This paper outlines the strategic approach to realize a human mission to an asteroid, focusing specifically on the proximity operations. The risks and challenges posed by asteroid surfaces to in-situ investigations force the proximity operations to be done by the intermediary of robotic explorers. In this architecture, a precursor is sent years in advance to a potential target asteroids. Its main goals are the characterization of the gravity field and of the surface behavior. If the target is found suitable, the manned mission then proceeds. With their main spacecraft stationed on a stable orbit around the asteroid, the astronauts are transported to the surface via a small, unpressurized spacecraft. Hovering a few meters above the surface, they deploy and command small robotic landers that perform scientific operations at the surface.

This paper discusses a mission design concept that uses high-power solar electric propulsion (SEP) to re-direct one asteroid into the path of another, generating a low-velocity impact as a means of studying solar system evolution. In order to validate existing models and gain further insight in the processes involved, a multispacecraft approach is proposed. This concept involves stationing a spacecraft at each asteroid, using them to achieve precise orbits of both asteroids, and one of the spacecraft with high-power SEP to deflect its asteroid into a low-velocity collision with the other. This study will show that it is possible to achieve asteroid collisions with a relative velocity below 10 km/s, allowing direct observations to study solar system dynamics.