  The growing number of noncooperative flying objects has prompted interest in
sample-return and space debris removal missions. Current solutions are both
costly and largely dependent on specific object identification and capture
methods. In this paper, a low-cost modular approach for control of a swarm
flight of small satellites in rendezvous and capture missions is proposed by
solving the optimal output regulation problem. By integrating the theories of
tracking control, adaptive optimal control, and output regulation, the optimal
control policy is designed as a feedback-feedforward controller to guarantee
the asymptotic tracking of a class of reference input generated by the leader.
The estimated state vector of the space object of interest and communication
within satellites is assumed to be available. The controller rejects the
nonvanishing disturbances injected into the follower satellite while
maintaining the closed-loop stability of the overall leader-follower system.
The simulation results under the Basilisk-ROS2 framework environment for
high-fidelity space applications with accurate spacecraft dynamics, are
compared with those from a classical linear quadratic regulator controller, and
the results reveal the efficiency and practicality of the proposed method.
