Radar observations of asteroids

The type of information that can be obtained from radar observations of asteroids includes sizes, shapes, spin vectors, and such surface characteristics as the decimeter-scale morphology, topographic relief, regolith porosity, and metal concentration. This paper describes the two radar facilities active in asteroid studies (the Arecibo Observatory in Puerto Rico and the Goldstone Radar in California) and techniques used in radar observations of asteroids. Results available for main-belt and near-earth asteroids are discussed.