The United States Air Force, is the aerial and space warfare service branch, of the United States Armed Forces. Initially formed as a part of the United States Army, on 1 August 1907, the Air Force, was established as a separate branch of the U.S. Armed Forces, on 18 September 1947, with the passing of the National Security Act of 1947. The U.S. Air Force is the largest and most technologically advanced air force in the world. The Air Force articulates its core missions as air and space superiority, global integrated intelligence, surveillance and reconnaissance, rapid global mobility, global strike, and command and control.