Coupled orbit-attitude dynamics of a captured asteroid during swing-bys

The rotational state and structure of minor bodies undergo major disruptions during very close encounters with massive bodies. This paper proposes the use of tidal interaction during a swing-by to modify or manipulate the spin and possibly the structure of asteroids, primarily during capture. The possibility of de-spinning, spinning-up or controlled break-up of a captured asteroid is considered. Three simple planar models are used to study the orbit-attitude interactions: the coupled dynamics of an ideal mass-point dumbbell, a simplified decoupled rigid body rotation dynamics, and a circular orbit binary. The evolution of the rotational state and structure of the asteroids is studied for the hypothetical cases of a single lunar or Earth swing-by prior to capture. The final conditions are shown to be highly dependent on the initial rotational state, the distance to the swing-by body, and, most importantly, the relative attitude of the asteroid to the local vertical at pericentre.