prtobos failures, giving Ihe Soviets data for in attempted manned mission.

An increasing number of press releases by Soviet scientists, engineers, and cosmonauts discussing their intent toanned mission.

The Soviets have several available options in mission profile and spacecraft design lo aeeomplish this million. Balancing the technical demands of each option with the strengths and weaknesses of thecr space program leads us to believe ihe Sovieu are most likely to pursue:

An opposition-ctais mission profile, where Eanh and Mart are near their closest approach at the time of arrival at Mart,enusto reduce energy rcQuirementl.

Either nuclear Co conventional engines siting cryogenic propel Itefficient spaeecrafl propulsion.

Ar-rohnt-ing into Mars orbitto reduce Ihe propel la nt requirement.

Because of ihe siie and mass of theanned Mais landing mission wilt require vehicle assembly mEarth orbit The Soviets have the Enct(iya heavy-lift launch vehicle in place Ihe components into low Earth orbil. In addition, ihey wtllanned space station to support spacecraft assembly andpace tug to move large components into position for assembly.

Weull-scale, manned Mars landing mission is unlikely without development of an on-orbit cryogenic storage capability and cither nuclear engifretoraerobrakine techniques If theSovieis use nuclear engines with) liquid hydrogen propellanl, it would substantially icduce the number of

launch vehicles requiredlice spacecraft eompcmenU in low Earth ecbit. The use of cryogefucs will requite the developnsenl of advanced on-orbil refrigeration and iaiulalroi techniques to maintain the propeUanlaiquid state and reduce their loss because of boikiff. Aetobtakinjr into Mars* of bit would reduce the mass of raropeUanu tcctuiitd in low Eattb of-bit by as much asercent. This would allow the Sonets lo use proven conventional erigines with liquid oxygen and liquid hydrogen propeHantschieve roughly ihc same reduction in (he number of launch vehicles needed to place soacecraft components in low Eanh orbit as with nuclear engine

We believe (hat, if the Soviets proceedanned Man mission, they willooperative effori with ibe Untied Slates to defray some of Ihe high cosl. Cuirent Soviet estimates range frombillion USfor even the most economical launch opportunity

Rectal publk atilunenls by Soviet offlculi havel iIji the Sovieu are continuing researchnsii bli manned Man mlssaan laoviet apace scarav.kaist-oe ivmposlum cull "ltd lie fcaMaaini koagtrirn Soviei Min apace iBanam:

the bunchan aad lunar-polar evbitci2

The Lauachpaceeraft to Man. iieludiaj aa oebhu. nrwrpbriH baDaoa. and/cr sea!4

Man simple return ntutaMnaaer

A manned Man0.

lie tscceisfol ecunplclioa ol unmanned mauionifive the Sorieti valuable data on iputecrafien-orbit lifctimri. landing irlea on Mart, and com im ad ind conirol ol* interplanetary spatocrafi DetpiitiheScniiti' rectal failure toeompkic their Phobotelitvt (hit theyapply Ihe lessons learnrd and punueminnci) Man rrvntion

The Sen ieu altoed publiclyhe long-term cJTctli of weighllessaeu Co bumint mail be fully understoodanned millionan can be accomplished- Soviei cosmonauts have been in tpiee cent inuouity for up lo IWdiyi Vladimirreu toasminder, and Muia Msnarov, flightuert on board ihe Mir spate ilatVon from 71



T Ihroagh II. (tbey exceeded Iheay record, held by Yury Rcmancnko,on II Novemberami became tbe fourth and fifth cosmonauts to accumulate moreear ine believe that the Sovieti willinnti' ibiion of IS monthi or longer within the nen few yean. Continued long-duration Stays in ipaee by Soviei cotmouati (not requires for scoce-station Opcriiiontl and plaaaed unmanned mil-uom to Man ire our urcig ci indieaton ofSoviei plantanned Man million

I Man Mitiia'

anned aaiiiico lo Manornpiei ting. Basic minionsls irsdoile:

Definition of million gab.

Sclinionieich date (diettied by orbital mechanics).

of the type of propultionei(>iflesign of (he ipacectaii

o( imouit and type of vatnliric eq.ip-ment carried oa the spacecraft.

