Asteroid de-spin and deflection strategy using a solar-sail spacecraft with reflectivity control devices

Various asteroid mitigation strategies have been proposed to avoid destructive impact events. In such a mission, the spinning motion of an asteroid can prevent a precise and effective deflection maneuver. To circumvent this problem, this study investigates a novel de-spin method using a solar sail spacecraft that is attached to the surface of an asteroid. In this approach, the solar radiation pressure torque induced by reflectivity control devices on the sail membrane is exploited to cancel out the spin rate of an asteroid without requiring fuel. In addition, once attitude control is achieved after the de-spin, the trajectory of the asteroid can be deflected by leveraging the solar radiation pressure force acting on the sail attached to the asteroid. This paper constructs general theories on the proposed asteroid de-spin and deflection methods and provides evidence that this novel strategy would be a feasible option for mitigating small and slow-spinning asteroids.