Dawn probe slips Vesta's grip, heads for icy dwarf planet

NASA's Dawn spacecraft has left the gravitational pull of the giant asteroid Vesta behind after over a year of study and is rocketing towards the dwarf planet Ceres.

The satellite, launched in September 2007, has been exploring and mapping Vesta for the first time, showing agency boffins an exotic and diverse building block of planet that can help them figure out how our solar system was formed.

Dawn pulled away from Vesta easily and is now on its way to Ceres, our inner solar system's only dwarf planet and its largest asteroid. The spacecraft is expected to arrive in early 2015.

"As we respectfully say goodbye to Vesta and reflect on the amazing discoveries over the past year, we eagerly look forward to the next phase of our adventure at Ceres, where even more exciting discoveries await,” said Robert Mase, Dawn project manager, based at NASA's Jet Propulsion Laboratory.

Ceres is a rock-ice body around 950km in diameter, according to what boffins have been able to discover so far. They theorise that the dwarf may have active hydrological processes, giving it seasonal polar caps and/or a thin, permanent atmosphere that distinguishes it from other small planets, and Dawn has been sent to help test these theories.

Boffins also reckon that both Vesta and Ceres could have been budding planets that never got the chance to grow up because of the gravitational stirrings of Jupiter.

Dawn is the first spacecraft to orbit a body in the main asteroid belt and its mission is the first to orbit two targets. ®