NASA Scientist Michelle Thaller, Tom Wagner, ICESat-2 Program Scientist, NASA Headquarters, center, and Bill Barnhart, ICESat-2 Program Manager, Northrop Grumman, 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)