AAE450 Spring 2009

Lunar Night and Lander Power System

Adham FakhryFebruary 26th, 2009

Power GroupLunar 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 = 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]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 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 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

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

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= 12096000 Joules Hrxn = -112093 J/mol = 3502916 J/Kg Mass of Hydrazine = 3.45 kg

[Adham Fakhry] [Power]7

AAE450 Spring 2009

Backup Slide 5 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

[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 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

[Adham Fakhry] [Power]<#>

AAE450 Spring 2009

Backup Slide 9: References 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

[Adham Fakhry] [Power Group]1`