This supersonic drone scout provoked China

The crash came at the wrong time. In early 1971, the United States and communist China cautiously approached one another, just as US President Richard M. Nixon had indicated during the 1968 election campaign. And then this: On March 20, a mysterious plane crashed in a forest in Yunnan province. The wreck had broken into numerous pieces, the largest piece falling on a slope at the edge of a clearing. Residents of the area collected numerous remains, the military helped.

In Beijing, the experts of the Chinese secret service assumed that one of the already legendary "Oxcart" machines, technically speaking: a Lockheed A-12, or its further development "Blackbird", the SR-71, had crashed. The exterior of the recovered wreckage was strongly reminiscent of the few images of this secret project known at the time. These were extremely fast high-altitude reconnaissance aircraft that flew a few missions over Vietnam in 1967 and several missions over North Korea the following year (by the way, the boarding of the USS "Pueblo" by North Korean marines was confirmed).

In the following two years the number of similar flights over Laos and Vietnam increased sharply, with the further developed model SR-71. But initially not about China. In any case, the radar systems of the communist dictatorship did not register anything of the sort (and if they did, it was not announced).

According to CIA records, which ran the reconnaissance program in conjunction with the USAF, an offshoot of the A-12/SR-71 program first flew over China on November 9, 1969: the first D-21 supersonic reconnaissance drone. A total of four missions, code name: "Senior Bowl", are documented in the documents of the US secret services, the last on March 20, 1971.

The D-21 followed from the realization that long flights over potentially hostile territory would significantly increase the risk of downing even extremely powerful machines like the A-12 or SR-71. On October 30, 1967, Soviet anti-aircraft missiles launched in North Vietnam slightly damaged an "Oxcart". The CIA and USAF did not want to go through another embarrassing failure like the shooting down of the U-2 pilot Gary Powers over the Soviet Union in 1960.

So Lockheed developed an unmanned drone from the technology of the two manned reconnaissance planes. It should be as fast and fly as high as "Oxcart" and "Blackbird" at more than three times the speed of sound, but much lighter to keep the loss in a crash or kill manageable.

In order to limit costs, the engineers at Lockheed's special department "Skunk Works", officially the "Advanced Development Programs" in California, to be precise: on the Hollywood-Burbank Airport site north of Los Angeles, renounced the drone's take-off and landing capabilities . The construction, called the D-21, was to be launched from a manned aircraft, after use to eject a capsule with the exposed films and the valuable camera technology, and then to self-destruct.

The only thing the D-21 had in common with drones, as the term is understood in the 21st century, was that it was an unmanned aerial vehicle that was supposed to take over (or at least: should be able to take over) missions previously piloted by humans had fulfilled. The first five test flights in 1967/68 all failed - for various reasons. Only the sixth attempt ended successfully. In the following six tests, the success rate increased to 50 percent. The D-21 has now been declared operational.

Externally, the D-21 closely resembled one of the two engine nacelles of the A-12. The shape followed the model completely, and the material and construction of the fuselage largely corresponded to that of the manned aircraft.

The drive, on the other hand, was not: Different versions of the high-tech Pratt turbine were used in “Oxcart” and “Blackbird”.

After the test flights, which were only partially successful, the "Skunk Works" had changed the mission profile: instead of an A-12 converted to the mother aircraft, the D-21 was to be started by a Boeing B-52 from now on. However, because this huge strategic bomber was not supersonic and therefore could not bring the drone to the speed required for the effective operation of the ramjet engine, a rocket-powered booster was added. At 14 meters long and weighing six tons, it was larger and heavier than the actual D-21, which was 13.1 meters long, had a wingspan of 5.8 meters and weighed five tons when capable of flying.

The target of the first (and as it turned out: only) four missions of the D-21 was the Red Chinese nuclear test site on the dry salt lake Lop Nur in Central Asia. Mao Tse-tung had had a nuclear test site set up here since 1959, where five years later China's first nuclear weapon and in 1967 its first own hydrogen bomb were detonated. In total, there were nine surface tests and one underground up to the first D-21 flight here.

The first flight on November 9, 1969 was a failure because the drone flew over Lop Nur and took photos, but for unknown reasons the controls that were to initiate the turn back towards Japan failed. The D-21 just kept flying and crashed in the USSR, where the KGB salvaged debris and considered a replica, which never happened.

The second mission followed 13 months later. This time everything seemed to go smoothly: the D-21 reached the target area, took pictures, turned around and reached the Sea of ​​Japan, where the capsule with cameras and film was to be parachuted and recovered in flight by a special US capture aircraft. However, the parachute did not deploy, and the payload fell into the sea and sank.

On the third mission, on March 4, 1971, the parachute deployed but failed to catch and again lost the camera and film capsule. The fourth and last mission failed on March 20, 1971 on the return flight over Yunnan Province for unknown reasons.

Because this time there was debris as evidence and US President Nixon did not want to provoke the People's Republic of China, the D-21 flights were suspended and the program ended. Of the 38 drones built, 21 took off; the remaining 17 were put into storage. In 1977, the USAF confirmed the existence of this program after privately taken photos surfaced. Ten of the D-21s are on display at various aviation museums across the United States as of 2023, and at least one is in an Arizona aircraft graveyard. The debris of the Exemplar that crashed over Yunnan has been on public display in Beijing since 2010.

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