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The 12th Space Warning Squadron (12 SWS) operates the Upgraded Early Warning Radar (UEWR), formerly the Ballistic Missile Early Warning System (BMEWS) - Site 1, at Thule Air Base, Greenland. 12 SWS is part of the Integrated Tactical Warning and Attack Assessment network, which provides early warning of ballistic missile launches to National Command Authorities via the Missile Warning Center and North American Aerospace Defense Command (NORAD).


The 12 SWS has three missions: missile warning, missile defense, and space domain awareness. A 3-member crew executes the missile warning and missile defense missions by detecting and providing assessment data on Intercontinental Ballistic Missiles (ICBMs) and Sea-Launched Ballistic Missiles (SLBMs) threatening the United States and/or Canada, in support of the Department of the Air Force Arctic Strategy and the National Defense Strategy. The 12 SWS secondary mission provides space surveillance data on earth-orbiting objects to the 18th Space Control Squadron at Vandenberg Space Force Base, California, in support of United States Space Command's space control missions. Additionally, the unit also provides data to the National Space Defense Center (NSDC) and the National Air and Space Intelligence Center (NASIC).


UEWR is an AN/FPS-132, two-sided, solid-state phased-array radar system. Unlike mechanical radars, UEWR’s antenna elements 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 and uses up to 870 kW of power. 12 SWS operates the UEWR 24 hours per day, 365 days a year and is comprised of United States and Canadian military personnel and contractors.


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 AB, much as it exists today, was built during the summers of 1951 and 1952.

The origin of 12 SWS dates 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. Air Force Space Command (AFSPC) assumed control of Thule AB in 1983 and the unit was re-designated as the 12 SWS in 1992. In June 1987, the BMEWS mechanical radar was upgraded to the more efficient and capable solid-state, phased array system in existence today, and is now known as the UEWR.

On Dec. 20, 2019, United States Space Force was officially established and 12 SWS became a part of the newest branch of the United States Department of Defense. On July 24, 2020, the 12 SWS was transferred to Space Delta 4, Buckley AFB.