Deep Impact was the first mission to eject material from a comet's surface.
It is a coincidence that Deep Impact shares its name with a 1998 science fiction disaster film about a comet.
Author Arthur C. Clarke suggested the idea of impacting a comet in his novel 2001: A Space Odyssey
Deep Impact's small probe was the first manmade object to collide with a comet (right).
EPOXI has double meaning. EPO stands for EPOCh the Extrasolar Planet Observation and Characterization phase of mission. XI is short for the spacecraft's extended investigation of comets.
EPOXI is an entirely new mission for a spacecraft already in orbit around our sun.