Changes io any ol ihese requirements could change

the mimon

itlom Camieticdiaard Marl Million An irticle in iheedition of the Eoeytlosedla of Coi-ioieur.'cianned Mart million ii lining onealf to tuo yean andi engines and liquid tjdrcgen propellani.pecific impulseecondsotal mist on orbitsttrie tons. Our



tlip- HniCJ

assumptions were based ia part on (his article.ssumptionstaken from US conceptsanned Mars mission;Crew ofor sii.'

Mars spacecraft assembled in aid departing from low Earth orbit with space station support

Nuclear engines using liquid nvdiugea rveeeUnlee) Or conventional engine* using liquid cuygen and liquid hydrogen rncvdlints (lip aV)

Venus swlag-by to reduce energy reqtnreerienis.

Mission module, to remain in Man orbit, wlilrs weight0 kg.1 kg return weight for Earth reentry module.

Marsoduli to transport Miri linrliag crew and equipmentnd from Mars surface. The module's weight wiltg. plus an addluoig for nuclear shielding.

Required velocities achieved by three propulsion

structure factor far auclear cngiaes using liquid hydrogenercent; conventional engiees using liqiiid otygen and liquid hydrogenercent

Elliptic capture orbit at Mars and Earth.

Mart Mission Opportunities

Opportunities for direct flights to and from Mar) occur near the Birth-Mars coeoiition, appraiiinilely everyonths.general classes of ctirtci round trip mission profiles lo Mars are available:

Earth and Mars

a re near their closest approach al the lime of arrival at Mars,hort stopover lime al Mars.

Earth and Mirs arc farthest apart at the timears,ong stopover limt at Mat,

i of the eccity cu* Man' orbit, the million prohle changes from one ccoosition to the nett. The minion profile variation It cyclic, and the pattern

irvof bi vaitmiard as Uc the epirreun sin reqrrrcdrnanrci! Mart tniuiia. Aftbiaafc latere* Wroris i*

radiAtf.anUilimraitntMv-srni'rf* prasasay *nal count al aliSt uiiurr.iad mnwtlaa uacUMii aljliillyiStiin. We flint ilat at Iran ikm (icumenamnd Iran the luifice a* Man ia in

raiwiSa* nwdilt vKti ire ottariauioiln* <

remain hi nrtli irwbl Mmmvtm nodal repealsears or every seven oppositions Tbe relative positions of Earth axd Manhort stopover lime atoays) require execs-live energy for the spacecraft propulsion stages toirer*ip mission To reduce the energy requirement foe an oppmltion-clais mission, ihe gravity held of Venus can be used either en route to Mars for an outbound swing-by or en route to faith fee an inbound swing-byission lime for in opposition -el sis mission sntl varyays. Energy requiresssenls can be reducedoaj unction-class mission because low. energy, near-Hoh ma on-type (minimum energy)can be used on ihe ouibound and inbound nipt ending the staytimc at Mart appropriately (JaDotal mission timeonjunction-dais mission will vary from approilnuielyay:

Thereide range of mission optical available, for the purposes of this paper, we willoviet manned Mars missionday siiytime on the surface of Man and will use aa opposition-diss missian profileenus swing-by to reduce total energy requirement! (wc figureitaonvent tonal and nuclear prrcpubion. including the cfTcds of acrobraVIng at Man and Earth, areThe total on-orbil mass of the Man spacecraft and the number of launch vehicles required to place the necessary eomponen" it la low Earth orbit are determined for each cast.

Man Spacecraftrationale

There arecton for deierrJning tpaecciifi mass on eehit. These Include the propulsion ly.icm, spacecraft design, launch opportunity, and crew site We calculated the total mass required on orbit roe tbe Soviet Mart itoce craft assuming three propalsion stages were used lo conduct the mission from low Earthhe propulsion options we eiaminod were:

Conventional *agincs using liquid oiygta and liquid hydrogen in all three slagel


Typical Minion.Stopover at Mm

i Mia t mh



/ /

/ / / ara-

V m

^*S^ Mm arrw


nilnn mini lioflid hydrogen In (II (hire iligei

int liquid hydeoten in the fini ind iccond illio. id" conventional encines utinind lie-aid hydrogen ia the thitd ante

fot each Option, Calculatioei -ere made for;

All-propuliive raaneuveei fo* all phnej, inchadine Man cotry and Earth reeetiy.

