The 509th Operations Group (509 OG) is the flying component of the United States Air Force 509th Bomb Wing (509 BW), assigned to Whiteman Air Force Base, Missouri. It is equipped with all 20 of the USAF's B-2 Spirit stealth bombers, flown by its 393rd Bomb Squadron. Its 13th Bomb Squadron, the training unit for the 509th, provides training in T-38 Talon trainers as well as in the 393rd's B-2 Spirits. The 509 OG traces its history to the World War II 509th Composite Group (509 CG), which conducted the atomic bombings of Hiroshima and Nagasaki, Japan, in August 1945.