Ballistic Missile Early Warning System

Common card · No. 372976

The RCA 474L Ballistic Missile Early Warning System (BMEWS, 474L System, Project 474L) was a United States Air Force Cold War early warning radar, computer, and communications system, for ballistic missile detection. The network of twelve radars, which was constructed beginning in 1958 and became operational in 1961, was built to detect a mass ballistic missile attack launched on northern approaches [for] 15 to 25 minutes' warning time also provided Project Space Track satellite data (e.g., about one-quarter of SPADATS observations). BMEWS sites generally used two separate radar systems. The AN/FPS-50 was a long-range system designed to scan the radar horizon and detect missiles as early as possible, and the AN/FPS-49, a highly accurate monopulse radar that would produce accurate tracks on individual targets. During the prototype phase the data collected from these radars was processed by an IBM 709, but this was later replaced by the AN/FSQ-28, which was based on duplexed IBM 7090 processors...

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