Spacecraft motion about binary asteroids

Current estimates are that over 10% of of near-Earth asteroids may be binary asteroids. Thus, spacecraft motion about asteroid binaries is an extremely relevant topic for future missions to near-Earth asteroids. It is also an interesting topic from a more academic point of view, as the binary environment integrates 4 classical problems of astrodynamics: the Hill problem, the restricted 3-body problem, the non-spherical orbiter problem, and the full 2-body problem. The goal of this paper is to properly define the dynamical environment about a binary asteroid in terms of these basic model problems, and to review known results that relate to this system. To this end, some specific results are given on the effect of solar gravitational perturbations on the stability of the L-4,L-5 libration points in the restricted 3-body problem. Additionally, a brief summary of the dynamical properties of some known binaries are given.