Tech. Sgt. Daniel Keller, a combat controller in the 123rd Special Tactics Squadron, stands at attention during an award ceremony at the Kentucky Air National Guard Base in Louisville, Ky, Aug.13, 2019. At the ceremony, Air Force Chief of Staff Gen. David L. Goldfein presented Keller with the Air Force Cross, which Keller earned for valor on the battlefield in Afghanistan. (U.S. Air National Guard photo by Staff Sgt. Joshua Horton)