The Delta II rocket stands ready for launch following rollback of the mobile service tower on Launch Pad 17B at Cape Canaveral Air Force Station.

The Delta II rocket stands ready for launch following rollback of the mobile service tower, or gantry, on Launch Pad 17B at Cape Canaveral Air Force Station. Starting with a boost from this higher thrust version of the Delta II rocket, the Dawn spacecraft will study the asteroid Vesta and dwarf planet Ceres, celestial bodies believed to have accreted early in the history of the solar system. To carry out its scientific mission during its nearly decade-long mission, Dawn will carry a visible camera, a visible and infrared mapping spectrometer, and a gamma ray and neutron spectrometer, whose data will be used in combination to characterize these bodies. In addition to the three instruments, radiometric and optical navigation data will provide data relating to the gravity field, and thus, bulk properties and internal structure of the two bodies. Data returned from the Dawn spacecraft could provide opportunities for significant breakthroughs in our knowledge of how the solar system formed. Launch is targeted for Sept. 27 during a window that extends from 7:20 to 7:49 a.m. EDT. Photo credit: NASA/Kim Shiflett