120 likes | 249 Views
Lunar Night and Lander Power System. Adham Fakhry February 26th, 2009 Power Group Lunar Descent Phase Passive Thermal Control for Lunar Night and Powe r systems for Lander. Power Systems Update. Solar Cells Max. Potential Power = 253 Watts Area = 0.785 m 2 Cells are extremely thin
E N D
Lunar Night and Lander Power System AdhamFakhry February 26th, 2009 Power Group Lunar Descent Phase Passive Thermal Control for Lunar Night and Power systems for Lander [Adham Fakhry] [Power]
Power Systems Update • Solar Cells • Max. Potential Power = 253 Watts • Area = 0.785 m2 • 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]
Lunar Night Thermal Control [Adham Fakhry] [Power] • 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/m2K4 to 0.000112 W/m2K4 and increase MLI thickness to at least 10 mm • In order to allow only 10W 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
Backup Slide 1 - Battery Specifications [Adham Fakhry] [Power] 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
Backup Slide 2 - Battery Design [Adham Fakhry] [Power] • 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
Backup Slide 3 - Passive Thermal Control [Adham Fakhry] [Power] • 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
Backup Slide 4 - Heats of Reaction Calculations [Adham Fakhry] [Power] 10 W 14 days =10W∙14 days∙24 hrs/day.60 min/s.6 secs= 12096000 Joules Hrxn = -112093 J/mol = 3502916 J/Kg Mass of Hydrazine = 3.45 kg
Backup Slide 5 [Adham Fakhry] [Power] With 7 mm MLI and K = 0.044 W/m2K4 Losing 5215.98 Watts With Hydrazine providing only 13.5 X 106 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
Backup Slide 6 [Adham Fakhry] [Power]
Backup Slide 7 [Adham Fakhry] [Power]
Backup Slide 8 [Adham Fakhry] [Power] 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 TC is 143 K and TH is 273 K. Thermal conductivity = 0.000112 W/m2K4 Heat lost through Lander by using Heat transfer equation = 9.95 W Surface area of Lander = 6.054 m2
Backup Slide 9: References [Adham Fakhry] [Power Group] • References: • http://www.yardney.com/ • http://nmp.jpl.nasa.gov • http://www.aec-able.com/corpinfo/Resources/ultraflex.pdf • http://www.spectrolab.com/ • Spacecraft Thermal Control Handbook • Transport Phenomena in Materials Processing • Space Propulsion Analysis and Design