AAE450 Spring 2009

Lunar Lander Power Systems

Adham Fakhry

Power Group

Lunar Descent Phase

[Adham Fakhry] [Power Group]

AAE450 Spring 2009

Solar cells for Lunar LanderUltraflex Solar cells From Able Engineering Efficiency = 30% 1000 $/Watt 150 W/kg Mass = 1.57 kg Power = 236 W Area = 0.78 m2

Cost = $235,620

Ultra Triple Junction Cells From Spectrolab Efficiency = 28.3% 330 W/m2, 400 $/Watt (for

2kW – 5Kw range) 2.06 kg/m2

Mass = 1.362 kg Power = 218 W Area = 0.661 m2

Cost = $87,200

[Adham Fakhry] [Power Group]2

AAE450 Spring 2009

Battery for Lunar Lander To survive a Lunar night, need 5 W for

standby power– 145 W-hr/kg. Need 1680 W-hr to survive 14 days.– Need a 11.5 kg battery to meet this requirement, in

order to survive the night.– Desired total mass of battery structure: 20 kg

• (Insulation, Support Struts, Battery, Power Management and Distribution System)

– Batteries obtained from Yardney – Technical Products.

[Adham Fakhry] [Power Group]3

AAE450 Spring 2009

Backup Slide 1: Solar Array Grid

[Adham Fakhry] [Power Group]4

1.0 m

0.7071 m

0.7071 m

0.357 m

0.113 m

AAE450 Spring 2009

Backup Slide 2: Power Sys. Prop.

[Adham Fakhry] [Power Group]

Properties Solar Cells Batteries

Mass 1.362 kg 20 kg = 11.5 kg batteries + structure + Power Management and Distribution system

Power 218 W (Maximum potential power)

6,048,000 W or 1680 W-hrs

Cost $ 87,200 Awaiting return from Yardney

5

AAE450 Spring 2009

Backup slide 3: Battery Sizing Calculation for battery: Need 5 W for standby power

– Mass Battery = 145 W-hrs/kg– Days of use = 14 days = 336 hrs– Usage = 5 X 336 = 1680 W-hrs– Mass = 1680 / 145 = 11.6 kg

Battery needs power distribution system, for managing power and dropping the voltage for other systems, such as camera, coolers, etc.

[Adham Fakhry] [Power Group]6

AAE450 Spring 2009

Backup slide 4: Solar Array sizing Solar array Calculations: Dimensions of Solar cells:

– Area of Lander roof = π(1/2)2 = 0.785 m2– Solar efficiency = 300 W/m2– Potential max power = 235.6 W

Cost of Solar Cells:– Cost of cells per watt = 1000 $/W– Cost of Cells = 235,619.45 = $235,600

[Adham Fakhry] [Power Group]7

AAE450 Spring 2009

Backup slide 5: Solar Array sizing 2 Solar array Calculations:

Dimensions of Solar cells:– Total area = 0.661 m2

– Weight /area = 2.06 kg/m2

– Total weight = 1.362 kg Cost of Solar Cells:

– Cost of cells per Watt = 400 $/W– Cost of Cells = $ 87,200

[Adham Fakhry] [Power Group]8

AAE450 Spring 2009

Backup slide 6: Cost per block Solar array Calculations: Cost of Solar Cells:

– Cost of cells per block: $300 per block– Block sizes range from 26.62 cm2 to 29.85 cm2– Average number of blocks = 360– Total cost of solar cells = 70,200

[Adham Fakhry] [Power Group]9

AAE450 Spring 2009

Backup slide 7: Potential Power

[Adham Fakhry] [Power Group]10

AAE450 Spring 2009

Backup slide 8: References References:

– http://www.yardney.com/– http://nmp.jpl.nasa.gov– http://www.aec-able.com/corpinfo/Resources/

ultraflex.pdf– http://www.spectrolab.com/

[Adham Fakhry] [Power Group]1`