The 21st Space Wing (21 SW) was the United States Space Force's ground–based missile warning and space control wing. The 21st Space Wing was assigned to Space Operations Command and headquartered at Peterson Air Force Base, Colorado. The 21st Space Wing controlled Peterson Air Force Base, Cheyenne Mountain Air Force Station, Thule Air Base, Clear Air Force Station, Cape Cod Air Force Station, and Cavalier Air Force Station.