Dawn is a space probe, launched by NASA in September 2007, to study objects in the asteroid belt. Dawn is currently in orbit around the dwarf planet Ceres, after visiting and orbiting the asteroid Vesta.
Dawn is the first spacecraft to:
- orbit two bodies in the Solar System
- visit Ceres or Vesta
- visit a dwarf planet (Dawn arrived at Ceres a few months before New Horizons arrived at Pluto)
The Dawn mission aims to understand more about the formation of the solar system, and to test a new method of powering spacecraft. The objects Ceres and Vesta were chosen as they are very different to each other: Ceres is icy and cold, Vesta is rocky. Scientists hope to learn about the formation of rocky planets in the Solar System, and how they differ from the icy objects. They hope to understand how a rocky object can hold water.
On its approach to Vesta, Dawn took a series of photographs of the asteroid. It entered Vesta's orbit, and discovered a series of dark spots on Vesta's surface, sites of ancient asteroid impacts. Dawn left Vesta's orbit, and over two years later the spacecraft approached Ceres. Dawn took another series of photographs, before entering the orbit of Ceres.
Once in orbit around Ceres, Dawn started to map the dwarf planet's surface. The spacecraft moved into an orbit even closer to Ceres, and various scientific instruments determined the chemical elements on its surface.
As of August 2017, NASA are still making decisions about the future of the Dawn mission. The spacecraft may fly by another asteroid, another object in the Solar System, or remain orbiting Ceres to gather more data.