EPOXI is a NASA unmanned space mission led by the University of Maryland using the existing Deep Impact vehicle to begin a new series of observations. It first investigated extrasolar planets and, on November 4, 2010, it performed a close approach to the comet 103P/Hartley (alternately named Hartley 2). The new mission was originally announced on 3 July 2007 as including flyby of comet 85P/Boethin, but Boethin was too small and faint for its orbit to be calculated accurately, so the mission was subsequently retargeted for a 103P/Hartley flyby. NASA and the University of Maryland confirmed funding for the 103P/Hartley flyby in news releases issued on December 13, 2007.
EPOXI combines two targets: the Deep Impact Extended Investigation (DIXI), and the Extrasolar Planet Observation and Characterization (EPOCh). Deep Impact will conduct both missions, the Extrasolar Planet Observation and Characterization during the cruise phase to 103P/Hartley, and the Deep Impact Extended Investigation at flyby. The spacecraft was also used as a test platform for a delay-tolerant networking transmission while at a distance of 20 million miles from Earth.
As of November 2011, there will be a senior review of all operating planetary exploration missions at NASA. That will likely include a review of the status of the Deep Impact Flyby spacecraft to determine whether an additional extended mission should be approved. Decisions will not occur until early 2012.
NASA's Jet Propulsion Laboratory, in Pasadena, California., manages EPOXI for NASA's Science Mission Directorate, Washington. The Principal Investigator is Michael A'Hearn.