Air Force Chief of Staff Gen. David L. Goldfein, left, pins the Air Force Cross to the uniform of Tech. Sgt. Daniel Keller, a combat controller in the 123rd Special Tactics Squadron, during a ceremony at the Kentucky Air National Guard Base in Louisville, Ky., Aug.13, 2019. Keller earned the award — second only to the Medal of Honor — for valor on the battlefield in Afghanistan. (U.S. Air National Guard photo by Staff Sgt. Joshua Horton)