Desiqn Chanqes TheinitialTMdesign usedaluminum washers toprovide aredundant rotating surface between the shoulder boltsandthealuminum chassis. Inordertoeliminate thegallingproduced bybearing aluminum washers against analuminum chassis, thealuminum washers wereremoved andreplaced withstainless steelwashers. Inaddition, thenewstainless steelwashers werecoatedwithadryfilmlubeinorderto reducefrictionevenmore. Toreduce theamount ofwearontheTMexithole,theentireTMchassis wascoatedwithateflon impregnated anodic coating. Previously, theTMchassis wascoated withjustanalodine coating which onlyprovided protection fromcorrosion, notwear.Thenewanodiccoating ismuchmorewearresistant andprotects theTMexitholefromthesawing motionofthestainless steeltripwire cable.Furthermore, theimpregnated teflonintheanodiccoating servestolubricate theTMexithole,reducing theamount of wearcaused bythecable.Thecontact between thetripwire cableandtheexitholecouldnotbe eliminated because duetothegeometry ofthesystem, theexitholeactsasapulleyforthetripwire cable. LiketheTMchassis, thehookwasalsocoatedwiththesameteflonanodiccoating, thusreducing friction andincreasing wearresistance. Finally,thekinkedtripwire cableintheSTETMwassimplyreplaced. TestChanqes Theoriginal TMacceptance testdidnotapply"TestAsYouFly"principles. Itsimplymeasured thespring forceintheTMbypullingthetripwire cablestraight outoftheexitholeandthenlettingitretract. Thisis animportant measurement butthisisnothowtheTMisusedduringflight.Duringflight,thetripwire cable ispulledoutofthemechanism withasideloadandthecablerubsonthesurface oftheexithole. Therefore, anewacceptance testwaswrittenthattestedtheTMinthismanner. AspecialsetofSTEwas builtthatallowed theforcerequired toextendthecabletobemeasured versuspayoutradius(RefFig5). AllTMswererequired totestbelowamaximum forcerequirement atambient, cold,andhot temperatures. TheSTETMthatwasusedinthedeployment anomaly failedthistest.Allofthe redesigned flightTMspassed thistesteasily. Through thisinvestigation, itwasalsodiscovered thatthehookslipangle,i.e.,theangleatwhicha tensioned tripwire cableslidesoffofthehook,wascritical. Therefore, asimpleinclinetestwasdesigned tomeasure thisslipangle.Ananalysis ofthedeployment (discussed below) determined thattheslip angleshouldbenogreater than20degrees. TheSTEhookthatwasusedinthedeployment anomaly andthathadthegroove cutinithadaslipangleofover43degrees andfailedthistest.Allofthe redesigned flighthooksmeasured nogreater than12degrees andeasilypassed thistest. Results Priortothesedesign changes, thecriticalclearance between theL-bracket andSARMbracket fora nominal deployment measured 6.0cm(2.4in).Withthenewdesignchanges, thecriticalclearance has beenmorethandoubled to12.7cm(5in). Analysis Thedeployment testsareanimportant method ofverifying workmanship andperformance inthermal vacuum extremes. Asinmostprograms, suchtestingisconstrained bytechnical limits,cost,andtherisk ofdamaging flighthardware. Deployment analysis andsimulation wereusedtocomplement testing and furtherverifytheBoomperformance on-orbit. Ananalysis wasperformed fortheBoomsystem withthe objective ofpredicting hardware clearance on-orbit withareliability of0.999999. Acomputer modeloftheBoomdeployment including theoffloadsystem fortestingwasdeveloped using anin-house, multi-body dynamics solvercalledEzdyn.Themodelrepresents theBoomas2rigidbodies withsprings, dampers, joints,andvarious forcing functions tosimulate friction, deadband, etc.The overhead counterbalance system isrepresented with4rigidbodiestiedwithjointsandcableforces. The modelduplicated thehang-up whenthepayoutradiusofthetripwire cable(RefFig5)waslimitedto34.5 244