Solar sail spacecraft trajectory optimization based on improved imperialist competitive algorithm

In this paper we discuss the minimum-time orbit transfers of solar sail spacecraft for Mercury sample return missions using solar radiation pressure. In order to find the minimum-time trajectory transfers, the optimal pitch angle of the solar sail has to be determined. We transform the optimal control problem to parameterized nonlinear programming problem by using the direct shooting method. Then, the improved imperialist competitive algorithm is used to optimize the pitch angle and the transfer time of the solar sail. Thus, we can obtain the optimal transfer trajectory according to the sail´s orbital dynamics. Furthermore, transfers from the Earth orbit to Mercury and from the Mercury orbit to Earth of the solar sail is simulated, the results show that it meets the orbit terminal constraints well and the results in this paper are better than the existing results.