“…Heuristic or meta-heuristic approaches are proposed for this high level transfer sequence optimization, such as exhaustive search [8], [16], [19], branch and bound [9], [13], [20], [25], Ant Colony Algorithm (ACO) [18], [26], Genetic Algorithm (GA) [2], [10], [11], [15] and heuristic greedy method [12], [14], [27]. However, for future autonomous spacecraft, the planning will be an action choosing procedure, which can produce the best actions constantly, and keep the exploring ability as well.…”