Dawn is a space probe launched by NASA in September 2007 with the mission of studying two of the three known protoplanets of the asteroid belt, Vesta and Ceres. It is currently in orbit about its second target, the dwarf planet Ceres. Dawn is the first spacecraft to orbit two extraterrestrial bodies, the first spacecraft to visit either Vesta or Ceres, and the first to visit a dwarf planet, arriving at Ceres in March 2015, a few months before New Horizons flew by Pluto in July 2015.
Dawn entered Vesta's orbit on July 16, 2011, and completed a 14-month survey mission before leaving for Ceres in late 2012. It then entered Ceres' orbit on March 6, 2015. NASA considered, but decided against, a proposal to visit a third target. On October 19, 2017, NASA announced that the mission would be extended until its hydrazine fuel runs out, possibly in the second half of 2018; afterwards, the spacecraft is expected to remain in a stable orbit around Ceres. As of August 2018, Dawn is orbiting Ceres in its final orbit, as close as 35 km (22 mi) and as far away as 4,000 km (2,500 mi).The Dawn mission is managed by NASA's Jet Propulsion Laboratory, with spacecraft components contributed by European partners from Italy, Germany, France, and the Netherlands. It is the first NASA exploratory mission to use ion propulsion, which enabled it to enter and leave the orbit of multiple celestial bodies. Previous multi-target missions using conventional drives, such as the Voyager program, were restricted to flybys.
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