Study of Iterative Guidance Mode for Lunar Ascent

Lunar ascent guidance is one of the key points for future lunar sample return and manned missions. This paper discusses the practicability of using iterative guidance mode for lunar ascent. The lunar ascent in this paper begins with a vertical rise followed by a single axis rotation and then a guided phase. The three-dimensional equations of motion for lunar ascent are derived over a flat moon with a uniform gravity field to extract the optimal control problem. Then the iterative guidance mode is deduced and extended for ascent over a spherical moon. Simulation results show that this guidance scheme satisfies all the final conditions with high accuracy. It is a feasible and effective guidance law for lunar ascent which merits consideration for actual application.