Attitude–Trajectory Optimization for Low-Detectability Spacecraft Proximity Operations With Multiple Spacecraft Observers

To address the trajectory detours and increased control effort that can arise from field-of-view (FOV) avoidance schemes in environments containing multiple third-party observing spacecraft, this paper investigates joint attitude–trajectory planning for geometry-based low-detectability proximity operations of a spacecraft with unidirectional main thrust. A coupled attitude–trajectory optimal control model with multiple constraints is established by considering a fixed forward-looking camera, a rear propulsion aperture, direction-dependent solar-array geometric blocking, and unidirectional main thrust. Compound state-triggered constraints (cSTCs) are used to describe the direction-dependent low-detectability geometric requirements activated within third-party observation FOVs, and the resulting problem is solved within a successive convexification (SCvx) framework. In the main case, all FOV-active transcription nodes of the attitude-assisted solution satisfy the prescribed direction-dependent geometric constraints. Compared with the FOV-avoidance scheme, the attitude-assisted scheme reduces the thrust impulse by 45.35% in the considered main scenario. In a scenario in which the terminal location is unavoidably inside a third-party observation FOV, the attitude-assisted formulation admits a discrete solution by adjusting the direction-dependent low-detectability geometry, illustrating the additional mission-design freedom provided by attitude assistance for the specific terminal-covered geometry considered in this study.