Dawn was launched on September 2007, to study two asteroids, Vesta and Ceres. The mission reached Vesta in 2011 where it stayed for 1 year. Dawn is now headed to Ceres, thet will be reached in 2015. Dawn’s goal is to characterize the conditions and processes of the solar system’s earliest epoch by investigating in detail these 2 asteroids, two of the largest protoplanets remaining intact since their formations.
By observing both minor planets with the same set of instruments, Dawn will provide new answers to questions about the formation and evolution of the early solar system. Dawn will be the first purely scientific mission to be powered by ion propulsion, an advanced technology successfully demonstrated by NASA’s Deep Space 1 mission. The use of solar electric ion thrusters will enable Dawn to orbit both asteroids in one mission, a feat that has not been attempted before.