... Tonight's Sky . ... Sky this Month . ... Sky this Week . ... Tune into the Asteroid Day press conference . ... Dawn spacecraft sees hydrated minerals on giant asteroid . The source of the hydrogen within Vestaт??s surface appears to be hydrated minerals delivered by carbon-rich space rocks that collided with the asteroid at speeds slow enough to preserve their volatile content. ... NASAт??s Dawn spacecraft has revealed that the giant asteroid Vesta has its own version of ring around the collar. ...