AAS 98-166

APPLICATION OF OPTIMAL PERIODIC CONTROL THEORY TO THE ORBIT REBOOST PROBLEM

K. E. Jensen, F. Fahroo, I. M. Ross - Naval Postgraduate School

Abstract

In a previous paper, it was shown that a forced Keplerian trajectory (FKT) obtained by thrust-drag cancellation is not Mayer-optimal. Application of this result to the fuel-optimal orbit maintenance problem implies that periodic reboosts must be more efficient than a thrust-drag cancellation. A linear analysis indicates that the performance of periodic Hohmann reboosts is the same as that of an FKT. To determine the optimal reboost strategy, we formulate an optimal periodic control problem. This problem is numerically solved by a spectral collocation method. Initial analysis indicates that fuel savings of at least 8% is possible for the international space station.

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