研究生英语阅读教程Unit19.ppt

研究生英语阅读教程Unit19.ppt

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UnitNineteen,SurvivinginSpaceByMichaelF.Long,NationalGeographic,January2001,Questions,1.Isitpossibleformankindtosettleinspacepermanently?

2.Whatkindofchangesarethepriceforthetickettospace?

3.WhatdoyouknowaboutthedevelopmentofChinasspaceflight?

Text,BoardingabusattheGagarinCosmonautTrainingCenternorthofMoscow,11GermantouristschatexcitedlyabouttheirholidayRussiasaerospaceholiday,whereyoutradecashforthrillsandspills.ThreemenreportthattomorrowtheywillhavearideintheMiG-21fighter（$4,000apiece）.Aslenderwomanwearingthickglassesandabuzzcutrevealsthatsheisgoingtodothecentrifuge（$2,000）,awhirlingdevicethatwillsubjecthertoperhaps5gs,orfivetimestheforceofgravity.Rightnowtheyreallexperiencingthe1gcommontoEarthlingsbutarelookingforwardtoadoseofzerogravity（for$1,500ahead）thatproducesweightlessness.AtChkalovskyAirForceBasetheyenterthehugecargohayofafour-engineIlyushin-76MOK.Thebrilliantlywhiteaircraftsurgesdowntherunway,enginesscreaming.,Rightnowtheyreallexperiencingthe1gcommontoEarthlingsbutarelookingforwardtoadoseofzerogravity（for$1,500ahead）thatproducesweightlessness.AtChkalovskyAirForceBasetheyenterthehugecargohayofafour-engineIlyushin-76MOK.Thebrilliantlywhiteaircraftsurgesdowntherunway,enginesscreaming.Ataltitudeasteep45-degreeclimbbegins.Brightlightscomeon,andthepilotsays,“Prepareforzerogravity”thenlowersthenoseoftheairplanetoproduceabout30secondsofweightlessness.Magically,weallriselikesmokeandfloatandflyaround.Justlikethat.Peoplewriggling,eyeswide,mouthsopen,facessmiling,frowning.Bodiesturningupsidedownastunningsightthatmyeyesrecordbutthatmybrainseemsunabletointerpret.,Duringotherzero-gravityperiods,oneofmycompanionsricochetsofftheceiling,Anotherdoesweightlessgymnastics.Anothertossesmearoundthecargobaylikeajavelin,twirlsmelikeabaton.Thisisseriousfun,asexhilaratingastheairbornemaneuversIvetaughtasanaerobaticsflightinstructor.Buttheslenderwomanwiththebuzzcutandtwoothersaresilentlyvomitingintoplasticbags.Theremainderofthegroup,whilenotovertlysick,seemtohavelostinterest.Theyareexperiencingthemotionsicknessthatafflictsmorethantwo-thirdsofallastronautsuponreachingorbit,evenveterantestpilotswhohaveneverbeenairsick.Thougheveryonerecoversafterafewdaysinspace,bodysystemscontinuetochange.,Deprivedofgravityinformation,aconfusedbrainengendersvisualillusions.Bodyfluidssurgetochestandhead.Neckveinsbulge.Facespuff.Theheartenlargesabit,asdootherorgans.Sensingtoomuchfluid,thebodybeginstoexcreteit,includingcalcium,electrolytes,andbloodplasma.Theproductionofredbloodcellsdecreases,renderingastronautsslightlyanemic.Withthelossoffluid,legsshrink.Spinaldiscsexpand,andsodoestheastronautasix-footercansoonmeasuresix-foot-twoandsufferabackache.Inanastoundingfeatofadaptation,Earthlingsarebecomingspacelings,andthoughtheprocessmaysoundterrible,astronautsadjusttoit,cometoenjoyit,andseemnoworseforwearatleastforshortmissionssuchasspaceshuttleflightsthatlastaweekortwo.,Duringlongerflights,however,physiologyentersanunknownrealm.Aswatched,cosmonautsreturnfromlongflightswobbly,pale,unabletostandwithoutfainting,needingtobecarriedfromthespacecraft.“WearecreaturesoftheEarth,”Iwastold:

“Thesechangesarethepriceforthetickettospace.Americansreturningfrommonths-longflightsonMir,theRussianspacestation,alsopaidaprice,sufferinglossesinweight,musclemass,andbonedensity.NASAgeareduptoseehowevenifhumanswouldsurvivethemostdemandingofspaceventures,amissiontoMars,whichcouldlastaslongasthreeyears.Manybiomedicalproblemscouldcompromiseamission,duringlongdurationspaceflighttheheartlosesmusclemass,whilethelargeweight-bearingmusclesofthelegsgraduallyatrophy,havinglittleworktodointheabsenceofgravity.Densityinsuchbonesasthepelvisandlegsrelentlesslydecreases1to2percentamonthonaverageaboutwhatapostmenopausalwomanmightloseinayear.,WaitinginambushbeyondtheshieldofEarthsatmosphere,solarandgalacticradiationcanpepperanastronautsbodylikemachine-gunfire.RadiocommunicationstoEarthandbackfromaMarscrewwilltakeaslongas40minutes,leavingastronautsprettymuchontheirown.Confinedtoaspacecraftroughlythesizeoftwomotelrooms,howwilltheygetalongwitheachother?

Andwiththemselveswhataboutloneliness,depression,andmedicalemergencies?

