Low-Thrust Transfers to Lunar Orbits from Halo Orbits Around Lunar Libration Points L1 and L2

This study is devoted to searching for lunar orbits that are accessible during departure along an unstable invariant manifold of halo orbits around lunar libration points L-1 and L-2. The spacecraft is assumed to be equipped with a low-thrust engine. Two levels of jet acceleration from the typical range of small-size spacecraft with low-thrust engines are considered. The study consists of two parts: (1) searching for osculating lunar orbits obtained during passive motion from halo orbits and (2) stabilization of orbits by the thrust force, directed against the spacecraft velocity. Many halo-orbits were found, the descent from which along the unstable manifold makes it possible to reach polar and near-polar orbits. The problem is solved within the model of a circular, restricted three-body problem.