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February 5, 2009. Low Thrust Spiral Transfer Maneuvers and Analysis. 1. TLI and Lunar Capture Scenarios. Delta V breakdown for EP system Spiral transfer from 200 km Earth parking orbit to edge of moon’s sphere of influence (~66,000 km from moon – L1)
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February 5, 2009 [Andrew Damon] [Mission Ops] Low Thrust Spiral Transfer Maneuvers and Analysis 1
TLI and Lunar Capture Scenarios • Delta V breakdown for EP system • Spiral transfer from 200 km Earth parking orbit to edge of moon’s sphere of influence (~66,000 km from moon – L1) • ΔV1 = 6.70 km/s to L1 (Lagrange point 1) • Spiral Transfer from L1 to 110 km lunar orbit • ΔV2 = 0.50 km/s = 500 m/s • ΔVtot = 7.2 km/s • Compare to: ΔV2 for impulsive maneuver to put periapsis at 110 km lunar orbit, with apoapsis near L1 • ΔV2 = 1.10 km/s • ΔVtot = 7.8 km/s [Andrew Damon] [Mission Ops] 2
Higher Precision Spiral Model [Andrew Damon] [Mission Ops] Based on: • Herman and Conway: “Optimal, Low-Thrust, Earth–Moon Orbit Transfer” • Constant thrust accelerations on the order of 10-4 g • Time of flights on the order of 30 days • Our thrust half of this value, at most • Time of flights on the order of 2+ months • Equations of motion based on modifedKeplerian elements • Perturbing accelerations accounted for, from Earth, Moon, s/c thrust • Will give more accurate trajectory and time of flight data 3