ai-aerospace/ams_data_full_2000-2020 huggingface dataset:
gearhead. Sealfrictionontheshaftfurtherreducedspeedtoapproximately 150to200rpm,whichis adequatetogentlystirthemixture.Themotorisquitesmall(8mmdiameterX31mmtall)andevenwith a64:1gearheadhaslimitedtorque.Thebiggestchallengewastocoupleandsealtheshaftwithout introducing excessivefrictionorsideloads.Toaccomplish this,themotoroutputshaftwassomewhat looselypinnedtotheimpellershafttoallowsomeangularmisalignment andflexibility.Theshaftwas sealedattwolocationswithlightsqueezeo-ringslubricatedwithasmallamount ofhigh-vacuum perflouropolyether (PFPE)-based lubricant. Despite earlyskepticism, thecoreless d.c.motorperformed wellinvacuum. Durin_qualification testing, themotorwasoperated for16hourscontinuously inavacuum ofbetterthan1X10Torr.Theuseof vacuum-compatible lubrication wasthought tobeimperative forthissuccess. Putting ItAllTogether Eachofthebasicfunctions (soildelivery, waterstorage anddelivery, reagent delivery andstirring) requires several components tocomplete itstaskandmonitor theresults. Thecomplete listof components isasfollows: WaterTank TankSealPuncture Actuator 9 TankSealPuncture Needle TankSwitch TankHeaters TankRTD Drawer Drawer actuator Drawer limitswitchDrawer extension telemetry switch Drawer retraction telemetry switch Drawer heater Drawer RTD Reagent dispenser Stirring mechanism Pressure sensor Electrical connector | I Figure7-MECAWetChemistry LabMechanisms withWaterTankRemoved Oneofthemoredifficult challenges oftheprogram wastopackage allofthesecomponents intothe7.0X 7.5X8.0cmspaceavailable abovethebeaker. Themassofthecombined system (excluding the beaker) waslimitedto365grams. Thedesignprocess required concurrent engineering ofseveral components. AsingleCADdesigner wasfedinformation fromseveral engineers. Asolidmodelwas created inIDEASandmaintained throughout thedesignprocess. Packaging trade-offs were continuously discussed, refinedandincorporated intothesolidmodel. Thisprocess worked wellandis considered oneofthesuccesses oftheprogram. Asinglemodelcreated byacentraldesigner provedto workquitewellforthisprogram. Adedicated, highlyskilleddesigner wascriticaltothisapproach. 37
Despitetheuseofsophisticated software,thesolidmodelshouldstillbethoroughlyreviewedforpart interference. Severalinstancesofpartinterference wereencountered inthisprogram.These discrepancies wouldhavebeenverydifficulttocatchinhardcopydrawingreviews.Athoroughreviewof theCADsolidmodel,however,mayhavecaughtmanyoftheseerrors. Anotherlessonlearnedforthistypeofmechanism istoleaveadequateroominthedesignforelectrical connections andwirerouting.Thisprovedtobeadifficulttaskthatwouldhavebeeneasierifmoretime hadbeenspentconsidering alternatives earlyinthedesignprocess. Conclusions Primary lessons learned andconclusions include thefollowing: Paraffin actuators werefoundtobewellsuitedtotasksinvolving linearmotioninenvironments thatinclude dirt,waterandfrost.Whereactuation speedisnotaconcern, thesesimplereliable mechanisms provide highforceandsmalltomoderate lengthstrokeinacompact, lightweight package. Brushes andscrapers proved usefulinremoving excess soilparticles fromrunning surfaces. Futuremechanisms forapplication onMarsorsimilarenvironments shouldconsider incorporating thesecomponents. Ofthevarietyofdifferent soiltypestested,thosewithhardquartzorquartz-like crystals created themostdifficulty forsample delivery duetothetendency forhardcrystals tobecome jammed in tightclearances. Testing offuturemechanisms forsimilarenvironments shouldinclude these typesofmaterials. Frostprovedtobelessofaproblem thansoil.Itwasdealtwitheffectively byheating adjacent surfaces toremove thefrostlayer.Itwasalsofoundthatthinlayersoffrostwereeasilyscraped away. Ofthevarietyofsealstested,VitonTMo-ringsealsprovedtobethemosteffective forsealing linearshaftmovement inadirtyenvironment. O-rings provide enough compliance tosealaround micro-scratches andparticles. O-rings however shouldbecombined withscrapers andbrushes toprevent