VEHICLE-AND-TRAJECTORY OPTIMIZATION OF NUCLEAR ELECTRIC SPACECRAFT FOR LUNAR MISSIONS

A new combined vehicle-and-trajectory optimization problem is solved f or a low-thrust nuclear-electric-propulsion spacecraft whose motion is governed by restricted three-body-problem dynamics for the Earth-moon system, The problem involves computing the optimal spacecraft sizing parameters and trajectory design variables that result in the maximum payload for a fixed-trip-time, planar transfer from circular low Earth orbit to circular low-lunar orbit. In particular, the optimal specifi c impulse and input power are computed, The detailed vehicle- and-traj ectory optimization approach is effective in solving a complex interac tive problem that is important to both spacecraft and mission designer s. Several numerical solutions are obtained for a wide range of trip t imes,