1. 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]

2. AAE450 Spring 2009 Power Systems Update  Solar Cells  Max. Potential Power = 253 Watts  Area = 0.785 m 2 –Cells are extremely thin  Weight = 2 kg  Cost = $235,000  Battery  Power available = 101.6 Watts  Dimensions = 0.142 m X 0.0534 m X 0.1502 m  Weight = 0.64 kg  Cost = $2,000 [Adham Fakhry] [Power] 2

3. 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 10-15 –From 0.044 W/m 2 K 4 to 0.000112 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 5215.98 Watts to dissipate and will need 1804.19 kg of hydrazine to survive the night [Adham Fakhry] [Power] 3

4. 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 = 0.142 m X 0.0534 m X 0.1502 m  Cost $2000 per cell  From Yardney - Lithion [Adham Fakhry] [Power] 4

5. 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

6. 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

7. 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= 12096000 Joules  H rxn = -112093 J/mol = 3502916 J/Kg  Mass of Hydrazine = 3.45 kg [Adham Fakhry] [Power] 7

8. AAE450 Spring 2009 Backup Slide 5  With 7 mm MLI and K = 0.044 W/m 2 K 4  Losing 5215.98 Watts  With Hydrazine providing only 13.5 X 10 6 Joules, would need 1804.19 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

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

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

11. AAE450 Spring 2009 Backup Slide 8  Using the Effective Emissivity equation and assuming that the ML will have an emittance of 0.005.  Thickness of MLI is 10 mm, and the T C is 143 K and T H is 273 K.  Thermal conductivity = 0.000112 W/m 2 K 4  Heat lost through Lander by using Heat transfer equation = 9.95 W  Surface area of Lander = 6.054 m 2 [Adham Fakhry] [Power]

12. AAE450 Spring 2009 Backup Slide 9: References  References: –http://www.yardney.com/http://www.yardney.com/ –http://nmp.jpl.nasa.govhttp://nmp.jpl.nasa.gov –http://www.aec- able.com/corpinfo/Resources/ultraflex.pdfhttp://www.aec- able.com/corpinfo/Resources/ultraflex.pdf –http://www.spectrolab.com/http://www.spectrolab.com/ –Spacecraft Thermal Control Handbook –Transport Phenomena in Materials Processing –Space Propulsion Analysis and Design [Adham Fakhry] [Power Group] 1`