At Bletchley Park in the 1940s, Alan Turing and colleagues decrypted Enigma messages, providing ULTRA intelligence that aided Allied victory. The United States began launching military communications satellites in the 1960s, and by 1982 the second- and third-generation DSCS satellites offered nuclear-hardened, anti-jamming, high-data-rate links worldwide. In 1976, Diffie–Hellman introduced public-key cryptography, and DES was…
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Geostationary orbit sits at about 35,786 km above the equator and completes a sidereal day (~23h56m), so satellites appear fixed over one longitude; Arthur C. Clarke popularized it in 1945, giving the region the nickname the Clarke Belt. A GEO satellite remains stationary relative to the ground, allowing ground antennas to point at a fixed…
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The United States operates the Advanced Extremely High Frequency (AEHF) constellation, delivering jam-resistant, global, protected military communications including nuclear command and control links. Navstar GPS is a 31-satellite global navigation system that provides precise positioning, navigation, and timing to guide munitions such as JDAM and to synchronize encrypted networks. Defense Support Program (DSP) and the…
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