AbstractThe minimum-fuel orbital transfer is analyzed in the case of a launcher upper stage using a constantly thrusting engine. The thrust level is assumed to be constant and its value is optimized together with the thrust direction. A closed-loop solution for the thrust direction is derived from the extremal analysis for a planar orbital transfer. The optimal control problem reduces to two unknowns, namely the thrust level and the final time. Guessing and propagating the costates is no longer necessary and the optimal trajectory is easily found from a rough initialization. On the other hand the initial costates are assessed analytically from the initial conditions and they can be used as initial guess for transfers at different thrust levels. The method is exemplified on a launcher upper stage targeting a geostationary transfer orbit.
HighlightsThe minimum-fuel planar orbital transfer is solved in the case of an engine thrusting at constant optimized level.An analytical closed-loop solution is found for the thrust direction.The optimal trajectory is obtained without any costate propagation.Analytical expressions are obtained for the initial costates.The analytical costates provide a very good guess for transfer problems at non optimal thrust levels.
Optimal thrust level for orbit insertion
Acta Astronautica ; 136 ; 55-63
2017-02-28
9 pages
Article (Journal)
Electronic Resource
English
Optimal Thrust Level for Orbit Insertion
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