Transfers between the Earth-Moon and Sun-Earth systems using manifolds and transit orbits

The L-1 and L-2 libration points have been proposed as gateways granting inexpensive access to interplanetary space. The lunar libration points, in conjunction with the collinear libration points in the Sun-Earth system, may also become primary hubs for future human activities in the Earth's neighborhood. The associated manifold tubes have been introduced by a number of researchers as the basis for design strategies to produce trajectories that shift between different systems. Intersections may ultimately be sought between many tubes from many different libration point orbits in each system; the complexity forces a new look at the computations. Individual transfers between three-body systems have been the focus of some recent investigations. This paper presents an approach to solve the general problem for transfers between the Earth-Moon system (lunar orbits and/or lunar libration point orbits) and Sun-Earth/Moon L-2 libration point orbits. The solutions are transitioned to the full ephemeris models with additional perturbations and the transfers can be determined for various lunar phases. The solution process also seeks the particular Lissajous trajectory in each system to accomplish the transfer at a low cost. Some results are presented for various types of transfer problems. (C) 2006 Elsevier Ltd. All rights reserved.