1. AAE450 Spring 2009 Final Sizing and Trajectory Design for 100 g/10kg Payloads [Levi Brown] [Mission Ops] March 12, 2009 1

2. AAE450 Spring 2009 [Levi Brown] [Mission Ops] Final Sizing and Trajectory Determination 2 10 kg Payload LLO Payload Mass (kg) 185.0 Thrust (mN)75 mdot (mg/s)4.4 Mismatch Position (km)949 ΔV (m/s)470 Additional Propellant Mass (kg) 20.5 Results Initial Mass (kg)490.8 Cost (Million $)3.6 Time of Flight (days) 290 100 g Payload LLO Payload Mass (kg) 154.9 Thrust (mN)75 mdot (mg/s)4.8 Mismatch Position (km)6786 ΔV (m/s)382 Additional Propellant Mass (kg) 18.5 Results Initial Mass (kg)415.5 Cost (Million $)3.2 Time of Flight (days) 250 Note: Cost only includes launch, power, and propellant cost These numbers will change based on the lander freeze Wed night, but the change is expected to be small

3. AAE450 Spring 2009 [Levi Brown] [Mission Ops] 3 If we don’t match spirals, how eccentric are we? Depends on location of intersection 1.Close to Earth -- ΔV low but have not escaped Earth yet -- Spiral back to Earth 2.Close to Moon -- ΔV high -- Comparable eccentricity -- Several months to circularize Conclusion: 1. Our “matching spiral” model is the way to go 2. Better solutions with more sophisticated model -- Reduced ΔV -- Closer to Moon and not as eccentric -- Introduce coasting and variable thrust to nearly eliminate ΔV 3. System is capable of achieving mission

4. AAE450 Spring 2009 Back-up Slides [Levi Brown] [Mission Ops] 4

5. AAE450 Spring 2009 [Levi Brown] [Mission Ops] 5 Plot of Trajectory for 10 kg Payload NOTE: 100 g trajectory similar

6. AAE450 Spring 2009 [Levi Brown] [Mission Ops] 6 Plot of 10 kg Trajectory with Inertial Velocity Direction at End Point NOTE: 100 g trajectory similar

7. AAE450 Spring 2009 [Levi Brown] [Mission Ops] 7 More Notes This analysis for a 400 km LEO to a 25 km LLO 100 g: Requires 1.18 kW 10 kg: Requires 1.26 kW Initial eccentricity0.73 Time to circularize to 25 km ≈ 105 days Propellant Cost≈ 20 kg Circularization Much better than 4 years as previously estimated Spacecraft mass low in this analysis=more time Nearly identical additional propellant cost Approx. 40% increase in flight time Introduces more failure modes Less accurate model Comparison to Matching Spiral Model