EPOXI

EPOXI was a compilation of NASA Discovery program missions led by the University of Maryland and principal investigator Michael A'Hearn, with co-operation from the Jet Propulsion Laboratory and Ball Aerospace. EPOXI uses the Deep Impact spacecraft in a campaign consisting of two missions: the Deep Impact Extended Investigation (DIXI) and Extrasolar Planet Observation and Characterization (EPOCh). DIXI aimed to send the Deep Impact spacecraft on a flyby of another comet, after its primary mission was completed in July 2005, while EPOCh saw the spacecraft's photographic instruments as a space observatory, studying extrasolar planets.

DIXI successfully sent the Deep Impact spacecraft on a flyby of comet Hartley 2 on November 4, 2010, revealing a "hyperactive, small and feisty" comet, after three gravity assists from Earth in December 2007, December 2008 and June 2010. The DIXI mission was not without problems, however; the spacecraft had initially been targeted for a December 5, 2008 flyby of comet Boethin, though, the comet could not be located, and was later declared a lost comet, prompting mission planners to reorganize a flyby of an alternative target, Hartley 2. After its flyby of Hartley 2, the spacecraft was also set to make a close flyby of the Apollo asteroid (163249) 2002 GT in 2020. The mission was suspended altogether, however, after contact with the spacecraft was suddenly lost in August 2013 and attempts to re-establish contact in the month following had failed. Mission scientists theorized that a Y2K-like problem had plagued the spacecraft's software.