largeparticles fromintruding onordamaging theseal. •Reduction ofsqueeze provedeffective toreducestaticandrunning frictiontoacceptable levels forlinearshafto-ringseals.Reduction ofsqueeze shouldbedealtwithcautiously, however, because itrequires tightertolerance controlandmaycompromise lowtemperature sealing capability. •Inareduced pressure environment wheretheboilingpointissignificantly reduced, watercanbe pumped fromastorage container quiteeasilyandeffectively byheating thecontainer walls.This method shouldbeconsidered asarelatively simplemeansofmoving ordispensing waterin reduced pressure environments. AKaptonTMsealdiscandpuncture systemworked welltosealasolidreagent pelletfrom moisture. Kapton sealdiscsmaybeusefulforsimilarsealing applications. Despite earlyskepticism, thecoreless d.c.typemotorwasshowntoperform wellinvacuum. The useofvacuum-compatible lubrication wasthought tobekeytothissuccess. UsingacentralsolidmodelCADdesigner withinputfromseveral engineers worked wellinthis program tofitallofthecomponents intoaverytightpackage. 38
Low-Cost Ejection Mechanism forProtective Covers onMeteosat Second Generation J.Ortega*, F.Quintana*, G.Ybarra* Abstract Twocoversprotectthesensitive surfaces oftheMSG(Meteosat Second Generation 1)satellite against possible contaminants. Oncetheperilofcontamination ceases, thecoversmustbejettisoned, allowing thesatellite tooperate. Theirfailuretoprovide isolation orthefailureoftheirjettisoning leadstomission failure. Themechanisms responsible fortheejection mustfacesevererequirements: onlyonepyrotechnic is allowed forthebafflecover,theacoustic environment reaches levelsof146dB,andtheallowed massis verylow.Theserequirements haveledtotheuseofpreloaded supports suchasthe"flexible releasable hinge",whichiscapable ofsupporting thecoverandreleasing itpassively without theuseof telecommand. Introduction MSGmeteorological satellites willprovide meteorologists withimagery anddata.LiketheirMeteosat predecessors, theMSGsatellites willoperate fromgeostationary orbit.TheMSGmaininstrument isthe SEVIRI (Spinning Enhance VisibleandInfrared Imager). TheMSGrequire protection fortheiropticalsurfaces against contaminant particles duringground operations, transportation, launchandascenttothesatellite's transfer orbit.Twoindependent covers provide thisprotection (seelocation ofthesecoversonthesatellite inFigure1). Thecoversisolatetheinnercavities ofthesatellite, preventing anycontaminant fromentering and allowing theventing ofthegasinsidewhiletheeKternal pressure decreases. Oncetheperilof contamination ceases, thecoversmustbejettisoned, allowing thesatellite tooperate. Theirfailureto provide tightness orthefailureoftheirjettisoning leadstothelossofthemission. Requirements andsolutions Themostchallenging requirements forthejettisoning mechanisms were: •Onlyonepyrotechnic wasallowed tojettison thebafflecover.Thisrequirement limitsthenumber of supports forthecover,sincethesesupports mustbedetachable inordertojettison thecoverinorbit. •Theacoustic level,andthemechanical environment ingeneral, wereverysevereforahighstiffness andbarelysupported structure. TheSEVIRI EntryBaffleCoverhadtocoverapproximately 0.7m2,whichwastheaperture oftheBaffle. Nevertheless, sincethepressure outside thecoverwilldecrease duringlaunchandascent, thecoverdid notclosehermetically theinnercavity;aholewithafiltering devicewasrequired. Thefunction ofthe filtering devicewastoallowthedepressurization oftheinnercavityandatthesametimeprevent thedust fromentering. Dustwasaprimary concern andtheporesizeofthefilterwaslimited. *SENER Ingenieria ySistemas, S.A.,Spain Themechanisms &pyrossubsystem forMSGisaprojectdeveloped underaEuropean SpaceAgency / EUMETSAT contract. Theprimecontractor oftheMSGisAlcatelSpaceCannes. Proceedings ofthe34_Aerospace Mechanisms Symposium, Goddard SpaceFlightCenter,May10-12,2000 39
