Safe and Optimal N-Spacecraft Swarm Reconfiguration in Non-Keplerian Cislunar Orbits

This paper presents a novel fuel-optimal guidance and control methodology for spacecraft swarm reconfiguration in Restricted Multi-Body Problems (RMBPs) with a guarantee of passive safety, maintaining miss distance even under abrupt loss of control authority. A new set of constraints exploits a quasi-periodic structure of RMBPs to guarantee passive safety. Particularly, this can be expressed as simple geometric constraints by solving optimal control in Local Toroidal Coordinates, which is based on a local eigenspace of a quasi-periodic motion around the corresponding periodic orbit. The proposed formulation enables a significant simplification of problem structure, which is highly applicable to large-scale swarm reconfiguration in cislunar orbits. The method is demonstrated in various models of RMBPs (Elliptical Restricted Three-Body Problem and Bi-Circular Restricted Four-Body Problem) and also validated in the full-ephemeris dynamics. By extending and generalizing well-known concepts from the two- to the three- and four-body problems, this paper lays the foundation for the practical control schemes of relative motion in cislunar space.