Minimizing Eclipses via Synodic Resonant Orbits with Applications to EQUULEUS and MMX

For deep-space missions that remain in the vicinity of a target body, solar eclipses might become a source of major concern due to tight thermal and power budgets. This paper presents a method for minimizing the eclipse duration of periodic trajectories in three-body systems using synodic resonant periodic orbits. Our derivations successfully capture the global eclipse structure of synodic resonant periodic orbits in terms of driving parameters such as the elongation and phase angles. Two-dimensional Eclipse maps are introduced to identify optimal orbit insertion conditions that avoid or minimize eclipse intervals. The validity and applicability of the proposed method is tested in the full-ephemeris model of the Earth-Moon and Mars-Phobos systems, respectively. As a result of these investigations, we propose new science eclipse-minimum trajectories that are under consideration for the upcoming JAXA missions EQUULEUS and MMX.