About this Unit
NAVSPASUR, short for Naval Space Surveillance System, was a United States Navy radar network established during the early 1960s. Its primary mission was to detect and track satellites and other objects in Earth's orbit, providing vital space situational awareness during the Cold War. The system consisted of a series of transmitting and receiving stations spanning the southern United States, forming an electronic "fence" across the continent. Operated for decades by the U.S. Navy, NAVSPASUR was transferred to the United States Air Force in 2004 and later became part of the Air Force Space Surveillance System, continuing its legacy in American space defense.
Historical Facts
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Origins in the Cold War: NAVSPASUR, or the Naval Space Surveillance System, was established in 1958 at the height of the Cold War to help the United States detect and track Soviet satellites and other space objects.
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First Operational Space Fence: NAVSPASUR was the world's first operational space surveillance system, earning the nickname "Space Fence" for its ability to detect objects crossing a radar "fence" stretching across the southern United States.
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Massive Radar Coverage: The system consisted of three transmitting stations and six receiving stations, forming a line approximately 3,000 miles long from California to Georgia.
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Passive Detection: NAVSPASUR used continuous wave radar, which meant it could detect objects in low Earth orbit without actively "pinging" them—if an object passed through the radar beam, it would reflect the signal and be detected.
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Real-time Tracking: The system could track objects as small as a basketball (around 29 cm) and provided real-time data to the U.S. military and NASA.
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Public Space Catalog: Data from NAVSPASUR contributed to the public catalog of satellites and space debris maintained by NORAD, helping scientists and satellite operators avoid collisions.
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Hurricane Katrina Impact: In 2005, Hurricane Katrina severely damaged the Lake Kickapoo, Texas, transmitter—one of the primary stations—demonstrating the vulnerability of terrestrial space surveillance assets to natural disasters.
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Transfer to Air Force: In 2004, operational control of NAVSPASUR was transferred from the U.S. Navy to the U.S. Air Force, reflecting the increasing importance of space in military operations.
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Deactivation and Replacement: The original NAVSPASUR system was deactivated in 2013 and replaced by the Space Fence radar system, which uses advanced S-band technology for even finer detection.
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Unusual Encounters: In 1960, the system famously detected the mysterious "Black Knight" satellite—an unidentified object in polar orbit that sparked speculation and conspiracy theories about its origin.
