Final Lander Volume and Mass
10kg, 100g, Arbitrary
March 12, 2009
Lunar Descent Phase Group
1
AAE450 Spring 2009
[Ryan Nelson] [STRC]
Final Lander Dimensions and Volume (All Cases)
Height
Top Diameter
Bottom Diameter
Total Volume
10kg
100g
Arbitrary
1.1 m
1.0 m
2.0 m
1.0 m
1.0 m
2.4 m
1.3 m
1.3 m
3.6 m
1.149 m3
1.045 m3
14.326 m3
•Arbitrary Volume based on max diameter of payload fairing
•Height Scaled from 100g case
•Need for additional thrusters cause 1.1m height on 10kg
2
AAE450 Spring 2009
Final Frame Mass (All Cases)
 100g
– Mass of Frame = 11.44 kg
 10kg
– Mass of Frame = 19.97 kg
 Arbitrary
– Mass of Frame = 104.86 kg
•Arbitrary Case Scaled from 100g
•No need for added structure to support extra 2 thrusters
•Thrusters for hop have no effect on volume constraints
3
AAE450 Spring 2009
Key Drivers in Lander Frame Size
 H2O2 Tank Radius
 Main Chamber Height
– 0.53 m for 10kg
– 0.5 m for 100g
 Pressure Tank Radius
– 0.4 m 10kg
– 0.38 m for 100g
 Nozzle (Only constraint
for Leg size)
– 0.325 m both cases
– This leaves 0.275 m
ground clearance
4
– 0.438 m for 10kg
– 0.293m for 100g
– 0.3525 m into Lander for 2
added thrusters on 10kg
case
 Solar Panel
– needs 0.7854m2 area for
both cases
– Top diameter must be 1 m
 Payload Size (Only 100g)
– Approx 0.35m3 X 0.35m3 X
0.35m3
AAE450 Spring 2009
Explanation behind Lander Frame Masses
 Volume and total mass upon touchdown
drivers in overall frame mass
– Larger volume means more material and
more mass
– Larger mass on touchdown means individual
frame components must be thicker to support
larger loads
– Code from last weeks presentation used in
iterative process
5
AAE450 Spring 2009
Calculations for Thruster Angle on 10kg case
 Center of Mass code used to find line of action
for thrust
– Center of Mass found to be 0.2606 m from bottom of
Lander at Touchdown
 Chamber of thrusters oriented perpendicular to
Lander floor
– Only the nozzle is tilted to fire through CM
 5 cm between main chamber and thruster
chamber
 5.75 cm of the chamber is exposed (hangs out
of Lander floor)
6
AAE450 Spring 2009
Calculations for Thruster Angle on 10kg case
(Cont.)
 Optimal angle of
action = 32.26°
 Clearance from
bottom of Lander =
2.68 cm
7
AAE450 Spring 2009
Center of Mass Code
 Allows for easy CM calculation as individual components
of Lander change.
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AAE450 Spring 2009