NASA's Deep Impact spacecraft completed a firing of its onboard rocket motors earlier today. The maneuver began at 1 p.m. PDT (4 p.m. EDT), lasted 71 seconds, and changed its velocity by 4.5 mph (2 meters per second). The rocket burn was performed to keep the venerable comet hunter's options open for yet another exploration of a solar system small body, this time a possible future visit to a small near-Earth asteroid called 2002 GT.
Deep Impact was launched in January 2005. On July 3, 2005, the spacecraft deployed an impactor that was "run over" by the nucleus of comet Tempel 1 on July 4 while the main spacecraft imaged the event. Sixteen days after that comet encounter, the Deep Impact team placed the spacecraft on a trajectory to complete a bonus mission. The extended mission of the Deep Impact spacecraft culminated in the successful flyby of comet Hartley 2 on Nov. 4, 2010.
To date, Deep Impact has traveled about 4.2 billion miles (6.75 billion kilometers) in space.