review/reduction ofthisdataallowedtheestimationofthenumberofstickingevents,thelocationswhere theseoccurred,thestrokeofthetensionbarduringtheseevents,thepresenceofthetensionbar retractionsandimpacts,theexactpointatwhicheachofthetwotensioningcablesbecameslack,andthe finalconfiguration oftheblanketsatthecompletion ofthemastextension.Alltheseparameters relatingto theanomalyweredetermined withinhoursoftheanomalyandwithcompleteconfidence andspecificity suchthatthecriticallyimportantefforttodeterminerepairprocedures tocorrecttheanomalycouldbegin almostimmediately. Considerations forthedeployment ofthesecondsolararraywingwerebeingworkedinparalleltothe investigation ofthefirstwing.Amodification ofthenominaldeployment procedurewasselectedthat includedextendingthemastwiththeTensionMechanisms in"high"tensionmodeandprovidingregular stopstohelpallowsettlingofthepanels.The"high"tensionmodewastoaidinrestraining possible tensionbarmotionsduringpanelstickingwhiletheintentofthefrequentstopswasthatthepanel adhesionmightbereducedwiththeadditionaltimeandpanelheatingthatresult.TheTension Mechanisms wouldberesettothelowtensionmodeforthefinalseveralinchesofmastextensionto minimizepotentialtorquemarginconcernsinthisregion.Thekeyitemthatallowedthismodified procedurewastheevolutionoftheunderstanding ofthemastcapabilityandthedeployment loadsinthe yearssincethetwo-levelTensionMechanism wasdesigned.Analysesandtestssincethenwhichwere re-visitedasaresultoftheanomaly(andtheproposedsolution)showedthatsufficientmaststrengthdid existforhightensiondeployment loadingeveninapartiallyextendedcondition. Threecriticalitemsneedingfurtherinvestigation tosupportthetroubleshooting andrepairprocedure activitieswerethedetermination of(1)whetherbindingofcablesinthetensioning mechanisms was present,(2)whethercablesinternaltotheContainment Boxhadbecomeloose,and(3)iftheretractions andimpactsofthetensionbarhaddamagedsmallspringloadedmechanisms necessaryforproper retractionandstowageofthewingsinthefuture.Alistoftheseandotherspecificareastoinspectand evaluateduringanupcomingEVAwascreated.Theensuinginspectionnotonlyconclusively answered thecriticalquestionsbutalsoshowcased twoincrediblypowerfulcapabilities oftheEVAoperations. Thesecapabilities includedtheabilitytomanuallymanipulate themechanisms (whichallowedthe confirmation oftheconditionoftheinternalmechanisms) andtheuseofacamerainstalledonthehelmet oftheastronautdownlinking inrealtimeandinextremedetailtheconditionofthevariousexternal mechanisms. Figure8providesanexampleofthedetailobtainedbytheEVAinspections usingthe helmetcamandlocalphotography. Althoughoneofthetwohelmetcams hadfailedearlyinSTS-97,the versatilityanddetailofthiscapabilitycannotbeoverstated. Withtheconditionofthefailedhardwareunderstood toarelativelylargedegree,thecreationofrepair procedures proceeded rapidly.Twoofthekeyitemsenablingthequickprogressweretheready availabilityofqualification andfutureflightunitsofthefailedmechanisms for"experimentation" andthe availability ofexperienced designengineersfamiliarwiththemechanisms. Asessentialasthesetwo itemswere,theyarenotuniquetothemannedoperationsofinteresttothispaper.Theyalsowouldhave beendramatically lesseffectivewithoutthethirdkeythatenabledtherapidandthoroughcreationof repairprocedures. Thethirdkeyitemwastherapid"deployment" byNASAofanexperienced multidisciplinary teamtocollocatewiththedesignteamtoworktherepairprocedures. Teammembers arrivedatLockheedMartinfrommultipleorganizations anddestinations withintwentyfourhoursofthe anomalyandincluded: •Astronautswithexperience spanningmultipleEVA'sandfourmonthsontheMIRSpaceStation, •Personnelexperienced inEVAcapabilities, toolsandproceduredevelopment, •Safety&Hazardsrepresentatives, and •P6Trussmechanical systems personnel. NASA/CP--2002-211506 177