Asteroid Observation and Landing Trajectories Using Invariant Manifolds

In this paper a study of the equilibrium points of a rotating non-spherical asteroid\udis performed with special emphasis on the equilibria aligned with the longest axis of\udthe body. These equilibrium points have the same spectral behaviour as the collinear\udLagrange points of the Restricted Three Body Problem (RTBP), saddle-centres, and\udtherefore unstable and stable invariant manifolds can be computed. The invariant\udmanifolds of the equilibrium point or periodic orbits around it, which are fuel-free\udtrajectories, can approach the surface of the asteroid, orbit around it for dierent\udamounts of time, and even impact on it. This paper studies the dependence of the\udexistence of fuel-free trajectories to the surface of the asteroid from the equilibrium\udpoint on the shape and rotation rate of the body. A possible manoeuvre to orbit\udthe asteroid to observe it and later achieve vertical landing is proposed. The theory\uddeveloped is then applied to asteroid 4660 Nereus, for which an approach, observation\udphase and landing manoeuvre is designed