As evidenced by the Global Exploration Roadmap, international interest exists in a new era of human exploration of the solar system. Such an effort is commencing with the examination of options for maintaining a facility—at times crewed—in an orbit nearby the Moon. Thus, the key objectives in advancing colonization of interplanetary space include positioning and maintaining an inhabited facility in a long-term and relatively stable orbit in the lunar vicinity. At this time, one orbit of interest for a habitat spacecraft is a Near Rectilinear Halo Orbit (NRHO). Near rectilinear halo orbits near the Moon are members of the L1 or L2 halo orbit families and are characterized by favorable stability properties. As such, they are strong candidates for a future habitat facility in cislunar space. This type of trajectory is identified in cislunar space in terms of the Earth-Moon Circular Restricted Three-Body Problem (CR3BP). However, for arrival to and departure from the Earth-Moon region, the impact of the solar gravity generally cannot be ignored. Thus, the orbital characteristics and stability properties are examined within the context of the bicircular restricted four-body problem.
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