Dawn was the first spacecraft to orbit both an asteroid and a dwarf planet.
NASA launched Dawn in September 2007 with an ion propulsion system that allowed it to change orbit repeatedly while using relatively little propellant. It reached the asteroid Vesta in July 2011 and orbited that protoplanet for more than a year, studying its giant impact basin, surface composition and geological history.
Dawn then departed Vesta and became the first spacecraft to orbit a second extraterrestrial body. It arrived at Ceres in March 2015, making Ceres the first dwarf planet visited by a spacecraft and the first dwarf planet to be orbited.
Dawn’s bright spots at Ceres, especially those in Occator Crater, became one of the mission’s most recognizable discoveries. Rosetta orbited a comet, while New Horizons flew past Pluto without entering orbit.