Figure1.Covers location ontheMSGsatellite Thejettisoning speedwasanimportant parameter fortheEntryBaffleCover. Ifitwereverylow,the covercouldimpactsomepartsofthesatellite suchasthesolarpanels, affecting itsperformance. Itwas defined thatajettisoning speedof1.5m/swouldbesufficient. Inthecaseofthebafflecover,thisspeed wasnotaprimary concern because thehighspinspeed(theMSGisaspin-stabilized satellite) willhelp thecoverachieve it. TheSEVIRI Passive CoolerCoverhadtocoverapproximately 1.9m2,whichwastheaperture ofthe SEVIRI Coolercone.Thiscoverdidnotclosehermetically theinnercavityeither. Thejettisoning speed wasalsoanimportant parameter andinthiscaseitwascriticalforthedesignofthejettisoning mechanisms. Theposition ofthecover,coaxial tothesatellite spinaxis,prevents itfrommaking useof thespin. TablelandTable2provide asummarized listofthemostimportant requirements. Preloading Theeasiest waytosupport adetachable coverisfixingitwithseveral pyrotechnically removable joints. Butinthiscase,thenumber ofpyrotechnic devices waslimitedtoone(bafflecover)orthree(cooler cover)andthesewerenotsufficient unlessadditional non-pyrotechnical supports wereadded. The solution chosen tosolvethisproblem wasusingsupport pointswherecontact wasensured applying a constant preload. Table1.SEVIRI entrybafflecoverrequirements summary SEVIRI ENTRYBAFFLECOVER ....S.UR.F.A..CE...T.Q BE....C..Q_RED.; ..................APPROX. 0.7mz TELECOMMAND: .,1PYROTECHNIC ............................................................................................ M_..,_.:P_._).-,!ZOPa .................................... JETTISONING SPEED: >1.5m/s MASS .<4K£ ................................................... MECHANICAL ENVIRONMENT i35gQUASISTATIC i25gSINE/27.3gRMSRANDOM .......................................................................................... L!.4,..6,.d_B,,............................................................................ ...T..H..E.R.M.._,E.N.Y.!..RP.,.N,M..E. NI"...........................-.6,Q°.,q..,Tq.+.6..q.°.,,C,. ................................................. STIFFNESS FIRSTMODEATF>140HZ Table2.SEVIRI coolercoverrequirements summary 4O
SEVIRI PASSIVE COOLER COVER I SURFACE TOBECOVERED iAPPROX. 1.9mz 1 "'_'_i_TiKi;_i--i'Kii_&";_AViW ..............T"i5"16"_;'"_"3............................................................... ] ....................................................................................... M..A_...p,..T.:P_x_)-!.7.0..Pa ..................I JETTISONING SPEED: >1.5m/s ..MA..S..S..................................................................... ..-<...!.0...K_................................................................ MECHANICAL ENVIRONMENT 15gQUASISTATIC 4gSINE/17.3GRMSRANDOM 146dB ...................................................................................... .8.0.9..DU.R.tN.G...0.:.8m. s.............................. ,.TH.E_MAL E_[RONM E._..................-6.0_o.C_TO...t..6...0...?. c........................................ STIFFNESS FIRSTMODEATF>60HZ SEVIRI passive coolerprotective cover. Thecoolercoverissupported atsixpoints: threepreloaded points(C)andthreepyrotechnically detachable support points(M).Thecoverisroundandallthesupport pointsaredistributed symmetrically ontheperimeter; between eachtwopyrotechnic mechanisms (M)thereisonepreloaded intermediate hardsupport point(C). COVER SYNOPSIS M-->Pyro rnech(jnism hordsu#por_ C->Intermediate herd support S->Kick springs Figure 2.Coversupport pointsanddistribution Thepreload intheintermediate hardsupport pointsisproduced bydeforming thecover(sandwich panel). Thedeformation ofthecoverisproduced joiningthetwopartsofthepyrotechnic mechanism (M).The gapbetween thesetwopartsiscalculated toproduce thedesired preload (seeFigure2&Figure3). Figure 3.SEVIRI coolercoverpreloading SEVIRI entrybaffleprotective cover. Thebafflecoverissupported atfivepoints(seeFigure4):fourpreloaded support points(CandH)and onepyrotechnically detachable support point.Thedesignofthepreloaded support pointsensured thatif thepyrotechnic wereactivated, thecoverwoulddetachcompletely. 41
