As a Discovery Program mission, Dawn uses tried and true technologies with inventive applications to meet mission objectives both creatively and cost efficiently. The Dawn spacecraft combines innovative state-of-the-art technologies pioneered by other recent missions with off-the-shelf components and, in some cases, spare parts and instrumentation left over from previous missions.
With its wide solar arrays extended, Dawn is about as long as a tractor-trailer at 65 feet (19.7 meters). The ion thruster is powered by large solar panels. The power ionizes the fuel (Xenon) and then accelerates it with an electric field between two grids. Electrons are injected into the beam after acceleration to maintain a neutral plasma.
Dawn Baseline Interplanetary Trajectory
The thin solid lines represent the orbits of Earth, Mars, Vesta, and Ceres. The duration of the coast periods during interplanetary cruise are exaggerated in this depiction. In addition, thrusting at Vesta and Ceres is not shown. The dates on the time plot reflect the Pacific time zone. Dawn will remain in orbit around Ceres at the end of its primary mission.