rotaryjoint.Thesedesignchangesweremadebyredliningtheoriginaldrawingsthatwereusedto fabricateanengineering unit.Minordesigncorrections werecapturedontheseredlines,whichwerethen releasedforprocurement oftheflighthardware.Thisapproachstreamlined thedesigneffort considerably. NASAbenefitedfromacontractrequiringadeliverable engineering unitandspares.Theoriginal HoneywellSSOfJPLcontractfortheSeaWindsSAScalledforconstruction oftheengineering unitSAS,a flightunitSAS,andflightsparesubassemblies forcontingency. Theseincluded aspareSAA,BSA,EA, AAandrotaryjointassembly. WhentheADEOS Ispacecraft, carrying theNASAScatterometer (NSCAT), waslostinJuneof1997,NASAdirected JPLtoinitiatetheQuikScat mission toquickly reinitiate thescatterometer datastream. JPLdirected Honeywell SSOtointegrate thesparesintoa second flightSASunit.ThespareSASalongwithspareCDSandSESunitswerethenintegrated together ontotheQuikScat spacecraft withtheintentoflaunching thespareinstrument asquicklyas possible tofillthedatagapleftbytheNSCAT loss. Thedifferences inthedynamic launchenvironments ofthetwoSeaWinds missions wereconsidered. ThespinaxisoftheSASasmounted totheQuikScat spacecraft buswasinlinewiththeflightdirection of thelaunchvehicle, whereas thespinaxisoftheADEOS IImounting wasperpendicular totheflight direction duringlaunch. Thus,thedirection ofquasi-static loading duetoacceleration duringlaunchwas different forthetwomissions. ATitanIIlaunchvehiclewasselected fortheQuikScat mission. The ADEOS IIspacecraft isscheduled forlaunchonanHII-A.TheTitan11launchvehiclegenerally haslower acoustic andrandom vibration launchloads(nosolidrocketpropellant) thantheH-IIA.Fromanalysis it wasdetermined thatnostructural designchanges wererequired duetothesedifferences indynamic environments duringlaunch. Thethermal environment oftheQuikScat mission wasdetermined tobemoreseverethanthatofADEOS IIfortwomainreasons. First,eventhoughboththeQuikScat andSeaWinds onADEOS IImissions utilize800-km, sun-synchronous orbits,therelative spacecraft orientation withrespect tothesunis significantly different (Betaangle). TheresultisthatinthecaseofQuikScat theSAS-Ysurfaces are continually sunpointed andthe+Ysurfaces alwaysviewdeepspace,averydifferent attitude thanthat whichwillbeseenbySeaWinds onADEOS II.Secondly, QuikScat isadedicated mission housing only theSeaWincls instrument. ThustheSASismounted aloneonthenadirdeck,whereas intheADEOS II configuration SeaWinds issurrounded byseveral otherinstruments, whichbothprovide thermal shielding aswellasradiateheattoit.Thisnecessitated several thermal controldesignchanges including radiator surface areareduction andlocation change, thermal blanket modifications, andtheaddition ofexternal "survival heaters". Thedesignofthesurvival heaters involved bonding RER65 resistors totheoutside of theBSAwithathermally conductive epoxyintheproximity oftheduplexbearings. Theheaterresistors werethenwiredinplacetoformtwochannels ofseries-parallel heatercircuits. Lessons Learned Itwaslearned duringthke GGSprogram thatamoreSecuremethod ofretaining theseparation nutwas needed. Theuseofsafetywiretoprevent ejection ofthec-clipwascumbersome, timeconsuming, anda "band-aid" solution atbest.Asdiscussed intheprevious section, amuchbettersolution wasto incorporate athreaded noseintotheseparation nutdesign_ ...... Another lessonlearned camefromunexpected embrittlement oftitanium. Duringtensioning ofthe V-Band ofthesecond flightunit(QuikScat) the(6At-6V-2Sn) titanium strapoftheV-Band suddenly fractured. Although nootherdamage wascaused, thefailurecameasquiteasurprise considering the maturity ofthedesign. Thefracture occurred atthethin,webbed portionofthestrapatalocation near therighttrunnion. Analysis showed thatthestressatthefracture wasabout196MPa(28,400 psi),far belowthe1000MPa(145,000 psi)yieldstrength ofthematerial. Nofailures occurred ineitherthefirst 282