ai-aerospace/ams_data_full_2000-2020 huggingface dataset:
Figure5.Prototypes andfinaldesign oftheC-ring. Diameter oftheringis-9mm. Anin-house developed spindle solenoid (oranelectromagnetic flip-flop)(Figure 6)isusedtooperate a wedge thatcanprohibit contraction ofthelocking ringandthuscontrol disconnection ofthespindle coupling whenseparating pipesfromeachotherandfromthespindle. Whenthewedge islocated between theendsoftheC-ring, itscontraction isprohibited andde-coupling requires veryhighforces. De-coupling mayhappen nominally whenthewedge isremoved frombetween theendsoftheC-ring. Thesolenoid isaflip-flop-type usingapermanent magnet coretomaintain eachofitstwopositions and thusdoesnotrequire anysprings, separate locking mechanisms, orcontinuous powerinput.Powerfeed isrealized withacapacitor thatcanproduce ahighshort-term outputpowerforsolenoid, whilecollecting energyforthenextoperation withalowinputpower. Figure6.Electromagnetic flip-flop andawedge. Adisadvantage withcircular C-rings wasalsofound.Priortocoupling, theC-ringisinafreestateandcan rotatefreelyduringcoupling. Theringmayrotatesothatitslightlytouches thinendthesecuring wedge. Afterthecoupling isperformed, however, theringisinslightlystressed statetoprovide somepreload for thecoupling. Inthestressed statetheringcancauseextrafriction, whichprevents moving ofthesecuring wedge andthusprevents securing actionorrelease ofthelock.Acoupleofdesigns weretestedto reducemovement ofthering.First,asingleaxialspringwirewasmounted ontheringopposite thesplitto givesomeguidance. Latertheendsoftheringwereshaped sothattwostationary pinswoulddefinethe position oftheunstressed ring.Thisenhanced actionoftheringslightly. Alargerringwouldallowlarger tolerances andwouldmakeuseofthemoving wedgeeasier. Itwasalsonoted,thatthehardened steel ringhasatendency todigintosoftersteel,whichmakesseparation forceunrepeatable. Further external torqueorbending hassomeeffectonrelease forces, whichmaybeduetonon-symmetric modified rings orminorgeometrical errorsinring-groove geometry. Altogether thesystem seemstobeverysensitive to theaccuracy ofthegeometry. Asimplein-house developed slip-ring assembly (Figure 7)isusedtotransfer electricity totherotating spindle forthespindle solenoid andactivedrilltoolfunctions. Therearefiveisolated linesintheslipring. Forprototyping purposes theringsaremadeofbrassandbrushes aremadeofspringsteel.Oneringhas asplittobeusedforabsolute spindle position detection. 191
Figure7.Slip-ringassembly. Thespindle, manufactured mainlyfromsteel,ismounted onasledge(manufactured ofaluminum) that movesupanddownalongalinearslide.Foreffective useofvolume, thedrillingmotorislocated aside thespindle andbelowthesledgeandthemotionistransmitted withageartrain.Absolute spindle position isdetected withtheaidofasplitintheslipring.Thesplitintheringisdetected asabreakinelectrical current. Afterthis,signalspindle position iscalculated fromincremental encoder mounted totheendof thespindle motor. Wiretenslonct Feedlllt_[()i Bailscrewinpulgear Sledge onslides Spindle molar Spindle Lim:ar shdes Pipecarousel lowerbeanng Central strut Toolcarousel Figure8.Linearfeedsystem. LinearFeed: Linearfeed,moving thesledgeandspindle upanddown,isrealized withathinballscrew,rotatedwithan electric motor,andaballnutthatismounted onthespindle sledge. Thesledgeisguided byfourball splines thatrunalongfourguiderods.Drillingforce+100Nismeasured withaloadcellattached tothe leadscrew. Theloadcellcanmeasure onlycompressive forceandtherefore theleadscrewis pretensioned to100N.Axialloadonthescrewiscarried bytwothrustbearings andradialloadiscarried withtwoneedlerollers(Figure 8). 192
