Background Ithasbeenobserved inpastMarsmissions thatdustcollecting onsolarcellsusedontheMartian surface rapidly blocks solarenergy andleadstoeventual spacecraft failure. Theexperiments ontheupper surface ofMIPweredesigned tobettercharacterize thedustcollection phenomenon, andconsisted ofa number ofsmallsolarcellsandradiator panels mounted ontheupper,stepped surface oftheMIP experiment enclosure. Anumber ofsolarcellsandassociated equipment werepresent toassess general cellperformance anddustcollection ratesaswellastoattempt dustmitigation techniques. •Several different typesofsolarcellswereincluded toassess theirperformance intheMartian environment andtheirsensitivities todustaccumulation. (MATE) •Several cellsweremounted onsurfaces ofdifferent slopestodetermine ifthedustmightslideoff. Several cellswereset-upnearsuspended wiressuchthatsmallelectrostatic fieldscouldbeusedto attempt torepeldustfromaspecific area.(DART) •Twosmallradiator panelswereopentotheMartian skytoassess thermal radiation characteristics anddusteffects. (MTERC) Inallcases,theintentwastoestablish baseline operating performance foreachexperiment andthen monitor performance andpotential degradation asenvironmental dustcollected oneachcell. Indesigning theexperiments, itwasveryimportant tobeabletohavereasonable knowledge ofinitial dustloading andthereby toreasonably establish theinitialoperating conditions ofthecells(initialdust loading wasexpected tobezeroornearzero).Throughout theevolution ofthedesignoftheexperiments, thepossibility oftheneedforacoverhadbeenraisedanddiscussed several times.Itwasinitiallyunclear whether ornotacoverwasneeded andtheaddedmassandcostpushed thecoverintothe"wereally don'tneedthat"zone.Inaddition, theexperiments werehoused inaverytightlypacked landing vehicle and,basedonalltheenvelope constraints, therewasnotanyroomforacover. Lateinthedesign process forMIPandtheupperpanelexperiments therecurring coverconversation was,onceagain,renewed. Inanattempt toresolve theissuemoredetailed analyses ofthelanding conditions wereundertaken. Whilesomestillthought thattheriskofdustaccumulation duringlanding wasminimal, acredible analysis indicated thatthelanding thrusters wouldstirupaverylargedustcloud. Undercertain conditions, thisdustcouldsettleanddeposit uptoamillimeter ofdustontheupper surfaces ofthespacecraft andinstruments. Ifthiswerethecasetheuncovered experiments wouldbe finished beforetheybegan.Basedonthisanalysis several landermission experiments (including theMIP module aswellastherover)thatmightbesensitive tothisdustadopted thestrategy thatiftherewasany waytoretrofittheexperiment andstillfitwithinthespacecraft, adustcoverwastobeincluded. Inthe caseoftheMIPmodule, NASA-JSC, Lockheed Martin, andStarsys beganworking closely together to determine ifacoverfortheexperiment wasevenfeasible. Design problems Instrument requirements Thethreeexperiments onthetopsurface oftheMIPmodule needed tobeprotected fromswirling dust duringlanding andsettling dustaftertouchdown andengineshutdown. Withallofthevarious solarcells andpanels, thesurface wasveryuneven andnon-symmetrically shaped. Insomewaystheuppersurface resembled acityblockwithbuildings ofdiffering sizesandheights. Thecoverwouldneedtoprotect allof theseinstrument features without touching ordamaging them.Tomaketheproblem moredifficult, the surface consisted ofseparate sections atdifferent levels.Tomaximize exposure totheMartian skyand viewofthesun,thefield-of-view fortheexperiments required thatthecovernotblocktheviewabove15 degrees fromtheplanesofthesurface sections. Because protection fromswirling dustwasnecessary, thecoversystem alsoneeded toprotect theside aspects oftheuppersurface andexperimental sections. Thesidesections needed tobetallenough to support thecoverabovetheexperiment components. Inseveral areassiderailsusedtosupport the 72