Parking a spacecraft near an asteroid pair

Gabern, F., W. S. Koon, and J. E. Marsden

Journal of Guidance, Control and Dynamics, 29, (2006), 544-553

Abstract:

This paper studies the dynamics of a spacecraft moving in the field of a binary asteroid. The asteroid pair is modeled as a rigid body and a sphere moving in a plane, while the spacecraft moves in space under the influence of the gravitational field of the asteroid pair, as well as that of the Sun. This simple model captures the coupling between rotational and translational dynamics. By assuming that the binary dynamics is in a relative equilibrium, a restricted model for the spacecraft in orbit about them is constructed that also includes the direct effect of the Sun on the spacecraft dynamics. The standard Restricted Three Body Problem (RTBP) is used as starting point for the analysis of the spacecraft motion. We investigate how the triangular points of the RTBP are modified through perturbations by taking into account two perturbations, namely that one of the primaries is no longer a point mass but is an extended rigid body, and second, taking into account the effect of orbiting the Sun. The stable zones near the modified triangular equilibrium points of the binary and a normal form of the Hamiltonian around them are used to compute stable periodic and quasi-periodic orbits for the spacecraft, which enable it to observe the asteroid pair while the binary orbits around the Sun.