The A-12, which would evolve into the SR-71, would beat Soviet advances in radar technology in three fields, Annie Jacobsen explains (in Area 51), height, speed, and stealth:
The airplane needed to fly at ninety thousand feet and at a remarkably unprecedented speed of twenty-three hundred miles per hour, or Mach 3. In the late 1950s, for an aircraft to leave the tarmac on its own power and sustain even Mach 2 flight was unheard-of. Speed offered cover. In the event that a Mach 3 aircraft was tracked by radar, that kind of speed would make it extremely difficult to shoot down. By comparison, a U-2, which flew around five hundred miles per hour, would be seen by a Soviet SA-2 missile system approximately ten minutes before it was in shoot-down range, where it would remain for a full five minutes. An aircraft traveling at Mach 3 would be seen by Soviet radar for fewer than a hundred and twenty seconds before it could be fired upon, and it would remain in target range for fewer than twenty seconds. After that twenty-second window closed, the airplane would be too close for a Soviet missile to fire on it. The missile couldn’t chase the airplane because, even though the top speed for a missile at the time was Mach 3.5, once a missile gets that far into the upper atmosphere, it loses precision and speed. Shooting down an airplane flying at three times the speed of sound at ninety thousand feet was equivalent to hitting a bullet whizzing by seventeen miles away with another bullet.
Stealth was still a very new technology:
“Radar works analogous to a bat,” Lovick explains. “The bat squeaks and the sound hits a bug. The squeak gets sent back to the bat and the bat measures time and distance to the bug through the echo it receives.” So how does one get the bug to absorb the squeak? “The way in which to solve the radar problem for us at Lockheed was to create a surface that would redirect radar returns. We needed to send them off in a direction other than back at the Soviet radars. We could also do this by absorbing radar returns, like a diaper absorbs liquid. In theory it was simple. But it turned out to be quite a complicated problem to solve.”
Lovick had been solving problems ever since he was a child growing up in Falls City, Nebraska, during the Depression—for instance, the time he wanted to learn to play the piano but did not want to disturb his family while he practiced. “I took the piano apart and reconfigured its parts to suppress the sound. Then I sent the vibrations from the strings electronically through a small amplifier to a headset I wore.” This was hardly something most fourteen-year-old children were doing in 1933. Four years later, at the age of eighteen, Lovick published his first article on radar, for Radio-Craft magazine. Inspired to think he might have a career in radar technology, he wrote to Lockheed Corporation in faraway California asking for a job. Lockheed turned him down. So he took a minimum-wage job as a radio repairman at a local Montgomery Ward, something that, at the age of ninety-one, he still considers a serendipitous career move. “What I learned at Montgomery Ward, in an employment capacity that today some might perceive as a dead-end job, would later play an important role in my future spy plane career.” Namely, that there is as much to learn from what doesn’t work as from what does.
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“An anechoic chamber is an enclosed space covered in energy-absorbing materials, the by-product of which is noiselessness,” Lovick explains. It is so quiet inside the chamber that if a person stands alone inside its four walls, he can hear the blood flowing inside his body. “Particularly loud is the blood in one’s head,” Lovick notes. Only in such a strictly controlled environment could the physicist and his team accurately test how a one-twentieth-scale model would react to radar beams aimed at it. Lockheed’s wood shop built tiny airplane models for the physicists, not unlike the models kids play with. Lovick and the team painstakingly applied radar-absorbing material to the models then strung them up in the anechoic chamber to test. Based on the radar echo results, the shape and design of the spy plane would change. So would its name. Over the next several months, the design numbers for the Archangel-1 went up incrementally, through eleven major changes. This is why the final and official Agency designation for the airplane was Archangel-12, or A-12 for short.
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With the plane’s underbelly now flat, its radar cross section was reduced by an astonishing 90 percent.
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“On 31 March we started to build a full scale mockup and elevation device to raise the mockup 50 feet in the air for radar tests,” Johnson wrote in documents declassified in July 2007. What Johnson was imagining in this “elevation device” would eventually become the legendary Area 51 pylon, or radar test pole.
Lockheed engineers brought with them a mock-up of the aircraft so detailed that it could easily be mistaken for the real thing. For accurate radar results, the model had to represent everything the real aircraft would be, from the size of the rivets to the slope on the chines. It had taken more than four months to build. When it was done, the wooden airplane, with its 102-foot-long fuselage and 55-foot-long wooden wings, was packed up in a wooden crate in preparation for its journey out to Area 51. Getting it there was a daunting task, and the road from Burbank to Area 51 needed to be prepared in advance. The transport crate had been disguised to look like a generic wide load, but the size made it considerably wider than wide. Crews were dispatched before the trip to remove obstructing road signs and to trim overhanging trees. In a few places along the highway, the road had to be made level.
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Each member of Lovick’s crew carried in his pocket a small chart indicating Soviet satellite schedules. This often meant working odd hours, including at night. “It also made for a lot of technicians running around,” Lovick explains. “Satellites passed overhead often. Getting an aircraft up on the radar test pole took eighteen minutes. It took another eighteen minutes to get it back down. That left only a set amount of time to shoot radar at it and take data recordings.” As soon as technicians were done, they took the aircraft down and whisked it away into its hangar.
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At night, workers needed to bundle up in heavy coats and wool hats. But during the day, temperatures could reach 120 degrees. “Once, I saw a coyote chasing a rabbit and they were both walking,” Lovick recalls.
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Bissell had been informed that Lockheed’s A-12 would appear on enemy radar as bigger than a bird but smaller than a man. But he had not yet been told about a problem in the aircraft’s low observables that Lovick and the team had been unable to remedy while testing the mock-up out at Area 51. Lovick explains: “The exhaust ducts from the two huge jet engines that powered the aircraft were proving impossible to make stealthy. Obviously, we couldn’t cover the openings with camouflage coating. During testing, the radar waves would go into the spaces where the engines would be, echo around, and come out like water being sprayed into a can. We’d tried screens and metallic grating. Nothing worked.”
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There in the conference room, Edward Lovick decided to speak up about an idea he had been considering for decades, “and that was how to ionize gas,” he says, referring to the scientific process by which the electrical charge of an atom is fundamentally changed. “I suggested that by adding the chemical compound cesium to the fuel, the exhaust would be ionized, likely masking it from radar. I had suggested cesium would be the best source of free electrons because, in the gaseous state, it would be the easiest to ionize.” If this complicated ionization worked—and Lovick believed it would—the results would be like putting a sponge in a can and running a hose into it. Instead of being bounced back, the radar return from the engines would be absorbed. “Bissell loved the idea,” says Lovick, adding that the suggestion was endorsed heartily by several of the customer’s consultants. An enthusiastic discussion ensued among the president’s science advisers, whom Lovick sensed had very little understanding of what it was he was proposing. In the end, the results would be up to Lovick to determine; later, his theory indeed proved correct. Those results remain a key component of stealth and are still classified as of 2011.
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Lockheed kept the contract. Lovick got a huge Christmas bonus, and the A-12 got a code name, Oxcart. It was ironic, an oxcart being one of the slowest vehicles on Earth and the Oxcart being the fastest.
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The aircraft was going to be five times faster than the U-2 and would fly a full three miles higher than the U-2.