I.o_crbearing Figure 9.Pipecarousel andtoolcarousel. Stringholding device: Astringholding device, located between toolcarousel andlowerendoflinearslidesystem, isusedto holdthelowerpipeinplaceduringpipeconnection ordisconnection. Clamping ofthepipeisdoneatboth sidesofthestringwithtwopaws,shown inFigure 10,arecoated withsoftrubber-like high-friction material toaccommodate helicalfluteofthedrillpipes.Thepawsareattached tolinearslidesandthe linearmovement andclamping forceareprovided withtwoindependent cammechanisms located onboth sidesofthestring.Geometry ofthecamissuchthattheclamping forceapproaches infinityasthetravel approaches itsmaximum. Thetwoclamping motors aredriveninanelectronically synchronized wayto guarantee thatthepawswillclampthestringwithequalforcesandinthemiddleofdrillingaxis.Position ofeachslideismeasured withalinearpotentiometer. Figure 10.Stringholding mechanism. Forcoupling andde-coupling ofthepipes,thestringholding devicemustprovide aIO0-Nlinearholding force,which,withafrictioncoefficient of0.25,needsaclamping forceof400N.Thearmoftheclamping 194
forcewillremainaminimum0.5mm,whichgivestheneededtorqueinthecamaxleof0.2N.m,Witha MaxonREd13118430motorandMaxon110316gear(max.torque0.3N°m),a400-Nclampingforceis reachedwitha0.75-mmforcearm,orwith0.5-arm, a600-Nclamping forceisachieved. Tools Inthebeginning oftheprojectitwasconsidered whether tousehammering actiontochipthematerial or not.Fromamechanical pointofview,itwasconsidered whether todevelop ahammering system onthe drill-eventwometers and10couplings abovethedrillbit,ortofitaminiature hammering deviceinsidea drillpipe.Fromanelectrical pointofview,thepowerneedforsuchahammering devicewasconsidered. Fromascientific pointofview,itwasconsidered whether theinteresting remains ofpossible fossilswould befoundfromsediment layersofsandstone andlimestone-like materials, ordowereallyneedtodrillinto hardrocklikegranite. Aftertheseconsiderations, itwasdecided toproduce thisfirstprototype without hammering actionandrelyoncuttingandgrinding basedremoval ofmaterial. Forthispurpose, veryhard andsharpdiamond-like drillbitswouldsuitthebest.Ifforscientific reasons carbon-based materials can notbeused,boron-nitride hard-alloy wouldprovide agoodreplacement. Forthisprototype thetoolbits aremadeofindustrial hard-alloy Sandvik DZ05havingHV30hardness onVickers scale. Thetoolusedforsampling duplicates asadrillingbitandacoredrill,asshowninFigure11.Thetoolis designed todrilla17-ram-diameter holeintorockmaterial andtocontain a9-ramdiameter and20-ramlongcoreinsideit.Acrownthatcarriesoutthecuttingisconstructed ofsixcuttingbitsmadeofhardalloy. Duringdrillingacoredevelops insidethedrillwhilethebitcrownchipsmaterial. Chipsareconveyed to thesurface bytheexternal helicalprofile.Oncethecoringsection isfull,theheadcutterchipsthecore top.Theeffectisthatthebitpenetrates deeper intothematerial always holding a20-ram coreofthe current depth.Whenthedesired depthhasbeenreached, thecoreisbrokenapartfromthebasematerial withtheaidofawedge-shaped corelifterbyliftingandturningthedrill.Thisactionissimilartothatused withconventional rock-core drills.Forsampling ofsandorothersimilarloosesoil,specially designed flaps willbemounted nexttothecoreliftertoholdsample insidethetoolduringlifting.Atotalofninetoolsare storedinthetoolcarousel andtheyareintended topenetrate intorocksofhardness