The Dawn spacecraft is ready for its mission to the asteroid belt. The $344 million Dawn will be the first mission to explore Ceres and Vesta, the first and third largest asteroids in the solar system (though Ceres is now touted as a dwarf planet); the first mission to orbit two bodies, arriving at Vesta in 2011 and Ceres in 2015; and the first use of an ion engine on a planetary mission. Dawn's ion engine technology was tested on the Deep Space 1 mission in the late 1990s, but that spacecraft was designed to test ion propulsion more than explore any bodies. Not seen clearly are the solar arrays which have been folded for flight on each side. When unfurled, the arrays will stretch 20 meters across. They are the most powerful and second largest ever sent beyond Earth orbit. Back to Dawn photos
					A Dawn project engineer provides a size comparison:
					A Dawn project engineer points to one of Dawn's three ion engines:
					Cleanroom garmets must be worn inside this super clean environment: