1. Structures and Thermal Lunar Descent Phase
Kelly Leffel 2/19/09
Structures and Thermal
Lunar Descent Phase
Kelly Leffel Structures and Thermal 1

2. Kelly Leffel Structures and Thermal
Updated Mass – Volume
Wet Lander Mass
321.2 kilogram(kg)
Dry Lander Mass
162.2 kg
Dimensions (Height, Top Diameter(d), Base d)
1 meter(m), 1.33 m, 2 m
Area for Solar Array
1.39 m^2
Moments of Inertia
Izz
107.2 kg-m^2
Iyy = Ixx
70.3 kg-m^2
Ixy = Iyx
-53.6 kg-m^2
Izx = Ixz = Izy = Iyz
-31.2 kg-m^2
Kelly Leffel Structures and Thermal

3. Kelly Leffel Structures and Thermal
Thermal Control
Current (Active/Passive Approach)
MLI blanket – 1.5 kg
Cryocooler – 8.1 kg and requires 40 W
Kelly Leffel Structures and Thermal

4. Kelly Leffel Structures and Thermal
BACK-UP SLIDES
Kelly Leffel Structures and Thermal

5. Kelly Leffel Structures and Thermal
Mass – Volume 5
Kelly Leffel Structures and Thermal

6. Kelly Leffel Structures and Thermal
Volume Equations
Surface Area(SA) = pi*R*S + pi*R^2 – pi*r*s (NO TOP)
Volume(V) = 1/3 * pi * R^2 * H – 1/3 *pi*r^2
Kelly Leffel Structures and Thermal

7. Moments of Inertia (New height and cm position)
Ixx = Iyy = m/4 * (3/2 *r ^2 + 5/24 h^2) = kg – m^2
Izz = 3 *m*r^2/4 = kg – m^2
Ixy = Iyz = -3*m*r^2/8 = kg – m^2
Ixz=Izx=Iyz=Izy = -7/48 * m*r*h = kg- m^2 7
Kelly Leffel Structures and Thermal

8. Kelly Leffel Structures and Thermal
Thermal Control
MLI Blanket
Teflon, Backed outer cover cm thick
0.354 kg
Aluminized Kapton Inner Layer (7 Layers)
0.497 kg
Dacron Netting separator layer (7 Layers) kg
Aluminized Inner Cover
0.323 kg
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9. Kelly Leffel Structures and Thermal
Cryocooler
NGST MPT
1 stage P-T
1.2 W at 120 K
Power Required 40 W
Mass 8.1 kg
Kelly Leffel Structures and Thermal 9

10. Kelly Leffel Structures and Thermal
References
Lander Phase Group for Masses
Spacecraft Thermal Control Handbook Volume I and II for Thermal Control data
Kelly Leffel Structures and Thermal 10