Vince Houghton - Nuking the Moon - And Other Intelligence Schemes and Military Plots Left on the Drawing Board

But what if we could develop a spy plane without a pilot?

Of course, this is not such a big deal today. Drones are ubiquitous. They’re everywhere. They’re a core part of our military strategy (and also probably driving you crazy in your neighborhood park).

This also wasn’t the first time anyone had thought of building an unpiloted vehicle. “Drones” of some sort or another have been around since as early as World War I, when unmanned aircraft were used as crude aerial ramming missiles.

Kelly Johnson’s idea, however, was to build the first UAV in history specifically designed for intelligence collection. It would eventually be called the D-21, and the CIA and U.S. Air Force project to develop it became known as Tagboard.

It would be the most classified project of Johnson’s storied career.

The concept behindTagboard was… well, simple is the wrong word. The drone would be launched off the back of an A-12, which would already be traveling at about two times the speed of sound, if not faster. The unmanned vehicle would then fly for up to three thousand miles on its own, at speeds of three and a half times the speed of sound and altitudes of between eighty-seven thousand and ninety-five thousand feet. So high and so fast that no air defense at the time stood a chance to shoot it down. It would carry a camera for aerial reconnaissance, but unlike the U-2 or A-12/SR-71, the drone was not designed to bring the film back to base for processing and developing. Instead, once all of the mission’s required pictures were taken, the aircraft would eject the film canister, which would be slowed by a parachute until it was plucked out of the air by a specifically modified C-130 Hercules. This might sound a little crazy, but it’s exactly how the film from the first three American spy satellites was collected. The Corona, Gambit, and Hexagon (the first U.S. spy satellites—and the last to use physical film) all dropped their photographic payload through the atmosphere to be grabbed by waiting aircraft. This process actually almost always worked. On one or two occasions, the C-130 missed the precious intelligence cargo and it landed in the ocean. But like any good mission, there were contingency plans put in place. In case of a water landing, special flotation devices were attached to the film canister. It would theoretically float on top of the water until it could be successfully recovered. Theoretically.

There was one major difference between the film retrieval process of the early satellites and the D-21 drone: Once the drone had ejected its film, the D-21 was designed to self-destruct, leaving no evidence of the new American spy technology. The trip would be one-way.

The D-21 would be propelled to these extraordinary speeds by what is known as a “ramjet” engine. A ramjet is a special kind of propulsion system that uses the engine’s forward motion to bring air into it. The engine compresses that air, combusts it, and then shoots it out the back (as thrust) at a ridiculously high speed. Ramjets are built for going really flipping fast. They don’t even work at low speeds, and are most efficient at around 2,300 mph (Mach 3).

Kelly Johnson and Lockheed had been playing around with ramjet engines since the 1940s. The experimental aircraft X-7, which operated between 1951 and 1960, used a ramjet engine to reach speeds of Mach 4.3 and altitudes of nearly a hundred thousand feet. The X-7 would eventually evolve into the AQM-60 Kingfisher system, used as targets to test early American anti–ballistic missile surface-to-air (SAM) systems. And kick their collective behinds. The Kingfisher was too good. It was too fast to shoot down. Eventually the program was canceled, mainly because it made the military look so inept.

One of the trade-offs of all this speed is endurance. Ramjets (at least those built in the 1960s) could only operate for about thirty minutes at a time, so despite their moxie, they had a very short range. Johnson, however, didn’t care about this problem. The D-21 was going to be brought to the edge of the surveillance area by another plane, then set free to fly its mission. It didn’t need to go all that far.

Johnson and his team produced a full-scale mock-up of the D-21 in only six weeks, and then began conducting tests at an area known as Groom Lake (you might have heard of it called by a different name—Area 51). The experiments centered on testing the aircraft’s ability to avoid radar detection (these were called RCS tests, for “radar cross section”). The drone had the smallest RCS of anything Lockheed had ever designed. It also underwent wind tunnel testing to make sure the drone could, you know, fly. In March 1963, the CIA and the U.S. Air Force jointly contracted Lockheed to commence development of the aircraft.

The specially modified A-12 from which the D-21 would be launched was rechristened the M-21—the “M” stood for “mother” or “mother ship,” and the “D” in D-21 stood for “daughter.” The A-12 only had one seat (the Air Force’s SR-71 had two), but the modifications that turned the A-12 into the M-21 included the addition of a second seat, for the drone’s launch control officer. Lockheed eventually built two M-21s and thirty-eight D-21 drones.

Flight testing began in late 1964. At first, the idea was to see if the M-21 could even fly at high speeds with a drone riding piggyback. Satisfied that the awkward configuration would fly, they then moved on to launch testing in the spring of 1966. This was the scary part.

In Kelly Johnson’s record of the M-21/D-21 testing, he admitted that the separation was “the most dangerous maneuver we have ever been involved [with on] any airplane I have ever worked on.”

I’m sure the pilots felt awesome about that.

In fact, during the first actual separation flight, the drone was released from the mother ship and then just kinda hung in the air for a couple of seconds before it finally sped off. Yikes.

The second launch went a little smoother. On April 27, 1966, the D-21 separated from the mother ship and blasted off to Mach 3.3 and an altitude of ninety thousand feet. Awesome, right?! Well, no. After fourteen hundred miles the D-21 crashed due to a hydraulic pump failure.

But that’s why we test things. To iron out the kinks. To fix the bugs. To work out the problems we run into on test flights, and to try and predict (and prevent) other issues before they happen.

So on to the next one. The good news is that test number three had absolutely no hydraulic problems (fixed!). The aircraft was able to successfully complete the experimental mission’s entire 1,840-mile flight distance! It even was able to execute multiple preprogrammed turns. Nothing can stop us now!

Actually, never mind. The bad news is that an electronics failure prevented the camera system from releasing the film. It doesn’t do anyone any good if the drone flies straight, fast, and true, but then doesn’t do the one thing it was designed for in the first place: collect aerial intelligence. Well, I guess, to be fair, the drone did collect the intelligence, but it blew up before it was able to give it to us.

The fourth and final launch from the back of an M-21 was a heartbreaking disaster, so I’ll put my snark aside in deference to a brave pilot who gave the ultimate sacrifice for the security of his country. The July 30 test would be slightly different from the others. In the first three tests, the D-21 was detached from the mother ship while the M-21 was in a slight dive (0.9 g—nothing dramatic, but enough to play it safe and provide a better launch angle). The problem was, in real-world missions the crew might not have the opportunity to go into a dive to launch the drone. They might need to stay at altitude to avoid enemy fighters or SAMs. Johnson needed to know if the D-21 could successfully separate at level flight.