Orbit Transfer Trajectory Optimization With Electric Engine

In this paper, it is studied optimal coplanar orbit transfer of a satellite from a low Earth orbit to a low Earth orbit using electric propulsion system. In this case the satellite is passing through the shadow area of the Earth. During this time, supplying electric power to the satellite is going to be difficult due to the solar array which is under insufficient sun power. Henceforth, the Earth's shadow effect should be taken into account for obtaining optimal trajectory for orbit transfer. The optimization method used in this paper is indirect method under the assumption of the initially circular orbit model. And the fact of turning off the electric propulsion system in the earth shadow area mean that it is possible to ON/OFF control of electric propulsion system. Therefore, in this study, the variable thrust system is also considered with direction control of thrust vector.