The United States Space Force (USSF) is the space service branch of the U.S. Armed Forces, one of the eight U.S. uniformed services, and the world's first and currently only independent space force. Along with its sister-branch, the U.S. Air Force, the Space Force is part of the Department of the Air Force, one of the three civilian-led military departments within the Department of Defense. The Space Force, through the Department of the Air Force, is overseen by the Secretary of the Air Force, a civilian political appointee who reports to the Secretary of Defense, and is appointed by the President with Senate confirmation. The military head of the Space Force is the Chief of Space Operations who is the most senior Space Force officer unless a Space Force officer is serving as either Chairman or Vice Chairman of the Joint Chiefs of Staff. The Chief of Space Operations exercises supervision over the Space Force's units and serves as one of the Joint Chiefs of Staff. The Space Force is the smallest U.S. armed service, consisting of 6,434 personnel and operating 77 spacecraft. Major spacecraft and systems include the Space Fence, Global Positioning System constellation, military satellite communications constellations, Boeing X-37B spaceplane, U.S. missile warning system, U.S. space surveillance network, and the Satellite Control Network. Under the Goldwater–Nichols Act, the Space Force is responsible for organizing, training, and equipping space forces, which are then presented to the unified combatant commands, predominantly to United States Space Command, for operational employment. The U.S. Space Force traces its roots to the beginning of the Cold War, with the first Army Air Forces space programs starting in 1945. In 1954, the Western Development Division, under General Bernard Schriever, was established as the first dedicated space organization within the U.S. Armed Forcesand continues to exist as the Space Force's Space and Missile Systems Center. Military space forces were organized under several different Air Force major commands until they were unified when Air Force Space Command was established on 1 September 1982. U.S. space forces first began conducting combat support operations in the Vietnam War and continued to provide satellite communications, weather, and navigation support during the 1982 Falklands War, 1983 United States invasion of Grenada, 1986 United States bombing of Libya, and 1989 United States invasion of Panama. The first major employment of space forces culminated in the Gulf War, where they proved so critical to the U.S.-led coalition, that it is sometimes referred to as the first "space war". The first discussions of creating a military space service occurred in 1958, and the idea was also being considered in 1982 by President Ronald Reagan. The 2001 Space Commission argued for the creation of a Space Corps between 2007 and 2011, and a bipartisan proposal in the U.S. Congress would have created a U.S. Space Corps in 2017. United States Space Force (USSF) was founded on December 20, 2019, just over 2 years ago. The United States Space Force Act, developed by Democratic representative Jim Cooper and Republican representative Mike Rogers, was signed as part of the National Defense Authorization Act by President Donald Trump, reorganizing Air Force Space Command into the United States Space Force, and creating the first new independent military service since the Army Air Forces were reorganized as the U.S. Air Force in 1947.