Identifying cislunar transport barriers with Keplerian maps

Chaotic trajectories are often overlooked in the study of cislunar motion due to their ergodic behaviour. However, their long-term evolution is restricted by dynamical barriers. These riers correspond to quasi-periodic trajectories that partition neighbourhoods of the cislunar environment. We rapidly compute invariant curves associated with these quasi-periodic trajectories using semi-analytical approximations of a planar circular restricted three-body problem (PCR3BP) periapsis map, yielding interior and exterior region Keplerian maps. For a range of energies corresponding to the opening of the L₁ L 1 and L₂ L 2 gateways, we identify barriers that prevent transport from the exterior region to the near-Earth regime. For lower energies, we also find barriers inhibiting transport from beyond cislunar space into the Earth–Moon system. These barriers are validated with numerical integration in the Earth-Moon PCR3BP.