similartolimestone andsandstone. Inthisconfiguration, theDSSwillcarryindividual toolsforeachsample tobeacquired duringasingletripbetween thelanderandthesampling location. Afreshtoolwillbeattached tothedrill stringbeforeeachsample acquisition, andthensubsequently detached withthesample inside. _/I¸,_ J Figure11.Tooldesign andprototypes (missing drillbitshere). Preliminary testswithdifferent typesofcuttingtoolswerecarried outinearlystageofproject. Thetests showcuttingpowerthatwouldcollectarockcore10mmindiameter and15mminheightwithinafew hours.Quicktestsonveryhardandabrasive Finnish granite indicate thatwithgiventhrustandpowerit wouldbepossible tocollectsimilarrockcoreinatimeframeoftensofhours,however, durability and selection ofdrillbitmaterial willbeacriticalissue.Thetoolsthatweretestedwere(Figure 12): 195
Drillinqtests Witharotarycoredrill,30-Nthrust,30RPM,without hammering action,corediameter -10mmanddepth -15mm,usinghard-alloy cuttingtoolbits,ittakesafewhourstotakeasample fromasoftrocklike marble orlimestone.Forhardrocklikegranite ittakesatimeframeoftensofhours,butdurability and selection ofdrillbitmaterial wouldbeacriticalissue.Forhardrocksrotation speedhasagreateffect,the fasterthebetter. General 3Dvolumetric development together withrapidprototype modeling techniques isaveryefficient andfast waytodesigncomplex systems withmoving parts. Prototyping andtestingofmechanical subsystems already duringdesignphaseisveryimportant. Nothing shouldbelefttobeinvented withthefinalhardware. Payattention fordesignofwireharness, especially ifitismoving. Conclusions Theworkpresented hereproduced thefirstprototype ofasmallmobileroboticdrillingdevicecapable to extendandretractanextendable drillstringreaching uptotwometers intosoil.Scaling thedevicesmaller alighterandsmaller drillcanbedeveloped, orifdesired todrilldeeper, abiggerscaledrillwithsimilar actions couldbeconstructed. Withthissize,andespecially withscaled-down devices, volume available fordrillmotors setscertain limitsforapplicable drilling powerandspeed. Thelessons learned section indicates someofthedevelopment targets thatshould beconsidered forthenextgeneration ofthe prototype. References 1.'Exobiology intheSolarSystem andTheSearchforLifeonMars'ESASP-1231, ISBN92-9092-520-5 2.'Nanokhod Microrover Heading Towards Mars'Fifthinternational Symposium onArtificial Intelligence andAutomation inSpace, I-Sairas '99,ESASP-440 August 1999 3.'ARobotic DeepDrillerforMarsExploration' J.Suomela, Helsinki University ofTechnology, Helsinki, Finland; G.Visentin European Space Agency, Noordwijk, TheNetherlands; T.Ylikorpi, Finnish Technical Research Center, Helsinki, Finland; MZelikman SpaceSystems Finland, Helsinki, Finland; Invitedsession on"Mechatronic Applications inAerospace", IFAC-2000 198
Freein+Y _ /--FreeinY-ZPlane -,_ _rner D(#4)CornerC(#2) Capture Bar C°arse Alignment C°ne e_ z£_x FineAlignment Receptaci FixedinY-ZPlane "_:_k, _" FreeinY-ZPlane CornerB(#1) __ CornerA(#3) Note:inaddition tothein-plane freedoms identified, allfour cornershavelimitedswivel freedom (Oy,O_) Figure 5.P6LongSpacer Truss Attachment Features FineAlignment Shear Cylinder Torque Reaction Pros bi .tlt -JII,Contingency Spacer ZIZenith BulkheadLocking Device I ., _ --_Contingency BoltSpacer --Primary Attachment Bolt Note: Sho'._11 withlaunch restraint capremoved priortoberthing Figure 6.ZlFineAlignment/Bolt Installation(.;round Strap, Stoveed Position__LongSpacer Comer Fitting j .  -_ Contingency Bal[Nut -_. _ _,- Threaded Sleeve -_Primary Ball Torque Reaction Slots Figure 7.P6FineAlignment/Nut Installation 2O9
