Artist rendering of NASA's Dawn spacecraft approaching Mars. Dawn, part of NASA's Discovery Program of competitively selected missions, was launched in 2007 to orbit the large asteroid Vesta and the dwarf planet Ceres. The two bodies have very different properties from each other. By observing them both with the same set of instruments, Dawn will probe the early solar system and specify the properties of each body. http://photojournal.jpl.nasa.gov/catalog/PIA18152