Cheyenne Mountain: 440L radar detects unidentified returns
On March 1, 1968, the US Air Force handed over the 440L Over-the-Horizon Forward Scatter Radar System to NORAD's Cheyenne Mountain facility. Shortly after, it began detecting unidentified radar echoes.
Background
Background
The 440L system, an over-the-horizon forward-scatter radar, was developed in 1960–1962 to monitor Soviet missile launches. It used high-frequency signals reflected between the ionosphere and the earth's surface to detect the disturbances caused by rockets.
Handover and Operation
On March 1, 1968 the system was handed over by Air Force Intelligence to the NORAD centre at Cheyenne Mountain, Colorado. It first reached an initial operational capability and was integrated into the global sensor network. Components were also located at sites such as RAF Feltwell.
Unidentified Signals
Shortly after entering service, the radar registered unknown returns that did not correspond to any known missile launches. This marked an early military contact with unexplained phenomena in the UAP context.
Significance
The events point to the role of advanced military technology in detecting UAP during the Cold War. Sources: Clark III 811; Clark IV 904.