Deep Impact's primary mission was to deliver a special impactor spacecraft into the path of Comet Tempel 1.The spacecraft -- and many ground-based observers -- observed the impact and the ejected material. Scientists were surprised the cloud was composed of a fine, powdery material, not the expected water, ice and dirt. The spacecraft found the first evidence of surface ice on the surface of a comet instead of just inside a comet.
The flyby spacecraft is now on an extended mission -- called EPOXI -- to study and search for planets orbiting distant stars. The spacecraft also observed a second comet, Hartley 2, making its closest approach on 4 November 2010.