Analytical Maneuver Library for Remote Inspection with an Underactuated Spacecraft

This paper presents an analytical library for maneuvering of an underactuated spacecraft around a central target with application to remote inspection. Free-flying small spacecraft are an attractive option for in situ remote inspection but require maneuvering strategies that are computationally simple, such that they can be implemented on a small spacecraft computer, while still allowing for constraints like plume impingement and underactuation to be included. An analytical maneuver library provides a suboptimal solution but can be computed without the need for numerical optimization. In addition, the low fuel cost of maneuvers means that the degree of suboptimality of the analytical maneuvers is marginal. To develop the library, forced circular motion is used in order to place the spacecraft in a controllable state such that external disturbances can be rejected. From there, trajectories can be designed in order to manipulate the circular motion and accomplish maneuvers such as joining the circular motion from rest or changing the circle's radius. Conditions under which plume impingement is guaranteed to be avoided are developed, and applications of the maneuver library to point-to-point maneuvering and landing on/docking to a rotating target are shown.