Solar sail trajectory optimization for earth-mars mission

Solar sailing's applications have long been taken into account for a diverse range of space vehicles' future mission. Trajectory optimization has been a focus of development activities as with other forms of low-thrust propulsion. This paper designs optimal trajectories for solar sail's interplanetary circle-to-circle transfer mission. It can be considered as a minimum time control problem. In order to reduce the overall flight time, a piecewise constant steering law is designed to investigate the performance by utilizing the direct shooting method. Through discretizing the control variable with constant values on different time segments, this optimal control problem is approximated into the nonlinear programming (NLP) problem which is solved by the successive quadratic programming (SQP) method. Finally, the numerical results are verified for this method's feasibility and optimality.