Dawn of the Solar System

NASA's Dawn mission to the asteroid belt-- a mission that has been cancelled and reinstated-- is set for launch Thursday from Cape Kennedy.

Dawn's mandate is to study the early Solar System by focusing on two of the largest bodies in the asteroid belt, Ceres and Vesta. Scientists believe studying those bodies can reveal how planets may have formed. Ceres, which is now officially a dwarf planet, may be especially interesting and important. Telescopic studies suggest it may have a thin atmosphere, and there are indications it might have water under its surface. Some scientists suggest Ceres may have six times the amount of fresh water that Earth has. If that estimate turns our to be even remotely accurate, Ceres could eventually become a key deep space base as we push towards the stars.

NASA is under pressure to launch Dawn by the end of October. If it doesn't, the orbital interplay of the bodies involved won't be right again until 2022.