i P6LongSpacer __Z1Truss Contingency NutLocking Plate-_ iS RaceFloat Ground Strap"_\\ / / Locking Plate _\\ / / Contingency BalVNut _ "_ // Sleeve Retention PIPpin_ _ _-=_/ j -- // Threaded Sleeve _..\ ____ .__:?:._. // \ / \\\ / . // / / 1" / / // / / y"_ FineAlignmem ShearPrimary. Race// / Centering Spring / Cylinder / Primary Attachment Bolt LongSpacer _ / Comer Fitting / Primary BallContingency SpacerLocking Device Contingency BoltSpacer / /__('ontingency Attachment Bolt Self-Feeding Nut Microconical Torque /---Reaction Fitting / / .-?. \ li t:_?k iFigure 8.P6-Z1Mated Configuration I_ZlCAPTURE LATCH I i'" 275  fl 5l'43' -_ ,080 / I_R6CAPTURE BAR Figure 9.Capture LatchAssembly Figure 10.Capture Latch-Capture BarOffset 210
Note: Ground Strap NotShown ForClarity Ground SIrapStoppage Bolt-- Contingency NulLocking Plate 4Contingency BalUNul Threaded Slec',c ,_, Primal* Ball--Sleeve Retention PIPpin t44'y::--.PIPPinSlec',c Figure11.ZICongingency Spacer LockTool i: _:i:iii_iil¸¸¸i¸i¸ Figure13.P6Primary Race withCentering SpringsFigure12.P6FineAlignment/Nut Installation RearView Figure14.P6Contingency Race withCentering Springs i.... l__ I_ I,:,Fr__ET Figure15.ZlShearCylinder Entering P6Ball/Nut, atReadytoBoltConfigurationFigure16.Z1FineAlignment/Bolt Assembly 211
1.Freedeployment system,noratedampers. a.Advantages: Lowestcostandmass,simpletodesignandfabricate. b.Disadvantages: Controlchallenge,highvelocitydeployment, motionpathcontrolnot withinacceptable limits,noheritageorinformation availablewithothermissionsor organizations, verylargeIockuploads. 2.Singlemotordrivensystemwithsynchronized panel-to-panel deployment. a.Advantages: Robust,largemotortorquemarginsavailable,momentum controlusing motor,predictable motionpath,arrayretractioninflightpossible(notarequirement), similarflightsystemsinuse. b.Disadvantages: Highestmassandcost,multiplepartsandfailurepoints,longleadtime forengineering modelmotor,motordriveandcontrolelectronics arehigh$andmass costfora"onetime"event. 3.Springdrivensystemwithsynchronized paneltopaneldeployment usingeddycurrentdampers formomentum dampening. a.Advantages: Lowercost,similarmassto"2"above,singledamperattheyokecontrols systemmomentum, eddycurrentdamperrequiresnopower. b.Disadvantages: Mechanically complex,manysinglepointfailurepoints,norecentflight historyfoundonavailableeddycurrentdampers,highmassandsizefordamper,system massveryhigh,smalladjustment rangeofdamper. 4.Freedeployment systemwith"saloondoor"hingesandovertraveldampers. a.Advantages: lowcostandmass,longAPLhistorywiththisstyleofhinge,minimal complexity, andminimalpowertooperate. b.Disadvantages: Controlchallenge,highpaneldeployment velocity,challenging tolock panelsinplace,totallyunpredictable motionpathcontrol. 5.Freedeployment withviscousdampervelocitycontrol(PDRBaseline). a.Advantages: communication satelliteheritage,acceptable massandcost,good momentum control,acceptable motionpathvariability,dampershavewiderangeof adjustment. b.Disadvantages: Temperature controlofdampersrequired,additionaldampertest, qualification andcharacterization programrequired. 