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1、Unit4Safety,Maintenance,andQualityControlLessonsTeamProjectReviewAdditionalResourcesEXITUnit4Safety,Maintenance,andQualityControlLesson1.WhatcausedtheexplosionLesson2.ThepreventionofaccidentsLesson3.WearingspecialclothesLesson4.TheamplitudeofmotionLesson5.Qual
2、ityandafinisheditemLesson6.A“totalqualitycontrol”approachEXITUnit4Safety,Maintenance,andQualityControlAdditionalActivitiesReadingResourcesWritingResourcesUnitTestGrammarResourcesAdditionalResourcesEXITLookatthephotographbelowand,inpairs,answerthequestions.Less
3、on1Whatcausedtheexplosiona1.Whataccidentdoesthephotographshow?2.Whenandwheredidthisincidenttakeplace?3.Whatcausedtheaccident?4.Howmanyliveswerelostintheaccident?Skimthroughthetextquicklytocheckyouranswers.bNASAspaceshuttleconsistsofthreemajorcomponents:awinged
4、orbiterthatcarriesbothcrewandcargo,anexternaltankcontainingliquidhydrogen(fuel)andliquidoxygen(oxidizer)fortheorbiter’sthreemainrocketengines,andapairoflargesolid-propellantrocketboosters(SRBs).OnJanuary28,1986,theChallengershuttleanditscrewofseven(includingte
5、acherChristaMcAuliffe,whohadbeenselectedtobethefirstprivatecitizeninspace)weredestroyedshortlyafterlaunchfromCapeCanaveral,Florida.TheprimarycauseofthelossoftheChallengerwasthefailureofanO-ringsealofajointononeofthesolidrocketboosters.TheSRBsareconstructedinfo
6、urcylindricalsections.Thesehavetobesealedtogethercompletelytopreventtheescapeoftheextremelyhotby-productsoftheburningfuelduringalaunch.TheO-ringsarerubberringsthatplayavitalpartinsealingthejoints.AOnthedayofthelaunch,theweatherwasunusuallycoldandthiscausedther
7、ubberofoneoftheO-ringsonthejointbetweenthebottomtwosegmentsoftherightSRBtobecomebrittle.This,combinedwiththefaultydesignofthejoint,allowedhotgasesfromtheburningsolidrocketfueltoescape.ThegasesandflamesburnedthroughthemetalthatheldtheSRBinposition.WhentheSRBbro
8、keoff,itrupturedthesideoftheexternalfueltank.Thisallowedtheliquidhydrogenandoxygentomixprematurelyandthisiswhatcausedtheexplosion.Readthefirstparagraphofthetextand,inthediagram,lab
