Spacecraft trajectory tracking and parameter estimation in the presence of a splitting contact binary asteroid

Abstract

Increasing interest in asteroid mining and in-situ resource utilization will lead to an increase in asteroid surface operations. The composition of asteroids is often unknown and potentially unstable, many of which are bound together predominantly by gravitational forces. Surface operations such as mining may significantly alter the asteroid’s structure or, in the case of contact binary asteroids, cause the asteroid to split. Conditions on the evolution of the contact binary system after splitting are derived. Observability issues causing inconclusive results in the previous work were addressed here by identifying an observable set of constant parameters which describes the splitting system. The coupled problem of estimating unknown parameters of a newly-formed binary system and controlling a spacecraft’s trajectory in the system’s vicinity is investigated. An indirect adaptive control scheme is utilized to simultaneously and accurately meet both objectives. Finally, a simpler control scheme, based only on 2-body dynamics is derived to show significant improvement in performance when using the proposed adaptive control scheme over using the simple 2-body controller. For larger contact binary asteroids, the adaptive control scheme has shown up to a 20% reduction in control cost over the 2-body controller.