D-21: This Crazy Looking Mach 3 Drone Tried to Spy on China's Nuclear Bomb Tests

David Axe

Security,

So what happened?

The military and intelligence communities in the late 1960s hoped the D-21 would help the United States to spy on strategic targets more reliably than a satellite could do at that time, and without risking a human pilot.

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 two months ago.)

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.

The drone followed a pre-programmed flight path and maintained only intermittent radio contact with the launch plane that allowed an operator to monitor the drone's performance. As it reached its final waypoint, the D-21 jettisoned a capsule containing its exposed film then self-destructed.

The film descended on a parachute. The plan was for a special JC-130 transport plane to snatch the parachute in mid-air. Failing that, a Navy ship could fish the capsule from the ocean.

The military and intelligence communities in the late 1960s hoped the D-21 would help the United States to spy on strategic targets more reliably than a satellite could do at that time, and without risking a human pilot.