Moore on Mercury: The Planet and the Missions PDF
Preview Moore on Mercury: The Planet and the Missions
Moore on Mercury Bythe same authorfrom Springer: The AmateurAstronomer (12th Edition) PatrickMoore Astronomywith a Budget Telescope PatrickMoore andJohn Watson The Observer'sYear(2ndEdition) PatrickMoore The Sun in Eclipse MichaelMaunderandPatrickMoore Transit: When Planets Cross the Sun MichaelMaunderandPatrickMoore Eyeson the Universe: The Storyofthe Telescope PatrickMoore PatrickMoore's MillenniumYearbook PatrickMoore andAllanChapman Sir Patrick Moore Moore on Mercury The Planet and the Missions With 82Illustrations ~ Springer Coverillustrations:Clockwisefrom bottomleft:BepiColombo(image courtesy ofESA),Messenger(imagecourtesyofNASA)andMariner10(image courtesy ofthe JetPropulsionLaboratory).Backgroundimage ofMercurycourtesyof NASA. BritishLibraryCataloguinginPublication Data Moore,Patrick MooreonMercury:theplanet andthemissions 1.SpaceflighttoMercury 2.Mercuryprobes 3.Mercury (Planet) I.Title 523.4'1 ISBN-13:9781846282577 ISBN-I0:1846282578 LibraryofCongressControl Number:2006931930 ISBN-I0:1-84628-257-8 Printedonacid-free paper ISBN-13:978-1-84628-257-7 ©Springer-VerlagLondonLimited2007 Whilstwehavemade considerable efforts to contactallholders ofcopyrightmaterial containedinthisbook,wemayhavefailedtolocatesomeofthem.Shouldholderswish tocontactthePublisher,wewillbehappytocometosomearrangementwiththem. Apartfromanyfairdealingforthepurposesofresearchorprivatestudy,orcriticismor review,aspermittedundertheCopyright,Designsand PatentsAct1988,thispublication mayonlybereproduced,stored ortransmitted,inanyform orbyanymeans,with the priorpermissioninwritingofthepublishers,or inthe caseofreprographicreproduc tioninaccordance withtheterms oflicencesissuedbytheCopyrightLicensingAgency. Enquiriesconcerningreproductionoutsidethosetermsshouldbesenttothepublishers. Theuseofregisterednames,trademarks,etc.inthispublicationdoesnotimply,evenin the absenceofaspecificstatement, that such names areexemptfrom therelevant laws andregulationsand thereforefreeforgeneral use. Thepublishermakesnorepresentation,expressorimplied,withregard totheaccuracy oftheinformationcontainedinthisbookand cannotacceptanylegalresponsibilityor liabilityforanyerrorsoromissions that maybemade.Observing theSun,alongwith a fewotheraspects ofastronomy,canbedangerous.Neither thepublishernor theauthor acceptanylegalresponsibilityorliabilityforpersonallossorinjurycaused,orallegedto havebeencaused,byanyinformationorrecommendationcontainedinthisbook. 9 8 7 6 543 2 1 SpringerScience+BusinessMedia springer.com Acknowledgements My grateful thanks are due to Dr.David Rothery, of the Open University,for his invaluable help when this book reached the proofstage. My thanks are also due to John Fletcher and Peter Paice for theirphotographs,andto TonyWilmotforhis drawings- andto NASA,JPL,the IAUand the LowellObservatoryfor allowing me to use their material. PatrickMoore July2006 v Contents 1 Lift-off . ... 1 2 ElusivePlanet 5 3 "Messengerofthe Gods". . . .13 4 Mercuryin theSolarSystem · 21 5 CrossingtheSun . · 27 6 Ghost Planet. . . . ... 37 7 Throughthe Telescope. . . 47 8 MappingMercury. · 55 9 Mariner 10.. . . · 65 10 CrateredWorld . 73 11 AroundMercury . 85 12 Returnto Mercury 105 13 Lifeon Mercury? . 115 14 ATrip to Mercury. 119 15 MercurianBase 125 Appendices 1 Data for Mercury. 131 2 PhenomenaofMercury . 133 Bibliography. . 135 Index..... . 137 vii Lift-off In the early hours of August the third, 2004,a group of people waited expectantly at Cape Canaveral, in Florida.Most were scientists, though some were reporters and invited onlookers. Allhad eyesturned toward the launch pad,asafedistance away. In it wasatall rocket, carryingone of the most interesting space-craft of the newcentury: Messenger,bound for the little planetMercury. Manyvehicles had been sent to otherworlds;some hadbeen successful, others not, and certainly there had been major developments since 1957, when Russia'sSputnik 1ushered in the SpaceAge.Sputnik was no larger than a football, and carried little apart from the radio transmitter which sent out the "bleep! bleep!" signals which will never be forgotten by anybodywho heard them (as I did).Sincethen almost all the attention of the space-planners had been focused on the Moon, Mars, Venus and the occasional comet, and only one probe had been sent to Mercury.This was Mariner 10,which had made threepasses ofthe planetin 1973-74before its transmitting power gaveout. Mariner 10had been a great success,but it had been able to imagelessthan halfofthe planet's surface,and wehad to admitthatmany problems remainedunsolved,sothat ourin-depthknowl edgeofMercurywasdecidedly sketchy.Messenger,itwashoped, wouldtell us much more. The last moments before launch were tense. Lift-off had already been postponed once,mainly because of cloud-cover at Canaveral,but this time allwentwell."Four... three ... two ... one ... Wehaveignition!"Therewas Moore on Mercury:The Planet and the Missions Figure 1.1.The launch ofMessengeratCapeCanaveral on August 3, 2004.Images courtesyofNASA. abrilliantburstoflight,followedafewseconds later byadeafeningroaras the rocket rose from its pad - slowlyat first,then more and more rapidly. Messenger was on its way. Soon it was lost to the view of the waiting onlookers.Four minutesinto the journeythe firststage ofthe launcherfell away,andthe motorofthe second stage ignited toputthe vehicleinto orbit round the Earth.The onlookers breathed sighs of relief.After a 37-minute "coast"phase, the Delta-2boosteragain firedfor three minutes.There was abriefmanceuvre, and the probe separated from the rocket; henceforth it 2 lift-off Figure 1.1. Continued was on its own.The whole launch procedure had lasted for just under an hour. The two solar panels were deployed, to generate power, and the batteries were switched off.The five-thousand-million mile journey had begun. Messenger - acronym Mercury Surface Space Environment and Geochemistry and Ranging - was in no particular hurry. Its Boeing-built Delta-2launcherwasnot powerful enoughto send the probe directly from Earth to Mercury,and it wasnecessaryto use the gravity-assist technique, 3 Moore on Mercury:ThePlanetand theMissions involving one swing-by of the Earth, two of Venus,and three of Mercury itselfbefore the probe finallysettles into Mercuryorbitin March 2011.Itis rather like driving from Brighton to Bognor Regisand making detours to Winchester and Hull,but there was no alternative, and the technique had already been tested and found to be satisfactory. Oncein orbit, Messenger wouldspendwelloverayearcollecting andtransmittingdata before being deliberately crash-landedon the surface ofthe planet in 2015or 2016.This would not be a controlled landing, because this part of the original programme had to be abandoned on financial grounds. To President George W.Bush,Messenger was much less important than the attack on Iraq. At least a great deal could be learned from observations made from orbit,and thespace-plannerswereconfidentthat thefullprogrammecould be carriedthrough,even though it did mean ratheralongwait. Figure 1.2.TheEarthfrom Messenger.ImagecourtesyofNASA. 4
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