Trajectory Planning for Complex Shaped Spacecraft Proximity Based on Critical Safety Curve and Disturbed Fluid

Recent research on on-orbit service rarely considers the complex shapes of servicing spacecraft (chaser) and the target simultaneously, which could cause collision problems in ultraclose-range proximity. This article presents a novel trajectory planning method via critical safety curve (TPCSC). The core of the framework is the construction of collision avoidance constraints called critical safety curve (CSC) using geometrized mathematical methods. CSC has good mathematical properties and innovatively combines the complex shape and relative attitude constraints of two spacecraft. Subsequently, TPCSC proposes an improved disturbed fluid method based on CSC that can handle non-convex constraints to generate smooth approach trajectories. Finally, the framework can achieve ultraclose-range proximity between spacecraft with complex shapes under complex non-convex constraints. The simulation results indicate that the planning of TPCSC is rapid, and the formed trajectory is safe, smooth, and easy to track.

I. Introduction

On-orbit service (OOS) is essential for the space environment since it can rescue failed spacecraft or remove orbital debris, especially in the case of the widespread utility of mega-constellation [1], [2], [3]. A key aspect of OOS is to achieve ultraclose-range proximity maneuvers. The servicing spacecraft (chaser) can approach the target through proximity maneuvers under collision avoidance constraints. However, in the ultraclose range, the relative distance between the two spacecraft is comparable to their scale. Neglecting either spacecraft's slender structures (solar panels or antenna) will result in a collision. In addition, the relative attitude of the two spacecraft interacts with their complex shape, making the construction of collision avoidance constraints more difficult. There is an urgent need to address the safety problems caused by the two spacecraft's complex shapes and relative attitude during the ultra-close-range proximity.