Artist's impression: W Hartmann/JPL/NASA
Apparently the mission was stopped after a US congressional hearing on NASA's science budget, reports NASAWatch.com, a website run by former NASA employee Keith Cowing.
Both asteroids were thought to be remnants of the first objects formed in the solar system. But they show mysterious differences in their structures – Vesta has melted and separated into layers, while Ceres has not. Dawn was to probe these differences, using close-range scrutiny.
The decision to cancel the mission came after ,more than a month, the agency was expected to complete an extensive review of the mission's progress. In October 2005, NASA ordered Dawn managers to stop work on the mission, citing excessive technical problems and a budget overrun.
More: Dawn asteroid mission killed.
Story Credit: NewScientist.com news service; Kimm Groshong