The EPOXI mission is a NASA Discovery Mission of Opportunity combining two separate investigations : Extrasolar Planet Observation and Characterization ( EPOCh ) and Deep Impact eXtended Investigation ( DIXI ) . Both investigations reused the DI instruments and spacecraft that successfully flew by the comet Tempel-1 ( 4 July 2005 ) . For EPOCh , the goal was to find exoplanets with the high resolution imager , while for DIXI it was to fly by the comet Hartley 2 ( 4 Nov 2010 ) . This paper documents the navigation experience of the earlier ma - neuver analyses critical for the EPOXI mission including statistical ? V analyses and other useful analyses in designing maneuvers . It also recounts the trajectory design leading up to the final reference trajectory to Hartley 2 .