AAE450 Spring 2009 [Andrew Damon] [Mission Ops]

Low Thrust Spiral Transfer Maneuvers and Analysis

February 5, 2009

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AAE450 Spring 2009[Andrew Damon]

[Mission Ops]

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

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AAE450 Spring 2009

Higher Precision Spiral Model

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 modifed Keplerian elements Perturbing accelerations accounted for, from Earth, Moon, s/c

thrust Will give more accurate trajectory and time of flight data

[Andrew Damon] [Mission Ops]3