AAE450 Spring 2009 Translunar 97.6% Lunar Descent/Locomotion 93.8% Earth->LEO 94.1% – 99.2% Reliability Launch vehicle (Dnepr) Launch vehicle (Delta II) Solar array EP Propulsion Battery Antenna Processor LD Propulsion Structure Mechanical Propulsion Antenna 94.1%91.8%86.1% Recommend 1.Modify Launch Vehicle reliability calculation model 2.Modify >90% reliability requirement Phase Reliability New system failure modes Dnepr Reliability 99.2%96.8%90.8% Delta II Reliability [Solomon Westerman] [PM] 2 Carry-through Reliability Mission reliability expected to increase with total system mass
AAE450 Spring 2009 Reliability Calculation VariableDescription PlvProbability of launch vehicle success SNumber of successful launches LTotal number of launches TNumber of successful launches of stage (heritage) nNumber of stages (must be > 1), this is included to mitigate multiple stages causing very low success rate Launch Vehicle > 20 launches < 20 launches w/ heritage VariableDescription PtlProbability of translunar success CNumber of insurance claims on SB LTotal number of launches of SB F1yPercent of SB failures within one year SfProbability of individual system failure TMFProbability of individual system failure causing total mission failure Translunar Based on GEO Satellite Buses (SB) (optimistic) VariableDescription PllProbability of lunar descent / locomotion success SNumber of Mars lander or rover mission successes from 1996 onwards TTotal number of Mars lander or rover missions from 1996 onwards Lunar Descent / Locomotion (estimated) [Solomon Westerman] [PM] 3
AAE450 Spring 2009 Backup Slides Dnepr launch data: Booster reliability 97% (http://www.astronautix.com/lvs/r36m.htm)http://www.astronautix.com/lvs/r36m.htm Delta II launch data: 125 successes 126 attempts (http://www.astronautix.com/lvs/delta.htm)http://www.astronautix.com/lvs/delta.htm Satellite bus data based off LMT-A2100 –Similar power capability and propulsion system –Power and propulsion two most important failure modes –TMF data from A2100 failure modes (http://www.skyrocket.de/space/doc_sat/lockheed_a2100.htm)http://www.skyrocket.de/space/doc_sat/lockheed_a2100.htm –System failure data from industry study by Frost & Sullivan (2004) (http://www.satelliteonthenet.co.uk/white/frost3.html )http://www.satelliteonthenet.co.uk/white/frost3.html Failure breakdown by subsystem (modified data from Frost & Sullivan)
AAE450 Spring 2009 Backup Slides (II) Lunar Descent / Locomotion success based on recent (1996+) US Mars lander / rover successes. –Mars Pathfinder (1996-1997) Success –Mars Polar Lander (1999) Failure –Spirit (2003) Success –Opportunity (2003) Success A factor of 1/4 is to reduce the percentage of failure to 1/4 that of Mars missions. –Low sample size for lander / rover on Mars –Lunar missions less complex (no atmosphere, lower orbital velocities to mitigate) –Success/Total ratio for Mars missions is based on total mission success – not just descent/locomotion. The rest of the mission success has already been computed for the Lunar mission.
AAE450 Spring 2009 Reliability Analysis Numbers based on industry analysis by Frost + Sullivan http://www.satelliteonthenet.co.uk/white/frost3.htm l Lockheed Martin Space Systems A2100 bus is most similar in power and propulsion systems for GEO satelliltes. LMT A2100 Successful Launches23satellites Insurance Claims3claims Percent of failures occuring in one year 44percent Failure Breakdown - All satellites % of failuresApplicable?% TMF* Solar38percentYes25percent9.5 Prop15percentYes100percent15 Payload Electronics13percentNoN/A Battery11percentYes50percent5.5 Antenna9percentYes50percent4.5 Transponder6percentNoN/A Processor6percentYes100percent6 Structures2percentYes100percent2 42.5 * TMF (Total Mission Failure) Expected Failure Probability 2.4%Percent Expected Success Probability 97.6%Percent Backup Slides (III) Translunar Reliability Calculation
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