DESIGN AND FLIGHT IMPLEMENTATION OF OPERATIONALLY RELEVANT TIME-OPTIMAL SPACECRAFT MANEUVERS

This paper presents the flight implementation of an operationally relevant time-optimal maneuver experiment on the TRACE spacecraft. The objective is to demonstrate time-optimal maneuvering capabilities within the context of a typical operational scenario, such as scientific data collection, in which a spacecraft is required slew to various orientations in succession. The time-optimal maneuvers are designed by constructing an appropriate optimal control problem formulation based on a detailed model of the reaction wheel spacecraft dynamics. The high-dimensional optimization model includes practical constraints on the spacecraft performance including the nonlinear reaction wheel torque-momentum envelope and is solved using the Legendre pseudospectral method. The flight results demonstrate that time-optimal maneuvers can be designed and predictably executed within the specified limits. Moreover, the results of the flight experiment show clearly that the application of Legendre pseudospectral method for time-optimal maneuver design can extend the capabilities of the spacecraft over a wide envelope without the need to reconfigure or otherwise modify the existing spacecraft attitude control system.