AerotoaheatEartkeceartry.wiihMr^ vert propuhivc.

Aerobrake at Man entry, with rewtaininr mineu-vera propubive.

Acrohfake at Man eatry and Earthiih reeaainine naneuveri piopultive

Weyeari JtMl andan ce-poaatkn-clati miuiu for ourhe da lei rcoreicnt the approinaiic wifcmum- and miiimunvcncrry requirement! for 'ekcled future oproaitieavefan,ac-by launch opporiunitlei (tee appendi-J

Man for the different eeaieei for all-propuliiveranrcei from appraajanaadyk|eiobrakioj at Mart could reduce the man retirement byo iSependiat oa the piopuliion option and bunch date chosen. I* fact, acrobrakint ai Man -ouldajor ia-.pact on the number of launch .ehielei reoulred to place Man


Total Matt oa orbit andl launch vehicle,




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irk rwmser el tnaack vauckiio aim cantm mi ia ii-cartaa ltd by .uimiii <bii im hllvkni iojjtoi*ciin mtux-netluia krmti ulmn ul. ih*-oavs d* lurkcirai io carry aceyjxq tri al lltqid bjdrefca (baton al at* urae tin nil -oild uidf eihj ii<ico.cco laainab alrf* tht ailueicmsff.ld lihminii wrnaby il.ard ihai wit -itnriamr uiixb nhll nguuiniau

cumponenti in low earth orbil. eipeeiailj fluiini tauaeh opponacdties with hither ruxrjy re-

ik* ubttt the rturnber ol* llararji vefrvjel

rofaatd tor all rrrraaelirae mane-raviroaa is so| al mart, ko-tver. red urea launch

'rrncro: !estiib nffor any propulsion option chosen al aay lauach raji lunity. tlrii sifnirvciat reduction -ould matt previa conventional anfints with liquid oiytfii and liquidan attractive oca ion. elianinannf itie need

for nuclear oifinci art? tctiCtfJl rnduluan ahicld-rn* for crew proem m

cefcaltlrom forf ait and three woe pet-formed an! anal/red todesermine ihc impact on total sr-acte-rafl mass depending on th* launch cot>.'iu-.iy

'ili.;rT iyiieiEed'-el ion.

sii* from sit la three wouldavinji of 5peieent of themass required in low

ib.- trnamutt intaviaai ot am* uakaaet wbescl b, taantiruj only fannil'iiviu. in*iu lianca vajuclet

buomea aa* to mree. tbeae icsaltant linnpcooi-sered minimal when compaied to the advanueri

oftoided by ike larter tie- "id ire notaned in this



serial months uoald be icquitcd lOOlbit Hi ihe necessary components (exMarsoday turnaround lime Tor each tauechpad.

Mannar) Mm Million Reaulrcmcots

A Soviet manned Man mission win involve Ihe development of key tcchnolofics. These teen notese of twothat will be required for Ibe Sovieu toanned mission and (lose Ibai jrill cahance the Soviet ability to conduct ihc minion

Key Technologies Required forManned Mars Mtsile*

The required key Icchaolcgata arc;

Heavy-fin laanehveBaelefHLLV,

stirion oae cr/maici

Oa-etrbti shelf bit of spaeacrift etartu^tarj.

Lde xSencei and

Orbitalehiok |OMV

omotil t'rMilr An HLLV will be rt>lat* piopellants ind spacecraft ccreipooenis in low Einh orbit. Ihe Soviets lucccaslally bunched an Energiya HIay IMT and. The vehicle is capable ofM.COO-kilogram raykiad in low Eanh orbit and should be fully operational by theO. C

Spoti Sutioo on (VtM To luppon luoabty af tbe Manpace station oa erbil will beTh* Mir raoovLar space uaiiom now is e* xfau ind could aoppect the ccuMtruciKuiats intent aft The Scwirta already have announcedarjei modular ipaca nation, which weobe launched in16me.

