1. AAE450 Spring 2009 1 Spinning Descent and Compressed Gas Hopper Christine Troy Assistant Project Manager Webmaster Lunar Descent Attitude Control Analysis Design Alternative Evaluation Christine Troy Attitude

2. AAE450 Spring 2009 2 Problem  Decrease mass, power, volume, cost, and/or integration complexity through design alternatives 1)Spinning lander on descent for attitude control 2)Compress gas with force of landing and release stored energy for hopping Christine Troy Attitude

3. AAE450 Spring 2009 3  Spinning Lander –Initial analysis: 1.7 kg attitude propellant savings Increased complexity, small mass margin for required structural changes, not recommended for large payloads –New mass properties: 2.2 kg attitude propellant savings Possible benefits for very small payloads  Compressed Gas Hopper –Some or all travel could be obtained from bouncing using stored descent energy –Compressed gas not recommended – highly temperature sensitive, limited velocity and acceleration inputs Commercial gas springs limited to approx. -23° to 82°C –Lunar surface temperature -153° to 107° C Christine Troy Attitude

4. AAE450 Spring 2009 4 References  Rauschenbakh, Boris, Michael Ovchinnikov, and Susan McKenna-Lawlor. Essential Spaceflight Dynamics and Magnetospherics. Dordrecht, The Netherlands: Kluwer Academic Publishers, 2003.  Wiesel, William. Spaceflight Dynamics. New York: McGraw-Hill, 1997.  Howell, Kathleen. Notes from A&AE 440. Spring 2008.  Dengel, Yunus and Michael Boles. Thermodynamics. Boston: McGraw-Hill, 2002.  Industrial Gas Springs and Dampers. Enidine Product Guide. 2007. Christine Troy Attitude