Abstract: Continuous electric thrust control strategy is studied for orbit transfer from GTO to GEO. The optimization of orbit transfer is simplified to twostage strategy in view of the onboard computing ability, and the thrust direction is fixed during each stage. Meanwhile, the space environmental influences are analyzed since the electricthrustbased orbit transfer lasts longer than chemical thrust maneuver. The transit from Earths ionosphere and radiation belts is investigated. Finally, to reduce the influences of Earths ionosphere and radiation belts, the feasibility of using the orbit of which the apogee is higher than that of the normal GTO orbit as the initial orbit is discussed.

Key words: electric propulsion, lowthrust transfer, Earths ionosphere, Earths radiation belts