Design and experimental implementation of optimal spacecraft atntenna slews

Abstract

This thesis investigates the development and implementation of optimal slew trajectories for positioning a spacecraft antenna. Conventional maneuvers are developed by considering each gimbal independently. Consequently, maneuver design is simple, but may be highly sub-optimal and cause significant torques to be imposed on the spacecraft body. This work explores the impact of implementing optimal slew paths that best utilize system dynamics with the objective of increasing available customer time on communications links and enabling new missions. Accomplishing this required the development of a detailed multibody system model that can be easily tailored to any spacecraft antenna configuration. Various software suites were used to perform thorough validation and verification of the Newton-Euler formulation developed herein. The antenna model was then utilized to solve an optimal control problem for a geostationary communications satellite. The developed maneuvers not only reduce the antenana slew time, but also reduce the impact of the antenna motion on the spacecraft attitude. This reduces reliance on the spacecraft attitude control system to maintain pointing, and minimizes the impact of antenna motion on the operation of other payloads. Successful implementation of the designed maneuvers on a laboratory testbed validate the approach in a real hardware environment.