Optimizing Low-Thrust and Gravity Assist Maneuvers to Design Interplanetary Trajectories

摘要

In this paper a direct method based on a transcription by finite elements intime has been used to design optimal interplanetary trajectories, exploiting acombination of gravity assist maneuvers and low-thrust propulsion. A multiphaseparametric approach has been used to introduce swing-bys, treated as coastphases between two thrusted or coasting trajectory arcs. Gravity maneuvers areat first modeled with a linked-conic approximation and then introduced througha full three-dimensional propagation including perturbations by the Sun. Themethod is successfully applied to the design of a mission to planet Mercury,for which different options corresponding to different sequences of gravitymaneuvers or launch opportunities are presented.