trussthermalpropertieswereevaluatedintheanalyses.Oncetemperatures weredetermined fromthe thermalmodels,theyweremappedontothecorresponding elementsofthestructuralfiniteelement models.Finiteelementanalysiswasthenperformedtodeterminestructuraldeflections. Throughfurther processing, therelativedeflections ofcorresponding P6toZ1attachpointswerecalculated.Todetermine thedeflections inarelativesense,thefixedcornerwastheoriginofacoordinate system thatwas positioned angularly by+/-Yslidingcorner4. Attachment Restraint Figure5indicates thedegrees offreedom inthefinealignment assembly's primary nutslocated ateach corneroftheP6.Figure8showsacrosssection ofafinealignment mechanism withtheZ1primary EVA boltengaged intotheP6longspacer primary nut.Spherical bearings areusedaround boththeprimary andcontingency nutstoprovide alimitedrotational freedom abouttheYandZaxes.Thisbearing arrangement provides reliefforon-orbit differential thermal expansion anddistortion thatmayoccur between theZ1andP6duringon-orbit operations. Thearrangement alsoaccommodates angular misalignments duetomanufacturing tolerances. Inaddition totherotational degree offreedom intheprimary nutassemblies, thereareprovisions for slidingintheY-Zplanetoallowfordifferential thermal expansion oftheP6andZ1.OnecorneroftheP6 incorporates afinealignment nutassembly thatisfixedfromslidingintheY-Zplane.Asecond corner incorporates anutassembly thatisallowed toslideintheY-direction only.Thetworemaining corners incorporate nutassemblies thatareallowed toslideintheY-Zplane.Thisarrangement allowstheboltsto reactshearandtorsional loads,whilestillallowing thestructures toexpand andcontract thermally. Theslidingdegrees offreedom intheP6nutsideofthefinealignment mechanism isaccomplished by incorporating agapbetween thebearing raceandthetrusscornerfitting.Themagnitude ofthesegapsis established baseduponbothparttolerances andpredicted thermal displacements. Allofthecontingency nutsintheP6finealignment deviceareallowed toslideintheY-Zplane.Theshearcylinder attheprimary boltlocations stillcarryshearloadsevenwhenthecontingency boltisinstalled. Afterthestructural connection ismade,loadsaretransmitted acrosstheZ1-P6interface asfollows: +/-Zin-plane shearload-reacted byfixedtrussjoint&trussjointthatisfreetoslideinthe+/-Ydirection +/-Yin-plane shearload-reacted byfixedtrussjointonly +/-Xaxialload-reacted byallfourtrussjointcorners Race-Nut Centerinq TheP6primary racescontain springs thatkeeptheball/nut elements centered forentryoftheZ1fine alignment shearcylinder (seeFigure13).TheP6ballopening, Z1shearcylinder tip,andtheP6centering springgeometries ensure finealignment feature engagement whenlateralmisalignments arepresent, as limitedbycoarse alignment feature clearances. Suchmisalignments maybeduetothermal gradients and manufacturing tolerances. TheP6contingency racescontain springs thatkeeptheball/nut elements centered forZ1contingency spacerseating (seeFigure14). BoltInstallation Torque Reaction Primary boltinstallation torqueisreacted bytwopinsintheZ1shearcylinder engaging matching slotsin theP6primary balls.Thesefeatures keeptheP6nutfromturning duringinstallation oftheZ1bolts.In addition, thenutisfreetoslideandrotateafterfulltorqueisapplied. Thetorquereaction features were designed toengage withtheP6primary ball/nut rotated toitslimits,translated toitslimits,andwiththe maximum gappredicted fromthethermal andmanufacturing tolerance studies. Figure15showsalayout oftheZ1shearcylinder entering theP6ball/nut withtheZ1torquereaction pincapable ofresisting torque against theP6balrsslot.Thelayoutshowstheshearcylinder axiallyseparated fromtheP6balla distance equaltothemaximum expected gappredicted fromthethermal andmanufacturing tolerance studies. TheshapeoftheslotintheP6ballandthepositioning ofthepinintheZ1shearcylinder were critical,havingbeenderived fromaseriesoflayouts reflecting theexpected relative misalignments. Those layoutsensured thattheZ1pinwouldentertheP6primary ballevenwiththeballrotatedtoitslimit. 2O2