HS HS M->Pyro mechonisrn hardsuppoFt C->lntermedio'te hord support S->Kick springs H->Hinge herdpoint HS->Hinge pre/ooding spring Figure4.Coversupport pointsanddistribution Forthesepreloaded supportjointstoworkproperly, thefollowing requirements mustbenecessarily fulfilled: •Thejoinedpartsmustbeeasilydetached withoutinterference andwiththelowestfrictionpossible. •Thejoinedpartsmustbekepttogether bytheactionofaforce(preload). Thisforcemustbehigher thanthemaximum separation effortthatmaybecausedbythethermalormechanical environments (vibration, acoustic, thermalloads). •Coldweldingmustbeavoided. Thepreload, inthesecovers,isapplieddeforming someelements ofthecover.Theworksequence is 1)"flexible hinge"preloading, 2)"kickspring"preloading, 3)panelpreloading, 4)launchandascent,and 5)jettisoning. Thissequence issimplerforthecoolercover.Thecoolercoverisjettisoned perpendicularly tothe mounting planeofthecover.Afterbeingjettisoned, thecovermovesparalleltoitselfasitdistances from thesatellite. Thisisnotthecaseforthebafflecover.Thebafflecover,oncethepyrotechnic cutterreleases thecover, rotatesaroundthehingesupport. Onceacriticalangleisachieved, thecovergetsdisengaged fromthe hingeanddistances freely.Therefore, inaddition tothetranslation ofthecoolercover,thebafflecover hasarotational motion. Figure5showsthisprocess schematically. 1)"Flexible hinge"preloading. Theflexiblehingeisaverysimpletitanium piecethatallowssupporting thecoveratonepointpreloading thejoint.Therearetwoofthesepieces,bothofthematthesameside ofthecover.Oncethecoverisengaged attheflexiblehinges,itisturneduntilthecontactisstabilized withthe"kickspring". 2)Kickspringpreloading. Thefunction ofthekickspringistoprovidetheinitialseparation speedonce thecoverisreleased. Duringthemounting ofthecover,thisspringmustbecompressed. 42
Figure5.1hi_geFle°(ur41 HS_ S preloacnncj ZK'ck--spnn9 _ pre_aad. S_ I ,_2 preload_l 2 IP2-X lP2/2-x/2 "r P21_-x12I HS_ s4Leunch wnvironment 5,.Jett.ieon_ 9 Structural andfunctional concept oftheSEVIRIentrybafflecover 3)Panelpreloading. Thepanelistheflatsurfaceofthecover.Thepanelhassomeflexibility; whenitis deformed toallowthebonding ofthetwopartsofthepyrotechnic mechanism, whichtogether areshorter thanthelateralsupportpoints,itproduces ajoiningpreloadattheselateralsupportpointsthatprevents thecoverfromseparating (seeFigure6). Figure6. 4)Launchandascent. Onceallthesupportpointsarepreloaded, thecoverisreadyforthelaunch environment. 5)Jettisoning. Thejettisoning operation isactivated byfiringthepyrotechnic cutter.Oncethepyroboltis cut,allthepreloads oftherestofthesupportpointsaredischarged andthecoverisreleased. •Thefirstpreloadtodisappear isthepreloadatthehardpoints(pointsCinFigure4).Whenthis preloadisdischarged, thecoverlosescontactwiththehardpoints. •Thekickspringwillcontinue pushingthecoverapartforsomedistance. Whenthecontactbetween thecoverandthespringislost,thebafflecoverwillstillcontinue rotatingaroundthehingeforasmall angle. •Thecriticalrotationangleisachieved andthecoverisdisengaged fromthehinge.Thecover distances freely. 43
Calculation Adetachable preloaded support canbetreated analytically asabonded pieceifthepreload issufficient. Themaximum external loadmustalwaysbelowerthanthepreload. Following thisstatement, calculating thepreload iseasyforstaticloads(orquasi-static). Forsineandrandom loadsitisabitmore complicated because acriterion mustbedefined; thepreload isaconstant forcewhilethesineorrandom loadsarenot.Dynamic forcesandtheireffectonpreloads wereanalyzed verysoonintheprojectandit wasconcluded that2_criterion wastheoptimum one.Theusual3_criterion couldhaveledtoan impracticable design. Thisconclusion wasconfirmed lateronbytest. Thepreloaded support_ thehinge Theflexible hinge(Figure7)oftheSEVIRI entrybafflecoverwasdesigned tofulfillthefollowing main requirements: •Maximum allowable volume: 60×35×124mm. •External loads:approximately 25%ofthetotalexternal load-acoustic environment wastheseverest loadcase-issupported byeachhinge. •Forthe"coverstowed" or"hingepreloaded" configuration thehingedesignconsiders thathingeparts