U.S. Air Force Master Sgt. Joseph Vaughn, assigned to the 164th Logistics Readiness Squadron, Tennessee Air National Guard, guides a truck to an off-loading dock during the Deployable Air Base System proof of concept exercise at the 31st Tactical Air Base, Poznan-Krzesiny, Poland, July 30, 2018. The exercise tests and enhances the ability to rapidly deploy within theatre, preposition equipment and enables the execution of current operations, exercises and contingencies. (U.S. Army photo by Spc. Craig Jensen)