Abstract: Areliabilityvalidationtestmethodandaconservativereliabilityassessmentmethodforpyrotechniccutterswereputforwardbasedoncharacteristicparametermeasurementswithsmallsamples.Ascharacteristicparameters,thepeakgas-pressuresofthecutterintheratedcondition(bilateralignition)andintheunilateralignitionconditionweremeasuredinthetest.Basedonthegeneralizedstrengthstresstheory,thereliabilityassessmentwascarriedoutbytestdatawithsmallsamples.Theproposedreliabilityvalidationtestmethodnotonlyavoidsconsumingmoretestproductstoobtaincriticalvaluedistributionofthecharacteristicparameters，butalsoutilizescharacteristicparametervariablesinsteadofcountingthesuccess numberofsamples.Besides,Thismethoddoesn′tneedartificialintensificationcoefficients.Hence,thereliabilityassessmentresultscanreflecttherealreliabilityleveloftheproductsintheworseworkingconditions.Anapplicationexamplewasgiven,inwhichonly60testsamplesofthepyrotechniccutterwereusedforthereliabilityvalidationtestandthereliabilityassessment.Themethodcontributestothesmallsamplereliabilityassessmentofpyrotechnicdevicesinspacecraft.

Key words: Pyrotechniccutter, Reliabilityvalidation, Smallsample, Reliabilityassessment, Spacecraft