1. AAE450 Spring 2009 1 Attitude Control – Arbitrary Payload Christine Troy Assistant Project Manager Webmaster Lunar Descent Attitude Control Analysis Design Alternative Evaluation Arbitrary Payload Integration Manager Christine Troy Attitude

2. AAE450 Spring 2009 2 Problem  Size of attitude control system increases with increased mass in low lunar orbit (LLO)  Previous analysis simply assumed linear scale up of mass from 10 kg case  More detailed analysis required –Number of thrusters to counteract thrust offset –Mass and cost of thrusters –Mass and cost of required propellant  Analysis showed 14N H2O2 thrusters used in 10 kg case unsuitable for arbitrary payload (44-1500 thrusters required) Christine Troy Attitude

3. AAE450 Spring 2009 3  Recommendation: Use 355 N H2O2 thrusters for attitude control on arbitrary payload regardless of launch vehicle (4-60 thrusters required)  Allocate 2% of wet lander mass for attitude control for arbitrary payload Christine Troy Attitude Launch Vehicle Total Attitude Control Mass (kg) Cost (Thousand $) Attitude Prop Mass (kg) Dnepr444841 Falcon 913297125 Falcon 9H370190356 Ares V15967301541

4. AAE450 Spring 2009 4 Christine Troy Attitude

5. AAE450 Spring 2009 5 Christine Troy Attitude

6. AAE450 Spring 2009 6 Christine Troy Attitude Launch Vehicle Attitude Control Mass (kg) Cost (Thousand $) Number Thrusters Dnepr50 49 44 530 400 48 44 4 Falcon 9150 138 132 1500 800 97 124 8 Falcon 9H425 365 370 4200 1200 190 352 12 16 Ares V1837 1581 1596 18000 5200 730 1516 52 60 - First number in each cell is when 14N H2O2 thrusters are used. - Second number in each cell is when 400N hydrazine thrusters are used. - Third number in each cell is when 355N H2O2 thrusters are used.

7. AAE450 Spring 2009 7 References  Rauschenbakh, Boris, Michael Ovchinnikov, and Susan McKenna- Lawlor. Essential Spaceflight Dynamics and Magnetospherics. Dordrecht, The Netherlands: Kluwer Academic Publishers, 2003.  Monopropellant Hydrazine Thrusters. Astrium Space Propulsion. 21 Jan 2009. http://cs.astrium.eads.net/sp/SpacecraftPropulsion/MonopropellantT hrusters.html  Hydrazine. Astronautix. 4 March 2009. http://www.astronautix.com/props/hydazine.htm  Propellant Grade Hydrogen Peroxide. Peroxide Propulsion. 4 March 2009. http://www.peroxidepropulsion.com/hydrogen-peroxide.php  H202 Monoprop Thruster. General Kinetics, Inc. 4 March 2009. http://www.gkllc.com/products/Rocket_Engine_Catalog_mono-prop- 2004.pdf Christine Troy Attitude