Log-linear Dynamic Inversion for Thrusting Spacecraft on SE2(3)

Abstract: We show that the dynamics of a thrusting spacecraft can be embedded in the Lie group SE2(3) in a form that is group-affine with application of a feed-forward control law. This structure implies that the configuration-tracking error evolves exactly linearly in the associated Lie algebra coordinates (log-linear dynamics), rather than arising from a local linearization of the nonlinear system. As a result, a broad class of linear analysis and synthesis tools becomes directly applicable to powered spacecraft motion on SE2(3). A simple numerical example confirms that the error predicted by the linear Lie-algebra dynamics matches the error computed from the full nonlinear system, illustrating the exact log-linear behavior. This foundational property opens a path toward rigorous tools for satellite docking, autonomous rendezvous and proximity operations, robust controller design, and convex safety certification-capabilities that are difficult to achieve with classical local linearizations such as Tschauner-Hempel/Yamanaka-Ankersen (TH/YA).