Design of transfers from Earth-Moon L 1/L2 libration point orbits to a destination object

Kakoi, Masaki Ph.D., Purdue University, May 2015. Design of Transfers from EarthMoon L1/L2 Libration Point Orbits to a Destination Object. Major Professor: Kathleen C. Howell. Within the context of both manned and robotic spaceflight activities, orbits near the Earth-Moon L1 and L2 libration points could support lunar surface operations and serve as staging areas for future missions to near-Earth asteroids as well as Mars. In fact, an Earth-Moon L2 libration point orbit has been proposed as a potential hub for excursions to Mars as well as activities in support of planetary exploration. Yet, the dynamical environment within the Earth-Moon system is complex and, consequently, trajectory design in the vicinity of Earth-Moon L1 and L2 is nontrivial. Routine transfers between an Earth-Moon L1/L2 facility and Mars also requires design strategies to deliver trajectory arcs that are characterized by a coupling between different multibody gravitational environments across two-, threeand four body systems. This investigation employs an approach to solve the general problem for transfers from the Earth-Moon libration point orbits to a destination object. Mars, Jupiter, and a near-Earth asteroid (2006RH120) are incorporated as sample destination objects, and general trajectory design procedures for multiple transfer scenarios including manifold and non-manifold options are developed by utilizing simplified models based on the knowledge of the circular restricted three-body problem. Then, the solutions are transitioned to higher-fidelity models; results for multiple departure/arrival scenarios are compared.