AAS 97-717
A DIRECT APPROACH FOR COMPUTING NEAR-OPTIMAL LOW-THRUST TRANSFERS
C.A. Kluever, S.R. Oleson - University of Missouri-Columbia
Abstract
A method for computing near-optimal, minimum-time Earth-orbit transfers for solar electric propulsion (SEP) spacecraft has been developed. A direct optimization approach is utilized to solve the optimal control problem. The thrust direction time history is parameterized by combining three external feedback control laws and the optimal thrust steering is obtained by computing the optimal weights for each feedback law. This approach is applied to long-duration orbit transfers and the effects of Earth shadowing, oblateness, and solar cell degradation are included in the simulation. Several near-optimal transfers are presented.