Exploring the asteroid belt with ion propulsion: Dawn mission history, status and plans

In this report, we describe the journey Dawn has taken in the recent past, its present status, and its future mission. The overall objective of Dawn is to explore backward in time via its observations of the primitive bodies, Vesta and Ceres. Thus Dawn embarks on three journeys. The first is its tumultuous temporal terrestrial trek during development. The second is its soon-to-be voyage in space to 4 Vesta, the second most massive asteroid in the main belt, and to 1 Ceres, the most massive. The third is its journey backward in time to infer the conditions as the solar system was formed. Finally, we discuss how it is possible to go back even further in time, beyond the horizon of the Dawn mission to obtain “pre Dawn” observations at 10 Hygiea, the fourth most massive asteroid, and one more primitive than Vesta and Ceres.