漫游火星.docx

漫游火星.docx

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漫游火星

漫游火星

SpaceexplorationBeganwithdreaming,thousandsofyearsofhumansstaringintotheheavensandwondering,“Howdidthisbegin?

”Whatelseisoutthere?

Theearliestanswersweregiveninmythandpoetry.Nowtheyaresoughtbyspace-agetechnology,andwhileeachmissionincreasesourknowledge,italsoleadsourimaginationfurtherandfurther.Howdidlifebegin?

Didithappenmorethanonceintheuniverse?

TheanswermaylieonMars.Marstodayisdesolate,dryandbarren,andatfirstglancehaslittleincommonwithourownplanet,andyetfromorbitweseewhatlooklikeDried-uplakebedsandcanyons-cluesthat,threeorfourbillionyearsago,MarsmayoncehavebeenwetterandmoreEarth-like.AndsincelifeblossomedhereonEarth,thequestionis,diditevertakeplaceonMars?

Toanswerthisquestion,NASA’sJetPropulsionLaboratorybroughttogetherateamofscientistsandengineerswhosemissionwastodiscoverifMarseverhadwhatwasneededtosupportlife.AgeologistandastronomeratCornellUniversity,SteveSquireswaschosentoleadthescienceteam.Asprincipalinvestigator,hewoulddirecttheteam'ssearchforlife'smostessentialresource-water.（Squires）I'veworkedonthequestionofwateronMarsfor28years,youcan'tlearnwhatyouneedfromatelescope,andyoumustbeageologist,ageologistissortoflikeadetectiveatthesceneofacrime,somethinghappenedherealongtimeago,whathappened?

Wasitwarm?

Wasitwet?

Couldlifehaveexistedhere?

Thekeyisintheclues,andthecluesareintherocks,OnEarth,ageologistcanfindaninterestingrock,crackitopenwithahammerandjustlookatwhat'sinside,Butwe'renotreadytosendahumangeologisttoMarsyet,Sowehadtobuildarobotgeologist,andtheonlyplacethiscouldbedonewasNASA'sJetPropulsionLaboratory,wheresomeofthemostinnovativeengineersinthecountrywork,We’retalkingaboutarobot,aroverthatcangotoMars,landonthesurface,takealookaroundandthencutthecordandgo-carryingeverythingitneedswithit-cameras,instruments,communicationequipment,everything,Somethingthatcanlookinsiderocksandcantelluswhatcluesthoserockshold,Thisplacetomeisalmostsacred,Thisistheplacewhereourroversareassembledbeforetheyleavethisplanet,Everythingthatwedointhisroommustbeperfect,Over4,000peoplehaveworkedonthismission,Foreverysinglepieceofthisspacecraft,downtothetiniestone,therewasapersonsomewherewhoconceivedit,whonurturedit,whotookitfromaconcepttosomethingreal,it’stakenthisteamthreeyearstodesignandbuildandtesttheserovers,andwestillhaveworktodo,Wecanonlylaunchwhenthetwoplanetsareproperlyaligned,andthat'sjustamonthaway,butwestillhaveteststorun,We’reworkinginshifts,almostaroundtheclock,andwedon'tknowifwe'llmakeit,There'snoonepersonwhocangettheirarmsaroundthisthingandsay’sunderstandeverythingaboutthisvehicle,it’snowbursttheboundsofourbrains,ThisroverismorethanjustarovinggeologistThisroveralsohastobeaspacecraft,itactuallyhastoflyitselffromEarthtoMars,inaddition,ithastodotheverysubtleandquicktimingcontrolofallthethingsthathappenasitentersandlandsthevehicle,Wehadtostuffallthatintelligenceandcapabilityintothatlittlesix-wheelvehiclebacktheresothatitcouldgettheresafelyonitsown,lcallourspacecraftthe''origamispacecraft,’whichmeansit'sreallyacomplicatedseriesoffolds,Wepunchedholesinthelander？

thewheelstosnakethrough。

We'vehadtofoldeverythingintothesecomplicated？

getthissystemtofitinsidethis？

.It’sbeautiful,butataprice,andthatprice,inthiscase,iscomplexity.TherehavebeenmissionstoMarssincethe60s,therehavebeendozensofthem,buttwo-thirdsofthosemissionsfailed,Marsisaspacecraftgraveyard,Aspacecrafthastotravelabout300millionmilestogettoMarsatabout60,000milesanhour,butitstilltakessevenmonthstogetthere,TryingtohitourlandingsitesfromthatdistanceislikeshootingabasketballfromLosAngelestoNewYorkandhavingitgothroughthehoopwithouttouchingtherim,Thesmallestmistakeonourpartcouldputthewholemissioninjeopardy,TwoofthelastthreemissionstoMarswerefailures,Onespacecraftburnedintheatmosphere,theotheronecrashedonthesurface,Thistime,NASAdecidedtosendtwoidenticalspacecrafttodoubleourchancesofsuccessThetwo？

arenamed''Spirit''and''Opportunity,''Theyhaveverydifferentpersonalities,Theydidwhentheywerebabies,backwhenwewerefirstbuildingthem,’Spirit''wasourtroublesomefirstborn,Everytestweran,itseemedweranon''Spirit''first,andthefirsttimeyoutryitusuallydoesn'twork,We’druntestson''Spirit''andthey'dfail,andwe'dtrytofixthings,runanothertest,andthatwouldfail,too,Bythetimewegotto''Opportunity,’we’dlearnedstuff,andthingswentmuchmoresmoothly,Thebiggestproblemwasunderestimatingthesizeandweightofthe？