Spoordvanced refrigeration andtechniques will be required to prevent eicess loss ofcryoienic propellatits caused by bouoff. Handling and storaie of these proprllaou alsoajor

problem beuase net in-flight refuelingnvisioned durinrr the mini an The Soviria have sometcb and boand hydroeea iaHLLV. Thtaai Ml to be aortd for oatr three yeanaenrd

Man ir in.

Oo-OrUi SitIU' of Sptttaifi Compotrm. The Sonets have more than five years of eapeiience with theoaet stations.emains on orbit. Rffamdaaf tahkuoual lifetime da ta. and acUitrcn-al carperrcac*be rained with the Mir space stitian Thr Soviets have dcmortilrated increased lilctime with iheir manned spacecraft by ha vine etewi on beard to repair and replace component

Life Sfintn aad Support. Long-duration flirt hisations are proviriiag touch el*

ihc data aamtiryuk* taaatlaual latajroi liTxe'J ia

ihe "tarena. Tbe hamafat ctTocti of weight-lenoeu contmut toajor concern. Soviethave performed oonlinuoai Ipacefliiht in eicestear. We believe thai thei will increase the duration of ipaccon maraomgi in Increrncntieriod ofrears One or mete two year million may be iieeded lo fully indctiiaBd the aacdacal1aaruted Man niaaaav Aeeordrpc to Soviel coeat laurca. rTadipta'Jonravity tVctd normally lakci place within several days, bait, in acme eases, sevcril weeki may be required. However. Ihe

abilityoimaniat la perform nib unaided by 1

(round ere- immediately after long upnsurc to wtichilcuneia is eutstroraablc. Control of erone-calci-

let. era Itaulduillaaa raattuaoa alsonot ud

-aoeruood br US ea So-iet rvaenrtawn andaajee ninethei Stud

nfairavtr'as Vi&tU. An OMV, also knowspace lug. -ill be required to move large component! cf the Man spacecraft into place for

- -i1 M'eanoa orb:

ThenyVnaa raaadak to aceaaa-

docking of the Kraal apace nation

modulemay be intended

for use MIR OMV

Key Tl-hailieies Thai Winanned Man Mtuac*

Ktyag ia that wiB cabinet Sever eforit lottWHl Man rrniraan arc


Cloned (tolniicil nrt-i.

ArliVill (ra-ily

AiirbiaUii. Acrobrakin) inmlves atmosphere to dissipate an entry vchido't energy ind reduce tittered Acrobnking can be Medhange oibii or to descendUwi'i turfite unicad ol

.urtlirei-.tii Aa calry achat I-

eaubieifl Ilhii teaiM be tkaprd lilt

lb* US Apoflo or Semet Soyw entry naodalol thai

tialrrtjy low blVia-drag raid The tnir* acrlick'i tntriy Ibeabe dim pa tad through ablaiHHi of lb*

Aninio Mara orbit atarld rtduee the of propellanji required ia low tanh eahil by at at ii peroem (tee figure

JThe Sonets have ilated thai liny inteed lo UK"on ibclr unntanned iri>ow. and ihry do bur scene riperitnee aiith atyubraking cc earlier Man irniaaoai. The Manalindandtr mixaana uaad an atroaWJI hrakina oVvee. although it dad an (tataati aay hft

Ntltmtcinar tafta aa-ag aaaaidpaotaJUat taaU pte-idt alraaat in the

hp of cwvcatieauluaa* eayge.urd hydrogen aaiatur* The iraerraied lap

rcdutc the amount of prcptllani and the total man required onuclear eminc alto ccuM provider for the Manrime Ihe


The Se*ieii nay be itnita adrintcd icactori toitand


S toaftranti held tartiei that year on ipaee nuclear powe*oviet icitntoiaper diituuini nuclear clrcirK prccyubleai(NEP)at one of atcu una btia| in*eaii|itcd by the Soor usean rnitaaon for elccincalnd pi opal ikm MFP vaoaMigher lap. batlover thraw krveh NfP engines voild probably bt dciienrd lo bar* toniitiuouily. aid ibe ccanpara-thc roaad tripanaan aaiqiaaiacrtue liaaibeanaly. ailing NEPcarvae ate am dCMible far carry auaaed mum