6."Offtheshelf'purchasefromanoutsidevendor. a.Advantages: Shiftsubstantialriskandheadaches tothevendor. b.Disadvantages: No"offtheshelf'design realistically available, modification toexisting designs required, substantial investment oftimetomonitor contract andtechnical issues withtravelinvolved ofkeypersonnel atofteninopportune times(personnel availability). Weevaluated eachoptionindetailandchoseoption"5",thefreedeployment system usingviscous dampers ateachhingeline. Therelatively simpledesigncoupled withacceptable massandcostweighed heavily. Theteamrecognized earlyonthatwiththemanpower andschedule constraints present, makeorbuy decisions forindividual mechanisms leanedheavily toward thebuyside.Asaresult,thedecision was madetoinvestigate andbuycommercially-available damper andrelease mechanisms andadaptheritage hinge,ball&socket, andbearing designs tothepurchased items.Brieflysummarized herearetheresults ofthetradestudies: 1.Choice ofeddycurrent vsviscous fluiddamper. a.Viscous dampers haveflightheritage atAPLandGSFC. b.Largerangeofadjustment available forviscous damper. c.Airbubbleconcerns withviscous damper. d.Concern withhigh-speed gearing ineddycurrent damper. 215
TheDEBManufacturing Model1025viscousrotarydamperwaschosenwithseveralmodifications suggestedbyDEBandGSFCinfillandtestingprocedures tominimize concern overthedevelopment of anairbubbleinthefluidduringvacuum operation. 2.Choice ofrelease mechanism. a.Pinpuller:Extensive heritage atAPL,highshock, hardtoadapttothisconfiguration, relatively highmass. b.Release nut:Lowmass,lowshock,easilyadaptable toseparation boltconfiguration. c.Thermal knife:Highpowerincomparison withotheroptions, concern aboutsimultaneous deployment ofeachpair. d.Cablecutter:Extensive heritage atAPL,highshock,cablewouldreplace separation bolt, wouldneedloadcellinplaceofstraingageinthebolt. TheHi-Shear 9321lowshockseriesseparation nutwaschosen combined withastrain-gaged BeCubolt astherelease system foreachwing. Design Timeline andConcept Evolution Themajorfeatures ofthearraydeployment system gradually matured astheprogram progressed. Summarized belowisthedesign asitstoodatselected program milestones. Sincemuchofthe spacecraft design hadbeencompleted, moretimecouldbespentonthearraydesign, enabling agood dealofprogress tobemadeinoneyear. SolarArrayBaseline Desi.qnatSpacecraft PDR,February 19,1997 •Four(123cmx132cmx1.59cmthick)panelsperwing. •Aluminum corepanels withGrCEfacesheets toeliminate 'thermal twang' ofthepanels during transitions inandoutofeclipse. •Twotorsion springhingeswithviscous dampers perinter-panel hingeline. •Torsion springactuated yokealsowithviscous damper. •4ball&socketsupports perwingtotakeshearduringlaunch. •2pyropinpullerswithlongboltswithloadwashers thatcontrolpanelpreload andrelease eachwing. •Pinpullerslocated onspacecraft sidetominimize pyroshocktosolarcells. •Heated dampers (8Wmax)tocontroldamper temperature. •Panelslockattheendofdeployment. •Cellsonoutside panelfaceoutward duringlaunch. •Solararraydeployment actuator (SADA): Schaeffer Magnetics Type3actuator motor. Duetomanpower constraints, thesolararraybaseline designwasveryimmature atthespacecraft PDR. AfterPDR,theupdated fourpanel/wing Pro-Engineer layoutwascompleted, allowing theNASTRAN structural analysis ofthewinginboththestowed anddeployed conditions toproceed. Bytheendof March, 1997,completion oftheinitialkinematic deployment analysis using2DWorking Modelv4.0 provided theflightbaseline springanddamping coefficients, uncovered lock-up loads,facilitated damper procurement, andpermitted theflighthingedesigntostart.Astheflightmechanism designs matured, a separate solararrayengineering designreview(EDR)washeldinJuly1997toreviewtheprogress made tothatdate.GSFC mechanism experts served onthereview boardandsuggested changes that