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January 29, 2009. Preliminary Trans-Lunar Analysis. 1. Bielliptic Transfer. Two Body Problem (Point Mass Central Bodies) Coplanar transfer between Earth (200 km) and lunar (110 km) parking orbits Method of patched conics For Calculation: Use intermediate radius 1,000,000 km
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January 29, 2009 [Levi Brown] [Mission Ops] Preliminary Trans-Lunar Analysis 1
Bielliptic Transfer • Two Body Problem (Point Mass Central Bodies) • Coplanar transfer between Earth (200 km) and lunar (110 km) parking orbits • Method of patched conics • For Calculation: • Use intermediate radius 1,000,000 km • beyond the moon’s orbit Bielliptic consistently slightly larger for reasonable flight times Impulse Thrust = Hohmann [Levi Brown] [Mission Ops] 2
Low Thrust Transfer • Electric propulsion sizing analysis from • Space Propulsion Analysis and Design • Circular spiral transfer: • ΔV = ΔV2 – ΔV1 ≈ 7 km/s • Isp varied 1000-4000 seconds • Efficiency of 0.55 • Results: • Time of Flight 1-8 months • Requires 55-500 mN and 2-5 kW [Levi Brown] [Mission Ops] 3
[Levi Brown] [Mission Ops] Back-up Slides 4
Comparisons for Other Orbits [Levi Brown] [Mission Ops] 5
Comparisons for Other Orbits [Levi Brown] [Mission Ops] 6
[Levi Brown] [Mission Ops] Reference Humble , Ronald W., Henry, Gary N., Larson, Wiley J. Space Propulsion Analysis and Design. McGraw-Hill Companies, 1995, Pg 518, 619. 7