The United States Space Force (USSF) is the space service branch of the United States Armed Forces and part of the civilian-led Department of the Air Force, which is led by the Secretary of the Air Force. The military head of the U.S. Space Force is the chief of space operations, who is assisted by the vice chief of space operations and senior enlisted advisor of the Space Force. It achieved independence on 20 December 2019 from the U.S. Air Force, but directly traces its history through Air Force Space Command to 1 September 1982, with even earlier history traced to the Western Development Division established on 1 July 1954.