All About Comets
Colliding & observing
The EPOXI and Deep Impact missions have provided scientists with extremely valuable data on the nature of comets. EPOXI was the second mission to use the Deep Impact vehicle for comet research. On Nov. 4, 2010, the spacecraft approached Comet Hartley 2 at a distance of about 700 kilometers (434 miles). The observation was the fifth time that a comet has been imaged that close, and the first time in history that two comets have been imaged with the same instruments and same spatial resolution.
Built for a July 2005 mission, the Deep Impact spacecraft collided with deep-space comet Tempel 1 and excavated material from the nucleus of the comet. Using its onboard instruments, Deep Impact observed the nucleus of the comet, giving scientists an unprecedented view of the characteristics of comets and the materials inside.