Occator crater on Ceres. Composite created with data from NASA's Dawn spacecraft, showing the topography of Occater, an impact crater on the surface of Ceres. Ceres is a minor planet, the largest object in the asteroid belt, and lies between the orbits of Mars and Jupiter. Vertical data has been exaggerated by a factor of 5 to better to illustrate the crater's topography. The mysterious bright white spots within the crater may be related to a type of magnesium salt, and associated with ammonia-rich clays. Dawn was launched on 27 September 2007 on a mission to study Ceres and the asteroid Vesta, the two largest bodies in the asteroid belt. It will provide data on their composition, formation and the early history of the solar system. This three-dimensional terrain model is based on images taken during orbits at altitudes of 13, 600 kilometres and 5, 100 kilometres.