Dawn (spacecraft) - Objectives

Objectives

The Dawn mission's goal is to characterize the conditions and processes of the Solar System's earliest eon by investigating in detail two of the largest protoplanets remaining intact since their formation. The primary question that the mission addresses is the role of size and water in determining the evolution of the planets. Ceres and Vesta are highly suitable bodies with which to address this question, as they are the most massive of the protoplanets. Ceres is geologically very primitive and icy, while Vesta is evolved and rocky. Their contrasting characteristics are thought to have resulted from them forming in two different regions of the early Solar System.

There are three principal scientific drivers for the mission. Firstly, the Dawn mission can capture the earliest moments in the origin of the Solar System, enabling us to understand the conditions under which these objects formed. Secondly, Dawn determines the nature of the building blocks from which the terrestrial planets formed, improving our understanding of this formation. Finally, it contrasts the formation and evolution of two small planets that followed very different evolutionary paths, so that we can understand what controls that evolution.

An extended mission following the completion of the Ceres study is also possible, although unlikely, as greater scientific returns may be attained by spending more time at Vesta and Ceres. Although 2 Pallas would have been a feasible extended target for the originally scheduled launch date, launch delays have meant that this may no longer be the case. Fuel was not specifically allocated to break orbit from Ceres, so doing this depends upon the details of the flight to Ceres.