significantly improved theJHU/APL wingdesign. First-cut deployment testplansandverypreliminary ground support equipment designs tosupport thewingdeployment testing alsowerereviewed. Solar arraydesignchanges fromthespacecraft PDRaresummarized below: SolarArrayDesi,qn atSub-System E.DR,July1997 •On-orbit SADArotation setat0°-100°. •20odroopanglechosen tominimize solarpressure torques (forPDRitwas30°). •Low-shock separation nutssubstituted forheritage pinpullers, nutsmounted onbackside of outermost wingpanelforaccessibility. 216
•Instrumented (strain-gauged) releaseboltchosenoverloadcelldesigntosavemass. •Constantforceleafspringreplacedtorsionspringatyokehingetosolvepackagingproblemsand savemass. •Cellsmovedtooppositesidesofpanelstoreducetheangleofrotationintothesunrequiredduring initialdeployment andtoprotectcellsfromdamageduringintegration. •4Supportpoints(2release,2ball&socket)substituted for6points(atPDR)basedonNASTRAN stowedfrequencyanalysis. SolarArrayDesign atSpacecraft CDR,December, 1997 Thesolararraydesignwasessentially complete atthespacecraft criticaldesignreview(CDR), heldin December 1997.Solararraydesignchanges fromthesolararrayEDRaresummarized below: •Four(199.6cmx125.2cmx1.3cmthick)panelsperwing(11.1m2totalarrayarea). •Aluminum facesheetsreplaced GrCEfacings. Thermal twangofaluminum faceswasevaluated and deemed acceptable undertheTIMED jitterrequirements. Useofaluminum facesallowed useof magnesium inserts, representing alargemasssavings overthetitanium inserts required for coefficient ofthermal expansion (CTE)compatibility withGrCEfacings. •Twoself-aligning spherical bearings ateachinter-panel hingelinereplaced thetwoEnvexbushings. •Onespring/damper assembly perinter-panel hingelineinstead oftwotosavemass. •Hi-Shear 9321low-shock separation nutchosen. •Retraction springonrelease boltaddedtoincrease clearance between boltandpanelbasedon detailed kinematic analysis. •Fourpointwinginterface tothespacecraft modified totwoflatsattherelease bolts,oneballand socket, and1'V'groovetoaccommodate thedifference intemperatures between thespacecraft body andthewingassembly aftertheapproximately twohourtimespanbetween launch andwing deployment. •Modified damper coverfromaluminum tomagnesium tosaveweight. Concern wasexpressed attheCDRconcerning thenumber ofeclipse cycles, thelargesizeofthecells, andtheCTEmismatch between GaAscellsandaluminum facesheets. Inaddition, in-depth conversation withthelaunch vehicle manufacturer indicated that53kgadditional spacecraft launch masswas available bymaking various minorchanges tothelaunch profile. Itwasdecided toinitiate another structural iteration onthesubstrates, usingGrCEclothfacesheetswithdownsized titanium inserts. This wasaccomplished withdrawing release inFebruary 1998. Summary ofSolarArraySystem Milestone Dates: ;_Conceptual Design Review (CoDR): December, 1994;Spacecraft designactivities halted. Preliminary Design Review (PDR):February 19,1997. SolarArrayEngineering Design Review (EDR):July19,1997. ;_Critical Design Review (CDR): December 3,1997. ;*Substrate Contract Fabrication Start/Finish: 2/98to7/30/98 _,CellVendor LaydownContract Start/Finish: 8/98to9/20/99 ;_APLMechanical Assembly Start:9/30/99. ;_SCEnvironmental TestStart:10/18/99. FlightDesign Configuration Figure1illustrates theTIMED spacecraft intheorbitalconfiguration. Figure2showsasolararraywingin thelaunchconfiguration. 217
