TestSetupProblems andSolutions Another issuethatcameupinvolved thecombination launchrestraint/payload tipplate,whichwastobe customer furnished fortheflighthardware. Fortestinghowever, weprovided alaunch restraint/payload tipplate. Themastisrestrained forlaunchbytheCFE-tip platethatisitselfheldonbyaMarman clampbandat thetopoftheoutercanister. Theunderside ofthetipplatehasprovision forrubberpreload cushions that preload themastforlaunch. Tosizethese,wemadesample rubbershimsthatwetestedincompression withabarthathadcutsinittomatchtheclearances between thecanisters. Weperformed thesetestson aSATEC testingmachine, whichgavetheplotsshowninFigure8.Wevariedthewidthandthickness of thesamples toobtainthepreload characteristics wewanted sothecanisters wouldnotrattleduring launch, yethavereserve preload iftherubberdeveloped compression set.Theseperformed properly duringvibration testingwiththemastcoming through withnoevidence ofvibration wear. Having neverusedrubbercushions beforeaspreload devices, itwasthought theywouldbehave ina non-linear fashion. Itwasasurprise todiscover thefairlylinearresponse toloadthatthesamples gave (Figure 8). Lessons FromTestin.q Thetestprogram ranverywellforanewdesign. Thereweretwoproblems, bothofwhichoccurred during coldtesting. Thefirstwasthefailureofthefirstsegment tolatchupproperly shortlyafterdeployment. Thiswascomplicated bythethermal enclosure thatweusedtoperform thetest,whichprevented usfrom seeingthemastasitdeployed, Figure9.Theenclosure wasalargediameter accordion tubesurrounded byinsulation thatwepulledupintoposition around themast.Toachieve coldtemperatures weused liquidNitrogen (LN2)controlled bythermocouples tobringthetemperature down.Aftersoaking forthe required time,webeganthedeployment anditstalledatthepointwherethefirstsegment shouldhave latched intoposition. AtthispointweshutofftheLN2andmonitored themastasthetemperature rosetostudytheproblem. Suddenly, weheardthemastclickintoposition andsawtheoffloading system move.Thisprompted usto seeifthemastwoulddeployfurther, soweturnedonthemotorandthemastranoutallthewaytothe end,witheachsegment operating properly. Themotorhasashutoff switchthatissupposed tostopthe deployment attheend.However, thisdidnotoperate, sowestopped themotormanually. Againwe waitedandmonitored theswitchcontinuity asthetemperature inthechamber rose.Finally, atambient theswitchtriggered, whichindicated apossible thermal problem withtheswitch. Tosolvetheswitchproblem wepulledthedeployer outofthemastandperformed acoldtestonthe STEMTM unitaloneinachamber wherewecouldseeit.Atacoldtemperature, theswitchleverwas clamped hardontheshaftthatsupported it,andthisprevented itfromrotating. Wemodified theswitchby increasing theclearance between theleverandtheshaftandperformed thetestagainandthistimeit operated properly. Wereplaced theunitinthemastandsetupagainforthecoldtest. Thistimeweletthemastdwellforalongertimeperiodatthecoldtemperature andmonitored thetest carefully. Again,themastdeployed andstopped atthefirstsegment latchpoint.Weletthetemperature riseandnotedthattheunitlatched upafteraslighttemperature rise.Wecontinued deployment, still withinthermal specification requirements. Thistime,theswitchoperated properly sowehadapartial Success. Wenextretracted themast,setitupagain,andperformed thehotdeployment, justtoseeifother problems werehidinginoursystem onthehotside.Thankfully, itoperated perfectly. Wewerestillconcerned aboutthecolddeployment, sowemovedtheunitdowntoathermal chamber thatcouldonlydoashortdeployment, butthatwouldallowustowatchitandrepeatthetestquickly. We setupagainandlettheunitdwelllongerandagainitperformed thesame,meaning wedidnothavethe solution. NASA/CP--2002-211506 159