Dawn sets off on asteroid trip.

The Dawn spacecraft successfully lifted off on 27 September on a 5-billion-kilometer odyssey into the heart of the asteroid belt.

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Dawn's goal is to characterise the conditions and processes of the solar system's earliest epoch 4.5 billion years ago by investigating in detail the massive asteroid Vesta and the dwarf planet Ceres. They reside between Mars and Jupiter in the asteroid belt. Scientists theorise these were budding planets never given the opportunity to grow. However, Ceres and Vesta each followed a very different evolutionary path during the solar system's first few million years. By investigating two diverse asteroids during the spacecraft's eight-year flight, the Dawn mission aims to unlock some of the mysteries of planetary formation.

Dawn will be the first spacecraft to orbit an object in the asteroid belt and the first to orbit two bodies after leaving Earth. Recent images taken by NASA's Hubble Space Telescope raise further intriguing questions about the evolution of these asteroids. Dawn was launched on a Delta II 7925-H, a heavier-lift model of the standard Delta II that uses larger solid rocket boosters.

Orbital Sciences Corporation designed and built the Dawn spacecraft. Programme cost is $343.5 million (not including the launch vehicle), consisting of $267 million for spacecraft development and $76.5 million for mission operations.