In the decades since its reactivation, 20th Air Force has experienced four major command identities. After one year in Strategic Air Command and another year in Air Combat Command, 20th Air Force was moved under Air Force Space Command in 1993. December 2009 marked the final transition of 20th Air Force to the newly created Air Force Global Strike Command. Twentieth Air Force Headquarters' changed its location in 1993, moving from Vandenberg AFB, Calif., to its current home at FE Warren Air Force Base, Wyoming. Today 450 Minuteman III missiles remain on alert.