AAS 95-309

Trajectory Optimization for Solar Electric Propulsion Missions to GEO Considering the Radiation and Shadow Environments

T. Miller, McDonnell Douglas Aerospace, Huntington Beach, CA

Abstract

The trajectory followed by an Electric Orbital Transfer Vehicle (EOTV) can be long, complex, and subject to many environmental effects such as solar occultation (shadow), significant radiation doses, earth oblateness, atmospheric drag, gravity gradient torques, solar pressure, etc. EOTV trip time performance is a function of the power and propulsion system performance, and the time spent in shadow and radiation belts which vary with launch date and launch time of day. An expert system with nonlinear optimization was used to enable rapid calls to a trajectory code while varying the launch window parameters. Results illustrate how these factors affect the shadow time and shadow history of an EOTV mission. The combined effects of shadow and radiation on EOTV trip time performance are shown to illustrate that proper analysis requires both considerations in optimal EOTV mission design.