Michael A'Hearn, EPOXI Principal Investigator, University of Maryland, holds a plastic bottle containing ice to illustrate a point during a press conference, Thursday, Nov. 18, 2010, at NASA Headquarters in Washington. The press conference was held to discuss the Nov. 4 successful flyby of Comet Hartley 2 by NASA's EPOXI Mission Spacecraft. Images from the flyby provided scientists the most extensive observations of a comet in history. Photo Credit: (NASA/Paul E. Alers)