Mars Comet Encounter Briefing

Jim Green, director, Planetary Science Division, NASA Headquarters, Washington gives remarks during a media briefing where he and other panelists outlined how space and Earth-based assets will be used to image and study comet Siding Spring during its Sunday, Oct. 19 flyby of Mars, Thursday, Oct. 9, 2014 at NASA Headquarters in Washington. Photo Credit: (NASA/Joel Kowsky)