Active solar eclipse avoidance on the distant retrograde orbit of the Earth-Moon system

Lighting condition is a significant concern for spacecraft because it is directly related to their power and thermal subsystems. For spacecraft moving on a Distant Retrograde Orbit (DRO) of the Earth-Moon System, the lighting condition is severe because the DRO faces frequent long-duration solar eclipses. This study proposes a solar eclipse avoidance strategy for DRO missions. First, the lighting condition on a stable nominal DRO is analyzed, which reveals that long-duration solar eclipses are inevitable and active avoidance maneuvers are essential. Then, a close-loop three-impulse maneuver strategy is developed to deviate the trajectory from the nominal DRO and avoid a single shadow region of the Earth (or the Moon). The analytical solution of the first velocity impulse required for orbit correction at an arbitrary position is derived. The optimal position of imposing the velocity impulse is obtained using a nonlinear programming-based optimization algorithm. Finally, a coordinated shadow avoidance algorithm is proposed to simultaneously avoid the shadow of the Earth and the Moon. Simulations show that the proposed strategy successfully keeps the flying trajectory outside the shadow regions in a 4-year mission time at an average annual velocity impulse cost of 46.936 m/s.