Oncewerealizedhowbigtheyreallyhadtobe,wealsorealizedthatthelandingsystemweplannedtousecouldn'tgetthemtothegroundingonepiece,Astherovergotheavier,thelandergotheavier,theaeroshellgotheavier,Thewholethinggotheavierandheavierandheavier,Fromtheverybeginning,onthismission,itseemedlikenothingwasgoingright,Theairbagsareliketheairbagsinyourcar,butwaymoreexpensive,Theyinflateexplosivelyaroundthevehicleandtheycushionthelanding,Thefirsttimewetestedthem,theytoreopenanddeflated,Setbacks-weknowtheyaregoingtohappenalwaystellpeople,whenyoustarttheseprojects,thesamethingprobablyhappenedto？

and？

intheirexploration–whatisguaranteedistherewillbesetbacks,3,2,1...Theparachutedesignwethoughtwouldworkrippedtoshreds,Thelanderhadgottensoheavythatthechutejustcouldn'thandleit,Wewerepracticallyoutoftime,andallwehadwasachutedesignthatwoulddestroythespacecraftwhenwetriedtoland,Wehadtobuildawholenothersetofnewdesigns–nolessthanthreeorfourdesignswehadtotestinthethreemonthsthatfollowedincurmadrushtomakeittothelaunchpadWewererunningoutofmoney,wewererunningoutoftime,Thedropwassuccessful,Thefactthattheparachuteexploded-notagoodthing,I’dratherhaveithappenherethan,,,Mars,That'sright,Unfortunately,strictlyspeaking,thatchutethatjustexplodedwasthechutethatwewereplanningontakingtoMars,Marsisatoughplacebosendaspacecraft,Theaveragetemperatureis60degreesbelowzero,itgoesdownto100belowzeroatnight,Therecanbeduststormsthatdarkentheskiesformonthsatatime,Butiftheroversmakeit,they'llgiveustheexperienceofwhatitwouldbeliketobeonMars,We'llbeabletolookoffintothedistanceandsay,''Yeah,I’dliketogothere,''andthenactuallygoandseewhatwefind,Therover'sarmhasthesame?

ofahumanarm-withashoulder,anelbowandawrist,Thearmtucksuptightunderthefrontofthevehicleforwhenwedrivearound,butwhenwegettoarockthatwewanttoexamine,thearmunstopsandreachesout,usingallofitsjointstoplacetheinstrumentsonarockandtobegintostudythem,Thehandhasfourfingers,Oneisamicroscope,twoare?

totellusingdetailwhattherocksaremadeof,andthefourthoneiscalledtheRAT-theRockAbrasionTool,Toexaminetherocks,we'vegottogettothem,andMarsisverybumpy,Sotodealwithbumps,engineerscameupwithasomethingcalledthe''rocker-bogie''suspensionsystem,it’saverycleverdesignthatallowseachofthesixwheelstogoupandoverarockindependentlywhiletheroveritselfhardlytiltsatall,.“OK,comeon,guys,Now,stayandwatchit,watchit,Stayclearofthis,'causeit'sgonnamove,OK,watch,watchthewheels…”itgoeswaybeyondthissinglemission,TheeventualgoalistosendhumanstoMars,butthefirstpersontowalkonMarsisnotanastronauttoday,it’ssomeoneinhighschoolorinelementaryschool.“Soit'sturninginplace,then,whenitgetslinedupjustright,we'regonnadriveitbackwards.”We'veinvestedsomuchwork,somanyyears,somuchofourhopesandourdreamsintotheserovers.Andthenwhenyouthinkaboutwherethey'regoing,theridethey'regonnagetonthatrocket,thetransitthroughspace,whatit'slikewhenthatparachutegoesoutatmach2,goingthroughtheMartianatmosphere.You'restandingnexttothislittlerobotandyourealizeit'sgonnaspendeternityonthesurfaceofanotherworld,it’sgoingtoanotherplanet,forreal.Andoncethey'regone,that'sit,Aftertheroverslaunch,we'renevergonnaseethemagainwithourowneyes,We'vedoneeverythingwecantoprepareforthedangersthey'llhavetoface,butit'sgonnabeveryhardtosaygoodbye.''Spirit''willbelaunchedfirst,andthen''Opportunity''threeweekslater,MarsandEartharebotharoundingthesun,sothey'realwaysmovingrelativetoeachother.Every26months,there'sabriefintervalwhentheplanetsarelinedupjustright,Atthattime,andonlyatthattime,wehaveenoughrocketfueltomakeit,Sothisisouroneshot.5，4，3，2，1...Wedon'tfirearocketmotorallthewaytoMars,Wedon'tneedto,WejustplacethespacecraftonatrajectorytoMars,andletitcoastfor7monthsand300millionmilesuntilitreachestheplanet.“Onceit'sbeenpushedonitswaytoMarsbythelaunchvehicle,.ithastomaintainitsorientationtowardthesun.Soallthathastotakeplaceoverthecourseoftheseven-monthjourneysothatitwouldhitMarsandgettothisverytinyspotonMarswe'reaimingfor,andi