Design of Round Trip Trajectories to Lunar L1

In this paper design of transfer trajectory from Earth park orbit to a halo orbitaround L1 of Earth-Moon system and return trajectory from halo orbit to the Earth areinvestigated. Since satisfying constraints and boundary conditions at the end of trajectoryis an important point in trajectory design, we deal with a two point boundary valueproblem. Considered constraints in this paper include height, orthogonality of positionand velocity vectors for reducing required Del-V for orbital transfer and flight pathangle. Due to complex dynamics of three body problem and also in order to satisfyingthese constraints and suitable trajectory design, the multiple shooting methods based ondifferential correction is used.