As NASA’s Dawn spacecraft nears its March 6th rendezvous with Ceres, it continues to send up-close images of the dwarf planet. These show mysterious bright spots, not visible from earth, which might be frozen lakes or ice volcanoes. Two bright spots are now visible in the latest images, taken from 29,000 miles away. They both appear to be centered in the same large crater.
Ceres is the largest object in the asteroid belt between Mars and Jupiter. Scientists believe that one-third of Ceres could be made up of water, and that it might contain more fresh water than the earth. Ceres has a thin atmosphere, and might also possess polar ice caps like the earth.
In addition, Ceres has sub-surface oceans, and the ice volcanoes could be due to eruptions of ice and other frozen matter. Dawn will soon take up orbit around Ceres, where it will stay for 16 months. Back in 2011 and 2012, the spacecraft first visited Vesta, the second largest object in the asteroid belt. Vesta, like Ceres and Pluto, is classified as a dwarf planet.
The Dawn mission is named for its goal of finding out more about the origins of the solar system through its visits to Vesta and Ceres, the two largest protoplanets that have remained whole and intact since their formation. Their very different histories reflect the processes at work in the first few million years of the evolution of the solar system.
The two most important factors the Dawn mission will consider are the role of size and the presence or absence of water in the processes of planet formation. It will investigate the conditions as well as the building blocks of planetary formation. Unlike Ceres, which is a water world, Vesta is dry and rocky. Vesta resembles the rocky inner planets of the solar system, while Ceres is similar to the icy outer worlds.
Dawn uses revolutionary ion propulsion technology for greater maneuverability as it moves through the asteroid belt, from orbiting Vesta to Ceres. It has two solar panels that provide energy for its acceleration system.