A new low-thrust trajectory optimization tool has been developed. This method can quickly obtain minimum-time, three-dimensional Earth-orbit transfers, and can accommodate Earth-shadow effects. Two key features improve the computational speed and convergence properties of the optimization technique: (1) the use of a simple, iterative scheme for generating a good initial guess for the trajectory-shaping parameters, and (2) the use of a simplified Earth-shadow model. An iterative initial-guess generator improves a preliminary set of trajectory-shaping parameters that are based on Edelbaum's classic analytic method (and extensions to Edelbaum's original work) for optimizing quasicircular transfers. The subsequent parameter optimization problem involves a small set of free optimization variables (less than ten), and the numerical search rapidly converges to an optimal solution. Several numerical trials demonstrate the accuracy and run-time performance of the new optimization method. This preliminary analysis suggests that the new efficient optimization method would be a useful tool for mission and spacecraft designers.
展开▼
