The Thule Ballistic Missile Early Warning Radar System (Thule BMEWS) is located at the Thule Air Base in northwestern Greenland. Positioned between Europe and North America, it is a key element of the U.S. defense strategy and an essential part of the U.S. missile defense architecture. Its function is to detect, track, and provide tactical warning and attack assessment of ballistic missiles launched against the United States, Canada, and the United Kingdom.

The Thule BMEWS is a 2-faced phased array radar that operates in the UHF (420-450 MHz) frequency range. It is currently part of the larger BMEWS radar network, which dates back to the early 1960s, and includes radars located in Fylingdales, United Kingdom, and Clear, Alaska. The Thule radar became operational in 1953, and served as a key NATO listening post during the Cold War. It is currently operated by the U.S. Air Force 12th Space Warning Squadron.