Capturing an asteroid via triangular libration points

This paper develops a new asteroid capture mechanism via triangular libration points based on their stable structure and chaotic motion nearby. Different from collinear libration points, the triangular libration points are linearly stable surrounded by long-and short-period orbit families in the planar case. First, their dynamical structure is explored by the Lie series method and an analytical approximation of long-period orbits is proposed. Then, massive escaping trajectories from the parking orbits are generated by a chaotic-assisted method on the finite time Lyapunov exponent map. The trajectories from the asteroid’s natural orbit to the Earth–moon system are constructed by modified Lambert transfers. Next, the fuel consumption for all potential near-Earth asteroids is evaluated ergodically in both perihelion and aphelion cases based on their initial condition, which guides the selection of the target. Finally, it is applied to 20 asteroids, and the minimum fuel consumption (∼887.9  m/s) appears capturing asteroid 2015DU. Furthermore, a postcapture maneuver strategy based on a Poincaré section is proposed using long-period orbits to adjust the parking orbits and to satisfy the mission requirements.