PreoccupiedwiththedemandsofbuildingtheInternationalSpaceStation,NASAhasnoMarsmissiononthebooks.WhenItalkedtoNASAastronautsandscientists,though,Isawthegleamintheireyes.“IdgotoMarsinaminute”saidastronautShannonLucid,holderoftheAmericanrecordof188daysinorbit.,“Theyweresurprised.Theytoldme,David,youneedtojumpin.Wewonderedwhyyouwerentjumpingin.SoIstartedtojumpin,andeverythingwasfine.”Wolfconcluded;“Whenyouunderstandtheseculturaldifferences,theydontmakeanydifferenceanymore.Buttheydomakeadifferenceuntilyouunderstandthem.”Apartfromculturaldifferences,psychiatristsalsoworryaboutthementalhealthofastronauts,includingdepression.Onesearchesforaquantitativemeansofrecognizingstress,mood,andperhapsdepression;“Wecantrelyonanecdote,whatpeoplearesayingonthewaytoMars.Weneedameasureofbehavior.”Computerscientistsaimtobuildacomputerprogramthatcanrecognizeemotionalstates.Alreadyacomputerhasbeenshowntorecognizesignlanguage.Thecomputersimagingsystemrecordsinformationintinypixels,whichenablesittodeterminesubtlechangesinexpression.,WillNSBRImeetDanielGoldins2010deadlineforadecisiononMars?

“Yes,wewill,perhapsevenbefore.Wereveryconfident,”saysLaurenceYoung,thedirectorofNSBRI.Young,whowasabackuppayloadspecialistona1993shuttlemission,looksfitenoughtoflytomorrow.Meanwhile,someofNSBRIsresearchmaybearfruitonEarth.Theinstitutehasmadeonediscoverythatpromisestosavemanypeopleatriskofsuddencardiacdeath,usuallybroughtonbyaheart-rhythmdisturbancecalledventricularfibrillation.Thiskills225,000peopleintheUSeachyear.RichardCohen,acardiologistatMITaridheadoftheNSBRIcardiovascularteam,explainedthatzerogravity“may”incitethisconditioninastronauts.Sotheteaminventedanoninvasivediagnosticdevicethatmeasuresextremelytinychangesinheartrhythmontheorderofamillionthofavolt.,TheseappetiteswerewhettedlastJunewhenscientistsreportedindicationsofwater,thebrothoflife,onMars.ButbeforeaMarsmissioncanhappen,expertsagree,thephysiologyquestionsmustbeaddressed.Gloomypremonitionsareafoot:

Asleep-deprivedastronautwithweakmusclesandbonesandaweakenedimmunesystemtakesaradiationhitenroute.Uponlandinghefaintsandbreaksaleg,whichrendershimhelplessandadistractiontohisfellowastronauts.Stressedintheircrampedquarters,thecrewbickeramongthemselvesandarguewithmissioncontrolbackonEarth.Themissionisthreatened.,Aworst-casescenario,tobesure,butthesethingscanhappeninspaceandsomealreadyhave.AttheMassachusettsInstituteofTechnology,astronautDavidA.Wolf,whospentfourandahalfmonthsonMir,toldaerospacestudentshowweakhewasonlanding.“Ihadlost40percentofmymusclemass,12percentofmybone,and23pounds.”Wolfsspace-adaptedbalancesystem,dealingonceagainwithgravity,gavehimtroubleturningcornersandhadhim“runningintodoors,”herelated.“Ittooksixmonthstofeelstrongagain,ayeartogetthebonemassback,andtwoyearstogetthedetailsofmylifetogether.,ThequestionofastronauthealthisofgraveconcerntoDanielGoldin,NASAsadministrator,whosaid,“Wedontevenknowifabrokenbonewillhealinspace.Togetanswers,in1997GoldinestablishedtheNationalSpaceBiomedicalResearchInstitute（NSBRI）,aconsortiumofexpertsfromadozenleadinguniversitiesandresearchinstitutes.NSBRIwillstudybiomedicalproblemsandby2010willpresentNASAwitha“go”or“nogo”recommendationonaMarsmission.,Earthlingswhoenjoythesunsbenignwarmthmayfinditsradiationtantrumsdifficulttobelieve.Coronalmassejectionsflingbillionsoftonsofelectricallychargedgasintospace,relegatingEarthsvolcanicoutburststomerehiccups.CollidingwithEarthsmagneticfieldinMarch1989,onesuchpulseshortedoutapowergridinQuebeclikeapowersurgefromalightningstrikeleavingsixmillionCanadiansmurmuringinthedark.SolarflaresexplodeonthesunssurfacewiththeforceofahundredmillionHiroshimabombs,launchingprotonstowardanyspacecraftintheneighborhood.,collidewith与.相撞；冲突；抵触Inrunningroundthecorner,hecollidedwithanotherman.在跑过拐角时，他撞上另一个人。

Iftheaimsoftwocountriescollide，theremaybewar.如果两国的目标冲突，就可能发生战争。

Nevertheless,NASAofficialsareconfidentthataccuratemonitoringwillwarnastronautsofsuchevents,sendingthecrewscurryingintothespaceequivalentofastormcellar,wherepolyethyleneshieldingwillabsorbtheradiation.Asecondkindofradiation,cosmicraysfromtheMilkyWayorothergalaxies,isamoreseriousthreat-possessingtoomuchenergy,toomuchspeedforshieldingtobeeffective.Heavyionssuchasironforgedinsupernovacantraveluptoafantastic185000milesasecond,nearlythespeedoflight.“Theresnowayyoucanavoidthem,”saysFrancisCucinotta,managerofspace-radiationhealthresearchatNASASJohnsonSpaceCenter.“Theypassthroughtissue,wallopingcellsandleavingthemunstable,mutated,ordead.Understandingtheirbiologicaleffect