AAS 97-659
SIMULTANEOUS CONTROL OF ORBIT AND ATTITUDE MANEUVERS FOR THE GRO SATELLITE
B.A. AL-Bassam, D.J. Mook, and T. Singh - State University of New York at Buffalo
Abstract
This paper addresses the simultaneous control of both orbit and attitude dynamics for the Gamma Ray Observatory (GRO) satellite. GRO is at Low Earth Orbit (LEO) and due to atmospheric drag, it requires boosting when the altitude reaches a certain minimum value. This maneuver has to be performed in minimum time so that the operational life of the satellite is increased. Meanwhile, the onboard instruments measuring the gamma ray incident on earth has to be aligned in a certain configuration during the boosting maneuver. This problem is an application of optimal control with the objective of minimizing the maneuver time subject to the state dynamics, boundary conditions and state and control constraints. The necessary conditions of optimality is presented that results in defining a multi-point boundary value problem, which is solved using the multiple shooting technique.