Technique to optimize for engine shutoff constraints in electric-propulsion trajectories

A forward-looking feedback control method that can be used to plan engine shutoff periods and therefore optimize an orbit transfer was studied. As the field of solar electric-propulsion maneuver optimization currently stands, missions are designed using various different techniques of solving for many-revolution, electric-propulsion trajectories that only allowfor eclipses to be accounted for as unplanned shutoffs. Accounting for eclipse periods as only unplanned shutoffs, however, can require a significantly longer maneuver time than if the trajectory were optimized around the eclipse periods. Doing so allows for thrusting at slightly less efficient points in each revolution, thus significantly decreasing the required maneuver time, whereas the fuel use is maintained at nearly the same value. In optimizing a GTO-to-GEO transfer around eclipse periods, a complex orbit transfer was solved using this technique while saving a significant amount of flight time compared to methods currently used to design solar electric-propulsion maneuvers.