Joint Optimization of Control and Main Trajectory and Design Parameters of an Interplanetary Spacecraft with an Electric Propulsion System

Abstract

The problem of joint optimization of thrust vector control programs and main trajectory and design parameters of an interplanetary spacecraft with an electric propulsion system (EPS) is studied. The purpose of optimization is maximizing the useful spacecraft mass. For mathematical models of a controlled-in-thrust and single-mode EPS with a constant exhaust velocity and for a fixed duration of transfer over a heliocentric trajectory, the necessary conditions are obtained for joint optimality of: (a) thrust vector control, (b) departure hyperbolic velocity excess vector, (c) departure date, (d) EPS specific impulse, (e) maximum EPS power, and (f) maximum power of spacecraft’s power supply system. It is shown that, for some problems of practical interest, the optimum value of EPS thrust is equal to its minimum permissible value. The results can be of interest at the early stages of designing an interplanetary spacecraft with EPS and for justifying the choice of main parameters of developed electric propulsion thrusters.