U.S. Air Force Col. William Clark, 455th Expeditionary Mission Support Group commander, speaks during the 455th EMSG change of command ceremony at Bagram Airfield, Afghanistan, Aug. 3, 2015. The 455th MSG is comprised of five squadrons responsible for communications, civil engineer operations, force support, logistics readiness, and security forces. (U.S. Air Force photo by Tech. Sgt. Joseph Swafford/Released)