Ron Kwok speaks during the press briefing, "First Results from New ICESat-2 Mission, Tuesday, December 11, 2018 at the Marriott Marquis in Washington as part of the American Geophysical Union (AGU) annual meeting. Photo Credit: (NASA/Aubrey Gemignani)

Ron Kwok speaks during the press briefing, "First Results from New ICESat-2 Mission, Tuesday, December 11, 2018 at the Marriott Marquis in Washington as part of the American Geophysical Union (AGU) annual meeting. Photo Credit: (NASA/Aubrey Gemignani)