AAE450 Spring 2009 Lunar Night and Lander Power System Adham Fakhry February 26th, 2009 Power Group Lunar Descent Phase Passive Thermal Control for Lunar Night and Power systems for Lander [Adham Fakhry] [Power]

AAE450 Spring 2009 Power Systems Update  Solar Cells  Max. Potential Power = 253 Watts  Area = m 2 –Cells are extremely thin  Weight = 2 kg  Cost = $235,000  Battery  Power available = Watts  Dimensions = m X m X m  Weight = 0.64 kg  Cost = $2,000 [Adham Fakhry] [Power] 2

AAE450 Spring 2009 Lunar Night Thermal Control  Will use Hydrazine  Need to decrease the thermal conductivity of the Multi- layered Insulation. –Can be accomplished by increasing the number of polished Aluminum Mylar Layers from 1 to –From W/m 2 K 4 to W/m 2 K 4 and increase MLI thickness to at least 10 mm  In order to allow only 10 W heat to escape from Lander  With this system, will need 3.45 kg of Hydrazine to heat the Lander for Lunar Night  Current system will allow Watts to dissipate and will need kg of hydrazine to survive the night [Adham Fakhry] [Power] 3

AAE450 Spring 2009 Backup Slide 1 - Battery Specifications  3.6 V, 20 Ah Lithium Ion Cell  Gives 72 W-hr only need 44 W-hr  Energy Density = 140 W-hr/kg  Dimensions = m X m X m  Cost $2000 per cell  From Yardney - Lithion [Adham Fakhry] [Power] 4

AAE450 Spring 2009 Backup Slide 2 - Battery Design  Battery is designed for meet four power goals: –Delivers 100 W for 450 seconds for operating the Lander engine –Delivers 35 W for 450 seconds of heating the propellant –Delivers 40 W of cooling for 500 seconds (if need be) –Delivers 44 W for 30 minutes for all communication gear [Adham Fakhry] [Power] 5

AAE450 Spring 2009 Backup Slide 3 - Passive Thermal Control  Cost around $24,000 for every kg to the moon  In interest of saving cost, choose Hydrazine instead of hydrogen Peroxide –Save $96,000 by using Hydrazine –Need 3.5 kg on Hydrazine to heat Lander for 2 weeks of Lunar Night [Adham Fakhry] [Power] 6

AAE450 Spring 2009 Backup Slide 4 - Heats of Reaction Calculations  10 W 14 days =10W∙14 days∙24 hrs/day.60 min/s.6 secs= Joules  H rxn = J/mol = J/Kg  Mass of Hydrazine = 3.45 kg [Adham Fakhry] [Power] 7

AAE450 Spring 2009 Backup Slide 5  With 7 mm MLI and K = W/m 2 K 4  Losing Watts  With Hydrazine providing only 13.5 X 10 6 Joules, would need kg of hydrazine to keep Lander warm  Need to decrease thermal conductivity of MLI by increasing number of polusihed Aluminum layers [Adham Fakhry] [Power] 8

AAE450 Spring 2009 Backup Slide 6 [Adham Fakhry] [Power] 9

AAE450 Spring 2009 Backup Slide 7 [Adham Fakhry] [Power] 10

AAE450 Spring 2009 Backup Slide 8  Using the Effective Emissivity equation and assuming that the ML will have an emittance of  Thickness of MLI is 10 mm, and the T C is 143 K and T H is 273 K.  Thermal conductivity = W/m 2 K 4  Heat lost through Lander by using Heat transfer equation = 9.95 W  Surface area of Lander = m 2 [Adham Fakhry] [Power]

AAE450 Spring 2009 Backup Slide 9: References  References: – – – able.com/corpinfo/Resources/ultraflex.pdfhttp:// able.com/corpinfo/Resources/ultraflex.pdf – –Spacecraft Thermal Control Handbook –Transport Phenomena in Materials Processing –Space Propulsion Analysis and Design [Adham Fakhry] [Power Group] 1`