Abstract: In order to meet the objective requirements of landing on lunar surface at the fixed point and at the fixed time, a design method of orbit maneuvers of whole course is proposed. The phased design and joint planning of the whole-course orbit maneuvers including Earth-Moon transfer, lunar orbit insertion, lunar orbit height descent and powered descent are carried out to realize the time-fixed pinpoint lunar landing under the condition of the orbit injection deviation. The planning variables and target parameters of the three-phase orbit maneuvers with mid-course correction, lunar orbit insertion, and lunar orbit height descent are respectively constructed. According to the orbital inclination, the matching transformation relationship between the powered descent point and the landing point is established. The joint planning of the whole-course orbit maneuver strategy including mid-course correction, lunar orbit insertion, lunar orbit height descent and powered descent is designed. The time and position’s deviation of the landing point are converted into the inclination deviation and the semi-major axis deviation, and the corrections are made to the inclination of the mid-course correction’s aiming target and the semi-major axis of the lunar orbit insertion’s aiming target. The simulation examples show that with the deviation of the injection orbit, the flight orbit after mid-course correction is basically consistent with the nominal orbit and the flight orbits of the orbit height descent and powered descent are basically unchanged. The design method of the whole-course orbit maneuvers can be applied to the orbit design and control implementation of the lunar landing, lunar sampling return, and manned lunar landing missions.

Key words: Time-fixed pinpoint lunar landing, Whole-course orbit maneuvers, Mid-course correction, Lunar orbit insertion, Orbit height descent, Powered descent