Orbital dynamics about a slowly rotating asteroid

Abstract

We analyze orbital stability of satellites (moonlet, spacecraft) near a slowly rotating axisymmetric asteroid. Using simple point mass models as a guide, we discover an unstable region near the equatorial plane of an indented asteroid. The existence of stable/unstable regions is confirmed numerically for a realistic “peanut” model asteroid. The stable region is found to survive small asteroidal rotation about an axis of maximum moment of inertia. A simple semi‐empirical formula is found for the orbital tilt angle as a function of asteroid rotation speed. Implications for motion about realistic asteroids are discussed.