willbeassembled withaprecision higherthan0.2deg.Thisvalueincludes allpossible deviations occurring duringmanufacturing, assembling orintegration. Thehingeitselfisnotresponsible for achieving thisprecision, andtherefore therestofthestructure mustensureit. •Itmustprovide onepointofsupport forthecoverduringallthephases ofthemission priortoarriving atthefinalorbit. •Itmustpassively allow,without interference andwithlimitedfriction(africtionbudget mustbe performed) thecorrectrelease andjettisoning ofthecover. Figure7.Flexible hingemechanism Themostoutstanding problems thatwerefacedduringthedesignofthehingewere: •Theallowable volume. •Thehighpreload required inordertoovercome theacoustic environment. •Thehingemustallowthejettisoning ofthecoverwithout interference. •Manufacturing withverytighttolerances toachieve therequired stiffness andstrength. •Coldwelding duetohighpreloads anddynamic environment. •Thefrictioncaused bytheslidingofthetwocontact surfaces whenthecoverturnsduringthefirst stageofthejettisoning. 44
Thehingeusedpreloadstobeareleasablehingeandastiffpointofsupportatthesametime.The preloadapplication isbasedontheleverprinciplesothatgoodprecisionandhighloadscanbeachieved withouttoomucheffort(Figure8). HShingespring Hhingesupportpoint Figure 8.Hingepreloading Precision Thehingeallowstherelative movement oftheconnected partsononlyonedegree offreedom. The translation degrees offreedom arerestrained, andinfactthehingeisverystiffforthosetranslations (stiffness varieswithdirection). Thetworotational degrees offreedom thatarerestrained arethose perpendicular tothehingeaxis.Thehingeisalsoverystiffforthoserotations. Thelastdegree offreedom, therotation around thehingeaxis,isfreealthough notcompletely. Thereis alowstiffness thatprovides thehingewithitspreload. Therefore, depending ontherelative position of thehingeanditsmatingpiece(seeFigure8),thepreload willbedifferent. Inthebafflecover,thisrelative position wasdefined duringtheassembly ofthepanelandthemechanisms (Figure 5). Geometry Thehingehasbasically twodifferent parts:thehingespringandthesupport. Thehingespringisinfact aflexible Titanium structure withanearlyconstant thickness, designed sothatitprovides therequired preload withlowstressandassmalldeformation aspossible. Thisflexible structure hasasemicircumference shape. Itcanbeeasilymodified tomeetdifferent preloads ordeformations. Thesupport isonlyapreloaded detachable support, asthosethatwillbedescribed in'1:)reloaded supports: hardpoints". Bothpartsmustbelocated atprecise locations sothatabsence ofinterference isensured duringrelease. Anerrorononeofthedimensions thatdefinetherelative position ofthehingespringandthesupport maymeanthatthecoverwillgetstuckinstead ofbeingjettisoned. Thesurfaces incontact Inordertoavoidthecoldwelding orsimilarundesired effectsthatcouldhaveanimpactonthecorrect release ofthecovers, onesideofthedetachable pieceswascoatedwithTiC(titanium carbide). The contact surfaces ofthehingesupport anditsmatingpiecemustbedesigned performing atrade-off between thesetwopoints: •Thecontact surface cannotbeaflatsurface against another flatsurface, sincethiskindofcontact surface cannotwithstand forcesinaplane(oronlybyfriction). 45
•Thecontactsurfacecannotbeaconeagainstaconeorsphereiftheapertureoftheconeissmall andcausesbondingduetofriction. Theconclusionofthistrade-offmustbetheapertureangleofacone: •Closedenoughsothateverylateraloraxialloadiswithstoodwithoutthesurfacesdetaching(fora givenpreload). •Openenoughsothatthecontactsurfacesdonotgetstuckduetofriction(foranypreload). Therelease Fromthehingestandpoint, thefunctional sequence ofthejettisoning is: •Oncereleased, thecoverlosescontact withthehardpointsandthekickspring. Uptothispoint,the coverhasturnedaroundthehinge. •Thecovercontinues rotating aroundthehingeuptothecriticalangle.Duringthisrotation thereis frictionbetween thetwosurfaces incontact. Thepreload produced bytheflexible hingeitselfcauses thisfriction. Nevertheless, sincethepreload decreases astheangleischanging, thefrictionalso