Active Removal of Tumbling Orbital Debris Using an Autonomous Chaser Vehicle in the Presence of Perturbations

Abstract

To address and abate the issues related to uncontrolled debris in orbit around Earth, active debris removal (ADR) is imperative. To perform ADR, a chaser satellite is used to rendezvous and capture the debris. Docking with debris is difficult as it is rotating about multiple axes; this is known as tumbling. This thesis details the development of an autonomous flight control strategy that attempts to synchronize and dock with tumbling debris in orbit to facilitate capture. The control strategy employs a model predictive control algorithm to predict the future state of the chaser and debris while simultaneously layering a separate closed-loop attitude controller to orient the chaser towards the debris. The control strategy was shown to successfully dock to debris tumbling at 2.6 deg/s with a 0% failure rate when at an initial separation of less than 25 m from the debris. The chaser was also able to reliably dock in less than 5 minutes to debris tumbling up to 4.5 deg/s when initially positioned 2.45 m from the debris. This research demonstrates that a single control scheme can potentially be used to successfully service a wide variety of candidate debris missions and docking conditions. The control strategy also demonstrates disturbance rejection, including recovery from a simulated micro-asteroid impact. The implemented algorithms were developed to integrate with a planar air-bearing testbed for future validation of the control strategy using hardware.