Ceres is the largest asteroid in the Sol star system and is considered a dwarf planet under the revised planetary classification system. Ceres was first visited by Earth spacecraft in 2015 when the Dawn space probe surveyed both Ceres and the smaller asteroid Vesta. Ceres had long been sought out for robotic mining expeditions, however the onset of World War III halted any further asteroid missions and it was not until 2106 when another attempt was made to reach Ceres.