Bill Barnhart, ICESat-2 Program Manager, Northrop Grumman, left, Doug McLennan, ICESat-2 Project Manager, NASA's Goddard Space Flight Center, center, and Cathy Richardson, Deputy Program Manager, Earth Science Projects Division, NASA's Goddard Space Flight Center, are seen during a NASA Ice, Cloud and land Elevation Satellite-2 (ICESat-2) prelaunch briefing, Thursday, Sept. 13, 2018, at Vandenberg Air Force Base in California. The ICESat-2 mission will measure the changing height of Earth's ice. Photo Credit: (NASA/Bill Ingalls)