Efficient Invariant-Manifold, Low-Thrust Planar Trajectories to the Moon ?

Two-impulse trajectories as well as mixed invariant-manifold and low-thrust efficient transfers to the Moon are discussed. Exterior trajectories executing ballistic lunar capture are formalized through the definition of special attainable sets. The coupled restricted threebody problems approximation is used to design appropriate first guesses for the subsequent optimization. The introduction of the Moon-perturbed Sun-Earth restricted three-body problem allows to formalize the idea of ballistic escape from the Earth and to take explicitly advantage of lunar fly-by. Then, accurate first guess solutions are optimized, through a direct method approach and multiple shooting technique.