Design and optimization of trajectory to Near-Earth asteroid for sample return mission using gravity assists

As one of the potential candidates of the Asteroid Exploration Mission to be launched around 2010, the feasible mission scenario is investigated. The emphasis is put on the design and optimization of preliminary interplanetary transfer trajectory for the mission in this paper. According to the science goals and constraints of the mission, the 1943 Anteros was selected as the candidate. Gravity-assist technique was used for the rendezvous and sample return mission in order to reduce the total velocity increments and launch energy. Through analyzing the transfer trajectory with Earth gravity-assist, another two opportunities are found, which will fly by the 16490 asteroid and 11300 asteroid. Using the evolutionary algorithm combing the genetic algorithm with niching method, a new profile with multiple flybys is calculated and optimized. Some key parameters of the orbit are analyzed based on the optimized trajectory, which would have a direct impact on the design of other spacecraft subsystem, such as communication subsystem, power subsystem and thermal control subsystem.