Abstract: Inthebrutaltemperatureenvironmentinmoonsurfacewiththerangeof-180℃to90℃,itneedstosolvetheLunarBasedUltravioletTelescope（LUT）heatdissipationduringlunardaytimeandheatpreservationduringmoonlitnightwithoutelectricenergysupply.Inordertosolvetheheatconsumptiontransmission,discharge,andtheheatpreservationproblemofmoonnight,apassiveheatpipethermalswitch（HPTS）wasproposedasameansoflongdistanceheattransferbetweenthedeviceandtheradiator,accordingtothephasetransitioncharacteristicsoftheworkingfluid.Dependingontheequipmenttemperatureindex,aworkingfluidwithsuitablefreezingpointandheattransfercapacitywasselected.TheHPTSwasfilledwithworkingfluid,whichcantransmitenergyfromevaporatortocondenserbyphasechange.Inextremelylowtemperatureofthenight,theworkingfluidisfrozen,itcausestheconnectiontobeinterrupted,andthentheLUTcanbemaintainedabovethesurvivaltemperature.IthasbeenproventhroughthegroundtestandinorbitresultthattheswitchingratioofHPTSisgreaterthan30nearthefreezingpoint.Ataworkingtemperatureof7℃,theheattransfercapacityofHPTSisgreaterthan15W,andheattransfertemperaturedifferenceislessthan4℃.Inaddition,theHPTScanaccommodateLander′stiltof±15°.AllthepropertiesoftheHPTSensurethattheLUTonLanderworksinorbitwithhighperformance.

Key words: Chang′E3Lander, lunarbasedultraviolettelescope, heatpipethermalswitch, conductanceratio