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Power Systems Sizing. Ian Meginnis January 29, 2009 Group Leader - Power Systems. Battery Sizing. Secondary batteries used for lunar lander (LL) and rover Size of LL batteries dictated by power requirement for 2 weeks of darkness LL battery mass =~ 23 kg
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Power Systems Sizing Ian Meginnis January 29, 2009 Group Leader - Power Systems Ian Meginnis Power Systems
Battery Sizing Ian Meginnis Power Systems • Secondary batteries used for lunar lander (LL) and rover • Size of LL batteries dictated by power requirement for 2 weeks of darkness • LL battery mass =~ 23kg • Based on requirement of 10 Watts for 2 weeks • Mass of rover batteries based how much power is needed prior to solar array deployment • Occurs soon after landing • Rover battery mass =~ 0.5kg
Data from Busek Co. Inc. Ian Meginnis Power Systems
Backup Slide Ian Meginnis Power Systems • Calculation of battery size for LL: • Li-ion Energy Density: 145 Wh/kg • Thermal Power Requirement: ~10 Watts • Total Time in Darkness: 2 weeks (336 hr) • Battery Mass = 336hr * 10W / 145Wh/kg = 23 kg • Calculation of solar array sizing for rover: • Need to power several devices: • Turn on and operate computer (RAD6000): ~10W; 1.0hr • Egress LL: ~10W; 1.0hr • Solar array deployment: ~6W; 1.0hr
Backup Slide (cont.) Data from Busek Co. Inc. Ian Meginnis Power Systems • Solar arrays comprised of triple-junction Gallium Arsenide (GaInP2/GaAs/Ge) • Produce ~300W/m2 • Busek Hall-Effect Thrusters: