Abstract: A method for designing a lunar return orbit based on the Lambert problem is proposed according to the limitation of the traditional orbit design method. An orbital dynamic model is presented in three-dimensional space using new constrained parameters. The characteristics of the lunar return orbits based on this model are well studied. A function construction method is presented to deal with the optimal design with constraint conditions and an effective objective function is proposed. The orbital parameters of a certain circumlunar spacecraft are used as the initial values to design the return orbit. The results verify the effectiveness of the proposed return orbit design method and function construction method.

Key words: Circumlunar spacecraft, Return trajectory, Characteristic analysis, Function construction method