Abstract: Aiming at the mission of Lunar south pole exploration, a launch window searching method of three stages is proposed, taking illumination conditions, the status quo of Chinese ground based TT&C systems and the constraint conditions of Earth reentry process into consideration. A return trajectory is calculated by an improved multiconic method, which combines the lunar oblateness correction in trajectories propagation. Furthermore, return trajectory simulations from Lunar south pole are carried out based on an assumed site in Shackleton rim in 2020. Results show that this launch window searching method is effective and accurate. Additionally, the improved multiconic method can reduce the terminal boundary errors effectively.

Key words: lunar south pole region； MoonEarth trajectory； launch window； lunar antipode, improved multiconic method