Navigation Challenges of a Kinetic Energy Asteroid Deflection Spacecraft

Abstract

*† ‡ § ** †† , A simple asteroid deflection experiment can be conducted by a small and inexpensive impactor spacecraft in cooperation with an independent asteroid rendezvous mission. The rendezvous mission would arrive at a near-Earth asteroid in advance of the impactor in order to characterize the asteroid while the impactor makes its way to the target. Then the rendezvous spacecraft would be in position to record the impact event, as well as to measure the deflection imparted as a result of the collision. This paper describes the mission concept and addresses the navigational challenges in delivering the impactor, as well as measuring the resultant deflection. I. Introduction simple and robust asteroid deflection experiment can be conducted by a relatively small and inexpensive impactor spacecraft, in close cooperation with an independent asteroid rendezvous mission. The rendezvous mission would arrive at a benign near-Earth asteroid in advance of the impactor launch in order to characterize the asteroid, acquire samples, etc., while the impactor makes its way to the target. Then the rendezvous spacecraft would be in position to record the impact event and document the post-impact scene, as well as to measure the deflection imparted as a result of the impactor’s collision with the asteroid. This concept requires that the rendezvous spacecraft already be in orbit around a candidate asteroid to take data before, during and after the impact to verify that a measurable change in the asteroid’s velocity took place and to study the dynamics of the impact itself. Such a mission would answer the critical question as to what momentum enhancement is provided by the ejected asteroidal material during the cratering process. This “blow back” momentum enhancement effect is thought to be significantly larger than the momentum provided by the impacting spacecraft itself. In addition to the obvious planetary defense aspects of such a mission, the scientific returns would be immense. Spacecraft information could be used to characterize the asteroid’s size, shape, mass, morphology, bulk density, porosity, rotation state, and composition, while an in situ study of the cratering event itself would allow insight into the asteroid’s interior structure.