Soft Capture of Tumbling Spacecraft

The soft-capture maneuver exhibits four phases: 1. The chaser (beige) approaches the target (pink) while maintaining its line of sight. 2. Impulsive burns help avoid collision with the client (thrust vector in red). 3. Corrective burns align the capture end-effector with the target capture frame. 4. the chaser is within the capture ball and turns on its capture end-effector.

ArXiv paper: ArXiv

ISpaRo presentation slides (24/06/2024): slides

Abstract: We present a fast trajectory optimization algorithm for the soft capture of uncooperative tumbling space objects. Our algorithm generates safe, dynamically feasible, and minimum-fuel trajectories for a six-degree-of-freedom servicing spacecraft to achieve soft capture (near-zero relative velocity at contact) between predefined locations on the servicer spacecraft and target body. We solve a convex problem by enforcing a convex relaxation of the field-of-view constraint, followed by a sequential convex program correcting the trajectory for collision avoidance. The optimization problems can be solved with a standard second-order cone programming solver, making the algorithm both fast and practical for implementation in flight software. We demonstrate the performance and robustness of our algorithm in simulation over a range of object tumble rates up to 10 °/s.

8 samples of generated soft capture trajectories with different initial relative distance and tumble rate (x20 video acceleration)

Presentation at the International Conference on Space Robotics 2024

References

2024