correctly.Wesuspectedthecauseofthepittingwasaproblemwiththematerialbecauseofthepoor responsetoheattreatment,butotherfactorscouldhavebeenresponsible suchastheenvironment the canisterwentthroughduringprocessing. Sincewehadagoodcanister,westoppedlookingforthe cause. Thelessonswelearnedfromtheseeventswereasfollows: Carefullyreviewthecertifications on7075T7351afterheattreatmentandmakesuretheconductivity test resultsarecorrect. Insomecasesitmakessensetomakecouponstoverifytheprocesspriortotreatingtheflight components. Thisisinadditiontoin-process couponsthatvalidatehowwelltheprocesswasdone. Couponsshouldbeaprolongation ofthesamematerialafterheattreatingwheneverpossible. Ifpossible,itisbettertohaveonlyonetypeofplatingoperation,suchasallanodizeorallnickelplating. WecouldhaveransometestsearlyontotrytoeliminatethenickelplatingandjustusedTeflonimpregnated anodize.Therewasastrongfeelingatthestartoftheprogramtostickwithourheritage design,butifwehadtakenthetimetoprovethealternatesystemwassatisfactory, itwouldhavesaved overallcostandschedule. Desi.qnin.q forAssembly Thenextproblem weranintoinvolved somedesigndecisions wehadmadeearlyon.Whiledesigning the unitwedetermined thatthelengthoftheSTEMTMthatdeploys themastneeded tobeadjusted tomatch thelengthofthecanister withinatighttolerance range.Thehardware arrangement weusedtoperform thisistheshimsystem showninFigure6.Thisisasimplesystem. However, whenitcametimetoadjust thelength, thereweresomedifficulties. First,itwasnotpractical toperform theshimadjustment onthe benchbyusingdimensions because thetolerance stack-up dimensions weretoolarge.Next,itwas difficult toperform theadjustment horizontally because theSTEMTMdeployer wouldbowwithahorizontal deployment andthrowthemeasurement off.Themethod wefoundourselves usingwastodeploythe mastvertically andadjusttheSTEMTMlengthfromthetopofascaffold. Themastwassetupvertically in ahighbayandwedeployed themastandmarked it.Thenwecutittolength,adjusted it,thentestedand verified thatitworked. Wedidallthiswhileworking 6.7mintheair,reaching downinsidethecanister and boltingandunbolting looseparts.Inonesensethisworked fine;everything cameoutacceptably after spending adaytosetup,andadaytoadjustitandtakeitdown. Thedesignwouldhavebeenbetterifwehadmadethetopadjustment infinitewithjustascrewbolt arrangement sowecouldadjustitbymerelyloosening ortightening abolt.Morebroadly, itmakessense todesignsothatadjustments areeasilymade,orevenbetter,notmadeatall.Shimsareinexpensive on thedesignside,butcostlyontheassembly sideoftheprocess. Shimming islaborintensive andshould beeliminated ifpossible. Another issuethatcameupwasthesystem fordeploying andrestowing thecable.Thecableconsisted of two1.9-cm (3/4-inch) diameter cablesthatwerestowed forlaunchinsidethecanister asshowninFigure 4.Thisprovided acleanpackage, buttestingwasdelayed bythetimerequired toopenupthetopofthe canister andrestowthecableaftereachdeployment test.Apreferred wayofdoingthiswouldhavebeen todesignthecabletobeselfretracting, whichwehadnobudget for,ordesign thesystem forquick removal ofthetipcomponents torestowthecable.Usingengaging features inthepartsandonescrew platetoholdeverything together couldhaveeasilydonethis.Unfortunately, ouroriginal concept of restowing fromthebaseofthecanister didnotworkandwehadtousethealternative method of removing allthescrews eachtimeweneeded toretractthemast.Thisprocedure alsowasperformed 6.7 mintheairasshowninFigure7. NASA/C P--2002-211506 158