A fuel-optimal transfer orbit scheme for a retrograde GEO test monitoring satellite is developed based on the redundant propulsion capability of the rocket’s upper stage for the trans-lunar departure of manned lunar missions. This paper first introduces the redundant propulsion capability of the rocket’s upper stage for the trans-lunar departure of the lunar module and crew vehicle. Furthermore, the engineering application potential and the strategy for carrying retrograde GEO monitoring satellites are discussed. A patched design model for the lunar module and crew vehicle transfers in the co-rotating coordinate system is established, and the fuel consumption and spacecraft-separation epochs from the lunar module and crew vehicle are analyzed and compared. The simulation results show that the optimal trans-lunar orbit carrying strategy for the lunar module consumes less fuel than the optimal free-return orbit carrying strategy of the manned spacecraft. The total delta-v (mid-course and terminal delta-v values) of GEO insertion is approximately 1.773 km/s. The optimal mid-course delta-v epoch is approximately 4.36 days after trans-lunar injection.
HE et al. (Sun,) studied this question.