Optimum Trajectory for Low-thrust Multiple Trojan Asteroids Flybys

It is known that there is an asteroid family around L4 or L5 Lagrange point of the Sun-Jupiter system, and it is called the Trojan asteroid family. As one of outer planet exploration mission, a plan to explore the Trojan asteroids using Jupiter swing-by is considered. Based on this mission, this paper discusses multiple flybys trajectory for Trojan asteroids exploration. A trajectory optimization of Trojan asteroids exploration using multiple flybys depends largely on objects of exploration. For this reason, the stage of choosing the candidates of exploration is important, and it is indispensable to choose most qualified candidate for the mission. As the first step, this paper proposes the flyby sequence search strategy which uses a ballistic orbit, and using these results, the multiple flybys trajectory to Trojan asteroids by impulsive velocity change is designed. Next, this paper considers an optimization of multiple slow-flybys trajectory of the spacecraft which uses low thrust propulsion. Furthermore feasibility of the sequence of main-belt asteroid flyby on the way to Trojan asteroid was studied.