Check Out the D-21: A Mach 3 Drone the U.S. Used to Spy on China's Nuclear Weapons
Surviving D-21s reside at several U.S. museums. China recovered the wreck of one self-destructed D-21 and put it on display in Beijing.
Between 1969 and 1971, the U.S. National Reconnaissance Office deployed super-fast spy drones over China in an abortive attempt to spy on Beijing's nuclear program.
The NRO on March 21, 2019 declassified scores of five-decade-old records documenting the development, deployment and termination of the "Tagboard" drone system.
(This first appeared last month.)
Tagboard's air vehicle was the Lockheed-made D-21 drone. It was an impressive example of brute-force, mid-century engineering.
Made of titanium and weighing 12 tons, the 19-feet-wingspan D-21 in its early forms launched from atop a special variant of the A-12, the CIA's version of the Mach-3 SR-71. The A-12 in essence was the booster for the drone, climbing to 80,000 feet of altitude and accelerating to Mach 3.3 before separating from the pilotless vehicle.
The D-21's ramjet engine took over, allowing it to cruise at three times the speed of sound for as far as 3,000 miles. A 300-pound Hycon HR 335 camera peering through the drone's lower fuselage could capture 5,600 exposures covering an area 16 miles wide and 3,900 miles long.