wire.Fromthismechanical testing,itwasconcludedthattheetchingprocesswiththeAD-485solutiondid notadverselyaffectthemechanical propertiesofthewire,andtheseetchedwireswouldbeableto consistently supporttheloadrequirements fortheBurnWireMechanism. Electricaltestingofthesampleswasperformedtodeterminetheelectricalcharacteristic thatwouldbe requiredtoefficientlybreaktheburnwireattheetchedportionofthesample.Similartothemechanical testing,thealuminumretaineridenticaltotheoneusedinthemechanism wasusedintheelectricaltests withtheburnwiresamplethreadedthroughit.Apreloadofapproximately 9Nwasapplied tothe aluminum retainer. Initialtestingofboththe0.20-mm and0.30-mm wirebeganat28.8Vand7.5A,which isastandard setting onmostsatellites. Bothtypesofwiresuccessfully brokeattheetching. Some damage tothealuminum retainer wasobserved duetothelargevoltage running through theburnwire beforebreaking. Also,thewiredeveloped ablackcarbon likedeposit onit.Minimum powerrequirements weredetermined nextandareshowninTable4.Arangeofampsandvoltage canbeaccommodated withthismechanism andthewirediameter andetchdiameter canbechanged toaccommodate alower settingifneeded. Table4.BurnWireElectrical Tests Wire Etch LowPower Optimum HighPower Diameter Diameter Setting PowerSetting Limit 7.5amps@ 7.5amps@ 28.8amps@0.3mm7.5volts 7.5volts 7.5volts 7.5amps@ 7.5amps@ 28.8amps@0.3mm7.5volts 7.5volts 7.5volts 6amps@ 10amps@ 28.8amps@0.2mm0.18mm8volts 15volts 7.5volts 5amps@ 7.5amps@ 28.8amps@0.2mm0.15mm5volts 7.5volts 7.5volts Finally, aftertheinitialthreesetsoftests,actualtestsofthemechanism inasimulated operational setup wereconducted. Alloftheinformation abouttheperformance ofthebumwirefromtheprevious three setsoftestswasincorporated intothemechanism. Thesetupforoperational testing calledforthe assembly oftheactualmechanism itselfandinstalling itintoamockinstrument cover. Applied current tothemechanism caused theburnwiretobreakaspredicted attheetchedareaofthe wireandtheinstrument covereasilydeployed. Thisprocess wascompleted over20timeswiththe0.20mmwireetched to0.15mm.Asfortheoperational testswiththe0.30-mm samples, manytimesthe current required tobreakthewireanddeploythecovercaused theburnwiretowelditselfintothe aluminum retainer andrestrictthecoverfromopening. Thisperformance ofthe0.30-mm wireproved againthatthisconfiguration wasnottheoptimal waytoassemble theBurnWiremechanism. One unexpected problem withtheBurnWiremechanism thatwasencountered inboththe0.20-mm and0.30mmconfigurations wastheoccurrence ofelectrical arcsfromthewireitselftoportions oftheinstrument cover,attachment bracket, oreventhemechanism itself.Thiswasanoticeable problem intheoperation ofthemechanism, butonethatcanberesolved withchanges inmaterial selection ofcomponents. Overall, theBurnWiremechanism performed extremely wellduringoperational testing. Aswithallnew technologies, problems wereencountered; however, theseproblems areseenasonesthatrequire minor designchanges ratherthanoverallchanges thatcouldaffectotheraspects ofthemechanism thathave already beentested. Recommendations forFutureDevelopment Usingnon-conducting materials inthemechanism wouldminimize shorting damage. Shorting ofthewire overtoaninstrument isanunacceptable problem forthisdesign, especially whenintegrated with sensitive instruments several shortsoccurred duringtests.Components thatweredamaged andany othersthreatened bypossible shorting orarcingcouldbemadefromaceramic togiveitthestrength and electric isolation needed toprevent suchaproblem. Thehousing, whichisacriticalcomponent ofthe 295