NASA's air quality research aircraft lands at Osan
NASA’s Armstrong Flight Research Center DC-8 aircraft parks on the flightline at Osan Air Base, Republic of Korea, April 27, 2016. The research aircraft is at Osan as part of a six-week cooperative Korean and U.S. air-quality study to advance the ability to monitor air pollution from space. (U.S. Air Force photo by Tech. Sgt. Travis Edwards/Released)