Interplanetary Trajectory Design Using Multiple Flybys in the Sun-Planet Three-Body System

Abstract Planetary exploration is crucial for investigating the origin and evolution of the solar system. Despite the significant advantage in reducing launch cost offered by multiple gravity assists, numerous unique motions in the three-body system, which could provide extraordinary benefits in interplanetary transfers, are neglected due to the application of the patched-conic method and two-body problem. In this paper, a novel design method for interplanetary trajectory is proposed, leveraging the multiple flybys in the sun-planet system. First, the concept of multiple flybys in the three-body system is presented, and various types of multiple-flyby motion are found. Following the determination of trajectory patched conditions, the method for designing interplanetary trajectory is established by connecting multiple flybys in different sun-planet systems. Finally, this method is applied to design transfer trajectories for Saturn and Neptune exploration. The results indicate that, compared to multiple gravity-assist transfers based on the two-body problem, more transfer opportunities are found by the proposed method. This paper provides a new approach for planetary exploration missions in the future.