Path-constrained optimal 6-DOF motion for multi-agent in-space servicing and assembly

This paper presents a novel approach to compute fuel-optimal, six-degree-of-freedom, rotational–translational maneuvers for multi-agent proximity operations adhering to path inequality constraints utilizing indirect optimization methods. The anti-collision path inequality constraints are embedded as hard constraints within the optimal control formulation, thus guaranteeing local fuel-optimality for maneuvering the system of agents. The methodology is applicable to in-space servicing and assembly (ISA) scenarios, where teams of small servicing spacecraft are required to shuttle components between a service and client spacecraft in close proximity. Simulations are performed using the Clohessy–Wiltshire dynamical model, considering different numbers of agents and various mission scenarios. The methodology developed in this paper is adaptable to a wide range of dynamical models and orbital regimes, making it a valuable framework for future ISA missions. • Indirect methods are applied to 6-DOF multi-agent trajectory optimization. • Coupled translational and rotational dynamics enable full 6-DOF coordination. • Path inequality constraints are enforced without problem size inflation. • Applicability shown across in-space servicing and assembly scenarios.