The 12th Space Warning Squadron (12 SWS) operates the Upgraded Early Warning Radar (UEWR), formerly the Ballistic Missile Early Warning System (BMEWS) - Site I, at Thule Air Base, Greenland.
UEWR is an AN/FPS-132, two-sided, solid-state phased-array radar system used to perform multiple missions. 12 SWS has three missions: Missile warning, missile defense, and space surveillance. Its primary and co-primary missions are missile warning and missile defense against Intercontinental Ballistic Missiles (ICBMs) and Sea-Launched Ballistic Missiles (SLBMs) threatening the United States and/or Canada. 12 SWS completes these missions by furnishing warning and attack assessment data on all ICBMs and SLBMs penetrating its coverage area.
12 SWS has a secondary mission of providing space surveillance data on earth-orbiting objects to the Joint Space Operations Center at Vandenberg Air Force Base, CA in support of United States Strategic Command's space control missions.
The squadron is a unit of the 21st Space Wing, Peterson AFB, under Air Force Space Command. Operationally, it is part of the Integrated Tactical Warning and Attack Assessment network. This system provides the US National Command Authority with early warning and of ballistic missile launches and information on their probable impact points. This data is then provided to the Missile Warning Center at Cheyenne Mountain Air Force Station in Colorado Springs, CO. At Cheyenne Mountain, data from all sensors is integrated by the U.S. Strategic Command's Missile Correlation Center and displayed in the command post of North American Aerospace Defense Command (NORAD). NORAD evaluates the integrated sensor information and notifies the national leadership in Ottawa and Washington DC whether or not North America is under ballistic missile attack. In addition, NORAD provides the national leadership with an attack assessment of the probable impact points in North America.
12 SWS operates its UEWR 24 hours per day, seven days per week and is comprised of US and Canadian military personnel and contractors. The system’s antennas do not move. The radar beam is electronically steered to a programmed location. This process, accomplished in milliseconds, increases capabilities and decreases response time. Each radar face provides 120 degrees azimuth coverage, for a total of 240 degrees coverage. Each array face contains 3,589 antenna elements.
In 1946, a combined Danish-American radio and weather station was established at Dundas, later called Thule. International tensions prompted Denmark and the United States to sign a defense treaty allowing the construction of a complete air base. Thule, much as it exists today, was built during the summers of 1951 and 1952.
The origin of 12 SWS goes back to the establishment of the BMEWS Site 1 in 1961. Throughout the years, several commands were responsible for the base, including Northeast Air Command, Air Defense Command and Strategic Air Command.
The unit was first designated as the 12th Missile Warning Squadron and later became the 12th Missile Warning Group. AFSPC took control of Thule in 1983 and the unit was redesignated as the 12th Space Warning Squadron in 1992. In June 1987, the old mechanical radar was upgraded to the more efficient and capable solid-state, phased array system.