An optical terminal guidance and navigation strategy in the asteroid rendezvous mission

An impending demand for exploring the small bodies such as the comets and the asteroids envisioned the MUSBS-C mission to the near Earth asteroid Nereus. An autonomous guidance and navigation scheme around the asteroid is discussed in this paper. It is based primarily on the use of optical sensors. Two kinds of new strategies are presented here: One is the terminal guidance in the electric propulsion that makes the spacecraft intercept the asteroid from the prescribed direction. It will be shown that this technique can be applied to the initial phase of descent propelled by the chemical propulsion. The other one is the new navigation scheme that provides the geographical information without any use of the mapping information taking the advantage of the frozen orbital properties. Some typical numerical examples are given here. They demonstrate the discussion in the paper.