decreases. •Thereisanangle,between the"lossofcontact withkickspring" angleandthecriticalangleforwhich thepreload iszero. •Thecoverlosescontact withthehingeanddisengages. Thisprocess wassimulated withdetailsothatpossible interference couldbeknowninadvance. Asa resultofthissimulation, somedimensions andanglesweremodified inordertoimprove thesuccess reliability. Manufaqturinq qfthehinge Eachhinge,afterbeingmanufactured, wastestedtomeasure itsstiffness onthetwobasicdirections and itscapability ofbeingreleased without interference andlowfriction(Figure 9).Withtheresultsobtained fromthesetests,thematingpiecesweredesigned andeventually manufactured. Figure 9.Hingecharacterization test:release test Figure 10.Hingecharacterization test:stiffness test 46
Preloaded supports: hardpoints Hardpoints(Figure 11)located infrontoftheflexible hinges, arecomposed oftwodetachable parts:on thecoverside,aconeandonthesatellite side,asphere. Thiskindofcontact provided thesupport ofthe coverwhensubmitted tothethermal andmechanical environments andatthesametimemadeit possible forthecovertoseparate without interference orfriction. Theaperture oftheconeisdesigned by performing atrade-off, inthesamewayasfortheflexible hingesupport (explained above). Figure 11.Hardpoints Thistrade-off, performed forthehardpoints,concluded thattherewasnoanglethatfulfilled both conditions atthesametime.Theanglesthatareopenenough nottocausefrictionproblems during detachment werenotenough toabsorbtheexternal lateralloads.Thisproblem wassolvedusingtwo aperture angles(twodifferent coneswithtwodifferent aperture angles) atthesametime.Oneofthe angleswascalculated suchthatitwouldbeopenenough toprevent sticking duringthedetachment, while theotheronewascalculated suchthatitwasclosedenough toprevent detachment duetothe environmental loads.Therefore, thecovercontact surface, asshowninFigure12,isnotapurecone. Figure 12.Hardpoints, contact surfaces Pyrotechnic support Thefifthsupport point(seeFigure13)ismainlycomposed ofadoublepyrotechnic cutterandarod.The pyrotechnic cuttertojettison thecovercutstherod. Duringtheintegration ofthecover,andaftersupporting itbythetwohingesandthetwohardpoints,a gapexistsbetween thefixedandjettisonable parts.Thisgapisabsorbed deforming thepanel,and therefore applying apreload totherestofthesupports (especially thehardpoints). 47
Figure 13.Pyromechanism andhardpoints Jettisoning Oncethecoversarenotneeded (onceintransfer orbit),theymustbeejected. Themainrequirement of theejection isnotcausing damage tothesatellite. Forthistohappen, aminimum ejection velocity is required andtheejection direction mustbesuchthatnointerference existswithanyotherpartofthe satellite. Sincetherelease ofthecoversisveryimportant forthemission ofthesatellite, thisoperation hasbeen designed withredundancy. Inthecaseofthebafflecover,thelevelofredundancy isuptothree:the pyrocuttersarefullyredundant andtheseparation isproduced bythreedifferent forces,thespinofthe satellite, thedeformation ofthecoveritself,andthekickspringlocated nexttothepyrotechnic. Thejettisoning process hasbeensimulated usingSENDAP 2software. Figure14showstheevolution of theseparation speedanddistance between thebafflecoverandthesatellite. Afterperforming the qualification tests,thefinalseparation speedwasdemonstrated tobe15.6m/s. Bafflecoverejection (nodelay,90rpm) I/2_ Detachment ''iI0Figure 14.I I I 0,3000 0.4000 05000 time(s) SEVIRI entrybafflecoverejection simulation Figure15showstheevolution oftheseparation velocity forthecoolercover. Inthiscase,one pyrotechnic failurehasbeenconsidered. Thesimulations demonstrated thatthejettisoning fulfilled allthe requirements, namely absence ofinterference andminimum jettisoning speed. Thetestsconfirmed this factduringthequalification stage. 2SENDAP standsforSENER dynamic analysis program. Thissoftware iscapable ofsimulating very complex dynamic situations. Itwasdesigned tosimulate thedocking /berthing ofspacecraft anditwas qualified fortheHERMES spaceplaneprogram. 48