NASA’s Dawn unmanned space probe fires up its ion propulsion system, breaking its orbit around the large asteroid Vesta. Having orbited and mapped Vesta since 2011, Dawn must now survive a nearly-three-year trip through the main asteroid belt to reach the largest body in that region, Ceres. Successful arrival at Ceres, planned for 2015, would make Dawn the first unmanned spacecraft to have orbited two bodies in the solar system.