Oaxdfllaud cca-saveal ayirera ceaJd provide lifi lappori caaaaaabkafaad. aad viler, inert by cl<tnaaatiac serai of Ibe mail of eiptndabU:leatd svittm will have mammal inapaci on the local aunaocr of banco,required loiuaon. however, becauie the matt of eipradaole tonsumiblc* cressiitutcinstil fraclion of ihe total man reoairtd Soviei total nit nfre working on cloud ccDlocieal lyitemi and hive mudsystems -ill be uttd on fmurr i

Anifittal Gittiif. Ihe long-duration effects ofart noi fully understood, and counter-measures are continually beini impkmenied lo re-duct ihe period of rcadapiaiion to iraviiy. Theof Man ii about oat third that of Earth's, and scientists jenernlty belrevt ihil humaninible to adapt rapvdly to tu iraviiatienal field fonenrin.period) of aei[hileiineii en route. Tbe Scicil ate inreilitaiinc the paulbte ate of artificial traviiy. There are diRcrcncet of ceanioa ia ibe Soviet Ucca. juit at there art in the United Stales, on ihe benefits and enfinctrina nade-olfi required to Ineoe-poriirartificial gravity fichl on the Man ipace-

go >Veil)anned Mar* landing mission- We prevfct. however, ihal tbe overall manned spare effort will remain robuti. ai least (or the nut Sic rears as the Soviets add new modules lo ihe Mir spaee station and ai tbe shuttle or biter becomes operational. In ihe middle-lo, the cost of manned space activi-lies cos Id increase if ihe Soviets proceed with pinesed Vow-on apace station.

Sovki spacend orhciab have been trying to deflect Soviei dtieitm of ihe en or mens eapense of aetce activities by stressing the economic benefits lo the national economy For tjsmptc, (be Soviets dlim that tn sitcomlng Mir module will produce profits that will pay foi ihe project many limes over. Other claimed benefits from ihe space station iiscfudcag.'seaiiural production, enhanced reforesla-ton programs, aad increased harvest by fishing Recti.

Cooperation With Ihr United balesan Mission.

The Sonets mayto coocarai* with the Untied Stairs, which asanned Mars nuuion. so defray some of the it pease ofaasM. Sranet soecurs bow art pursuingooptraine eSorr. a* the Uwied States dnidaa not ta participait because ofaaaftr nsamarrstiaan or fat other reason, Ihe Sontii are likely iaanaed Mars mania* oa tbetr own Tbey would

pftrhlFif atttmpt la gun griattr eaoptratioa sad

financial support flam France and prihspa other nitaxis that have town or participated 'a cooperative

eflont on Stmi ipace station

Foture Indicatorsoviet Mission

Future developnseats that would indicate continued progress inward realising tbe mission include:

Deveaopanent and use of aerobrake tcchniquci.

Advaaced refrigeration and insulation on up&rning tJBtnanaed space missions.

Assemblyars spacecraft prototype in tow Earth orbit.

A flight to Mars of an unmanned prototype.

The possible flight testinguclear engine

A manned Mars mission most likely could not take place Wore the0 because of ihe lime required lo develop aerobrake techniques, nuclear engices, advanced on orbit refrigeration, Improved insulationully operational HLLV, andoted-cyclc. life-support system. If Ibe SovicU are successful In developing gerobraking tech. niques. the most Iskdy option woo Id be lo use proven conventional enginea with liquid bay gen and liquid hydrogea propel la nts. Without aerobraking, nuclear engines probably wild be used in ibe mission lo reduce the number cf launch vehicles required.aerobtakiag or nuclear engines,ryogenic On-or bit storage capability, we believe it is unlikelyull-scale manned Mars landing mission could be accomplished Using storable propetlints, which have fewer lips, wouldrohibitive man on orbit. Such use probably wouldanned rrussion nearly impossible, especially dufiag launchecessitating higher energy requlre-meitj*.


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