IpCAtBEWCH I_DIT[LESCOP[_ ;4) STAR CAWERAS (2_ G_SAW1EWWAS _2_  _$E( INSTRUMENT I ANI(_NA t21 Figure1 Panels/Substrates Each1.31-cm thickpanelconsists ofNippon SF-50A-75/Bryte EX1515 GrCEspread fabricfacesheets on1.3-cmthick,3/16-5056-.001P aluminum honeycomb core.\Facesheetsconsist ofthreepliesangled as(0,45,0) andarebonded tothealuminum coreusingBryteEX1516 filmadhesive. A0.0076-cm thick Kapton TypeVNfilmisco-cured withthetopsidefacesheettoserveasanelectrical insulator forthe solarcells.Insertsforhighlystressed areasare6AI-4V machined titanium. Lightlyloaded fasteners use AEPandRosanfloating nutinsertspottedwithFiberResinSLE-3009 adhesive. Figure2 Yok_.._._e Figure3shows theyoke,whichprovides theinterface between theSADAandthepanelassembly. Machined almost entirely ofZK60A-T5 magnesium, eachyokehasamassof4.0kginfullflight configuration 218
Figure3 Energy forthe70°deployment oftheyokeattacharmisprovided bya2-plyberyllium copper (BeCu) constant-force leafspringthatprovides drivetorquethatis>5.0timesthemeasured frictiontorque. The armrotates byvirtueoffourKaydon preloaded angular contact bearings lubricated withBraycote 601 grease. TwoDEBviscous rotarydampers provide velocity control fortheyokedeployment arm.Two adjustable stopsprecisely locatethearrayattheend-of-travel (EOT),withalimitswitchtosenseproper deployment. Having nolatchattheyokeenables eachwingtofoldduringre-entry, providing theproper burnup/debris scenario. SADA TheSADAprovides the110°ofrotation required bythewingduringorbitaloperations. Itisastandard MOOG/Schaeffer TypeIIIharmonic driveactuator. Arotarypotentiometer provides 180°ofposition data. Atypicalrotation angular velocity forthisactuator willbe~l°/sec. ATypeIIIactuator provides thedesired shaft/bearing stiffness forthedeployed arraywing.Thetorquemargin onthemotoriscalculated tobe muchgreater than5.0. Hinqes Panelhingelinesconsist oftwostainless steel,self-aligning spherical bearings, oneofwhichisjoinedto asinglespring/damper assembly. Eachbearing islubricated withBraycote 601grease. Thehinge,shafts andbearing housings aremadeofZK60A-T5 magnesium hardcoated withaproprietary 'Mag-oxide' coating provided byLukeEngineering. ThesingleDEBviscous damper ismounted tothemainshaft through aflexible coupling andprovides velocity controlovertheentire180°oftravel.Ateachspherical bearing housing, asmallleafspringridesupandoverawedgeandprovides asolidIockupofeachpanel hingelineattheEOT.Eachhingelineofawinghasacustom Elgiloy helicaltorsion springwhose variable preload issetbasedontheresults ofkinematic analysis andground test.Thespringprovides drivetorquethatis>5.0timesthemeasured frictiontorque. Viscous Dampers TheDEBManufacturing Model1025viscous rotarydamper waschosen toprovide deployment rate control foreachwing.Building onGoddard Spaceflight Center (GSFC) experience withthisdamper, extensive testingwasperformed tocharacterize typicaldamper performance undervarious temperature andloadconditions. Thedamper usesarotating vanetoforceCV-7300 silicone fluidofchosen viscosity through anadjustable orifice,providing upto1411N-cmoftorqueinapackage weighing -0.5kg. Forthismodeldamper, thedamping coefficient wasfoundtovarynonlinearly withneedlevalvesetting, temperature, direction ofrotation, andsurprisingly, withapplied torque. Thelattercharacteristic influences thetesting sequence forsetting upandtesting theflightwings.Toaccurately predict thebehavior ofa particular damper undertemperature andvarious needlevalvesettings, thenettorquethateachdamper seesmustbeaccurately measured. Therefore, thespringtorque anddragtorques frompinfriction, 219