(a) The term “United States Space Force” refers to a new branch of the United States Armed Forces to be initially placed by statute within the Department of the Air Force.
Sec. 7. Associated Elements.
(a) A Unified Combatant Command for space, to be known as the United States Space Command, will be established consistent with law, as directed on December 18, 2018.
A major command is a significant U.S. Air Force organization subordinate to Headquarters, US Air Force. Major commands have a headquarters staff and subordinate organizations, typically formed in numbered air forces, centers, wings, and groups.Historically, a MAJCOM is the highest level of command, only below Headquarters Air Force (HAF), and directly above Numbered Air Forces (NAFs).
Air Force Instruction 38-101, AIR FORCE ORGANIZATION, 4 APRIL 2006 (with Change 2, dated 20 July 2006), paragraph 2.2.2., page 10.
A unified combatant command (UCC) is a Department of Defense Command that is composed of forces from at least two Military Departments and has a broad and continuing mission.
Title 10, U.S.C. Sections 161–168.
And see Joint Pub 1, p. GL-11.