By 1958, a prototype of the Ballistic Missile Early Warning System (BMEWS) at the Trinidad, British West Indies, site provided surveillance and tracking of ballistic missiles, as an overall step in the BMEWS development. The Trinidad Radar Site commenced operation on 4 February 1959, gathering data on missiles fired on the Atlantic Missile Range, satellites, and meteors. In February 1962 the Radio Corporation of America (RCA) assumed responsibility for the operation of the Trinidad Radar.
In late 1959, ARPA opened the 474L System Program Office (SPO), which it tasked to develop techniques and equipment for tracking space objects and detecting incoming Soviet ICBMs. By the mid-1960s, the 474L SPO had activated three Ballistic Missile Early Warning System (BMEWS) radars located at Thule AB, Greenland (1960); Clear AFS, Alaska (1961); and RAF Fylingdales Moor, England (1963). These radars provided the capability to detect an incoming ICBM attack and provide 15 minutes warning. They also provided tracking data on most orbiting satellites. ARDC set up the Interim National Space Surveillance Control Center at Hanscom AFB in January 1960. The Air Force designated ADC the primary user of spacetrack data. BMEWS Site II is located at Clear Air Force Station, Alaska. It is 40 miles north of Mount McKinley and 80 miles south of Fairbanks. It manages and operates three AN/FPS-50 detection radars that cover 120 degrees in azimuth and approximately 3,000 nautical miles in range. It also has one AN/FPS–92 tracking radar.