Airman 1st Class Clay Steiber, 28th Aircraft Maintenance Squadron crew chief, takes cover during an operation readiness exercise at Ellsworth Air Force Base, S.D., March 31, 2015. The training exercise evaluated a variety of the installation’s units that help support the operational mission at Ellsworth, including aircraft maintenance, base defense, damage assessment, Chemical, Biological, Radiological, Nuclear, and High Yield Explosives (CBRNE) reconnaissance. (U.S. Air Force photo by Senior Airman Anania Tekurio/Released)