Cost Comparison of Higher Parking Orbit Scale up for Arbitrary Payload

1. February 26, 2009 [Levi Brown] [Mission Ops] Cost Comparison of Higher Parking Orbit Scale up for Arbitrary Payload 1

2. Raising Departure Orbit • 1. Depart from higher circular parking orbit • Decrease lunar transfer/Increase launch • 2. Determine total cost effects • Limitations in launch vehicle capability • 3. Investigate eccentric orbits • Create curve of launch vehicle performance with orbit energy • 4. Determine mass and power for varying altitudes • Use sizing code from propulsion • 5. Best fit curve relationships • 6. Cost with varying orbit energy • Result: • Launch from lowest altitude (400 km) • Use longest time of flight (1 year) [Levi Brown] [Mission Ops] 2

3. Scale Up for Arbitrary Payload Assume OTV is deliverable mass to 400 km for that launch vehicle Sized OTV using same code as previously Determined Power required, payload mass to lunar orbit (LLO) and relative cost to LLO • Note: Assumed used same thruster as for the small payload • Looking into higher thrust and more efficient engines Result: Minimize relative cost by minimizing relative cost to LEO [Levi Brown] [Mission Ops] 3

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

5. Initial Analysis Results Using a circular departure orbit Note: Analysis performed for a mass flow rate of 7.1 mg/s and 150 day time of flight This analysis was performed prior to the change of using a minimum Parking orbit of 400 km [Levi Brown] [Mission Ops] 5

6. Dnepr Launch Vehicle Capability Eccentric Orbit Energy Levels Note: Periapsis is at an altitude of 400 km [Levi Brown] [Mission Ops] 6

7. Launch Vehicle Capability Curve [Levi Brown] [Mission Ops] 7

8. Sizing Results Note: This analysis was performed using previous payload mass of 320 kg [Levi Brown] [Mission Ops] 8

9. Initial OTV Mass with Varied Orbit Energy mdot=5.6 mg/s [Levi Brown] [Mission Ops] 9

10. Power Required with Varied Orbit Energy mdot=5.6 mg/s [Levi Brown] [Mission Ops] 10

11. Cost Model ms/c = spacecraft mass required to reach LLO CLaunch Vehicle = Total cost of launch vehicle (LV) mLV Capability = mass LV can put into orbit Ps/c = power required to reach LLO Prate = $1000/Watt Mprop= propellant mass required to reach LLO Xerate = Cost of Xe ($1200/kg) [Levi Brown] [Mission Ops] 11

12. Falcon 9 Total Cost for Varying Apoapsis 196 and 351 Day TOF [Levi Brown] [Mission Ops] 12

13. Confirmation of Results Lowest cost at 400 km Orbit and 351 days [Levi Brown] [Mission Ops] 13

14. Scale up for Arbitrary Payload Results [Levi Brown] [Mission Ops] 14

15. More Notes Increasing to 15000 km circular orbit saved 50 kg and 1.5 kW It was hoped that using a larger launch vehicle with higher capability would decrease overall cost. The cost/kg would only increase slightly, but it would allow a significant decrease in power costs. 1 Year TOF: 10000 km depart vs 400 km saved approximately 1 kW 196 days TOF: 10000 km depart vs 400 km saved approximately 3 kW For this reason, the minimum total cost for shorter TOF occurred at a median altitude of Around 4000 km vs the minimum total for longer TOF occurred at low altitudes However the increase in power to have the shorter TOF still outweighs the savings So the minimum cost still occurs at long TOF with at low altitudes [Levi Brown] [Mission Ops] 15