U.S. Air Force Staff Sgt. Robert Gallagher, 7th Aircraft Maintenance Squadron crew chief, prepares to marshal a B-1B Lancer during Exercise Constant Vigilance 16, April 10, 2016, at Dyess Air Force Base, Texas. Constant Vigilance 16 is one of many training operations conducted by Air Force Global Strike Command to ensure Airmen are ready to perform nuclear deterrence operations and long-range strike missions. (U.S. Air Force photo by Airman 1st Class Rebecca Van Syoc/Released)