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The Cold War Plan to Build Earth's Largest Telescope

Sugar Grove,Cold War,Moon
Daniel Oberhaus
David Kramer
January 13, 20205:00 AM UTC (UTC +0)


Tucked away in the rolling foothills of the Allegheny Mountains, Sugar Grove, West Virginia is a picture-perfect small American town. Stroll down the tree-lined main street and you’ll find a daycare center and a bowling alley. A few blocks away there’s a gymnasium lined with pennants and a hobbyshop for woodworking. The houses have freshly painted clapboards and white picket fences. The town is textbook Americana—and for the last four years it’s been entirely deserted.

Sugar Grove didn’t always seem like it was plucked from a Twilight Zone episode. If you visited the town 50 years ago, you’d have found it to be a hive of activity. You see, Sugar Grove was always a military facility. It was built in the 1950s to house the families of soldiers working on a top secret project just up the road. Here, in a secluded clearing of dense national forest, Navy personnel were toiling away on what would have become the largest radio telescope ever built. At the time, the project was conceived as an unprecedented piece of intelligence infrastructure that would enlist the moon itself as an ally in the struggle against Soviet communism.  

Today, there is little evidence the Sugar Grove telescope ever existed. Most documents pertaining to its plans remain classified by the National Reconnaissance Office. As for the telescope itself, the only clues that construction ever began are a few steel struts rising from an anonymous concrete pad.

The story of the Sugar Grove radio telescope is the story of the largest telescope never built. It’s a story of massive policy failures and military hubris, of scientific complicity and engineering marvels. Ultimately, it’s the story of how the quest to control outer space nearly derailed our ability to understand it.  


It was a fine May day in 1940 and the 34-year-old Jack Dewitt was thinking about the moon. For the last eight years, Dewitt had served as the chief engineer at Nashville’s oldest radio station, WSM, where he wielded his uncanny knack for electrical engineering to help bring the twang of country music to a national audience. When Dewitt wasn’t tinkering with antennas and oscillators at the station, he could often be found indulging his other passion—astronomy. And on this particular day he hit upon a way to bring the two together.

“It has occurred to me that it might be possible to reflect ultra-short waves from the moon,” Dewitt wrote in his notebook. “So far as I know no one has ever sent waves off the earth and measured their return through the entire atmosphere. If this could be done it would open up wide possibilities for the study of the upper atmosphere. In addition, this may open up a new method of world communication.”

Dewitt sketched out a rough outline of what such a system might look like and some of the parameters that might make it possible. It was a revolutionary idea, but also, perhaps, a crazy one. He kept it to himself.

A year and a half later, the United States entered World War II and Dewitt enlisted in the Army. He quickly rose through its ranks and by 1943 took a position as the Director of the US Army’s Evans Signal Laboratory in Belmar, New Jersey. For the remainder of the war, Dewitt and his lab focused their energy on developing radar, a brand new method for identifying objects by observing the way they reflect radio waves. But the moon never left Dewitt’s mind. 

Following the Japanese surrender in 1945 and the freeing up of military resources, Dewitt finally had the opportunity he was waiting for. Together with four other engineers from the signal lab, he plotted how they might apply the principles of radar on a cosmic scale to bounce a radio signal off the moon. And so Project Diana was born, its name selected by Dewitt in homage to the Roman goddess of the moon. 

It can be difficult to appreciate just how wild this idea must have sounded when Dewitt pitched it to the Army. Today, moon bounces are well within the capabilities of radio amateurs and national space agencies regularly communicate with robots on the surface of Mars and beyond. But Dewitt and the boys at the Evans Signal Lab were the first ones to show this was possible.

By the end of 1945, Dewitt had crunched the numbers and built a radar system quite unlike any other. The lunar radar stood atop a 100-foot tower overlooking the Atlantic Ocean just down the way from the Shark River inlet near Neptune City, New Jersey. It was cobbled together from parts scavenged from other radars to create a sort of Frankenstein’s monster of electrical engineering. The important thing was that it worked, and according to Dewitt’s calculations, would be capable of generating and receiving a signal that could transverse the Earth’s ionosphere.  

The math checked out, but bringing the project to fruition proved more challenging than expected. Dewitt and his team spent weeks poking the moon with radio waves as soon as it would appear on the horizon, but they hadn’t heard so much as a peep in return. The equipment was finicky and their efforts may have been hampered by an as yet unknown phenomenon—the Faraday effect—which distorts radio signals as they pass through the ionosphere.

Then, on January 10, 1946, they made their breakthrough. It was a few minutes before noon and the moon had just appeared on the horizon. A few members from the Diana team, huddled together in a radio shack near the tower, pushed out their signal. Two-and-a-half seconds later, just as predicted, the cathode-ray screen in the control room lit up with a pulse and a speaker produced a corresponding beep.

The Project Diana team had just become the first to send a signal into space and receive an answer back. It was a historic moment, but in a testament to DeWitt’s estimation of the likelihood of success, he wasn’t even there to witness it. “I was over in Belmar having lunch and picking up some items like cigarettes at the drugstore,” he later recalled. Still he immediately grasped the implications of what he and his team had accomplished. Dewitt saw that the ability to retrieve radio signals from space opened up the solar system for human exploration—but the military had other ideas.


Around the same time that Dewitt was building his lunar radar at the Army’s signal laboratory, a young Navy electrical engineer named James Trexler was also preoccupied with the moon. Fresh out of Southern Methodist University where he had spent his time experimenting with reflecting radio waves off of meteor ionization trails, Trexler had joined the Navy Research Laboratory as a junior radio engineer and quickly rose through its ranks. Although most of Trexler’s day-to-day work involved refining military radar technology, he couldn’t help thinking bigger—much, much bigger.

In a notebook entry dated January 28, 1945, Trexler described a transcontinental communication system that would establish a radio link between Washington, DC and Los Angeles by bouncing the signal off the moon. Trexler did some back of the envelope calculations that showed how such a system might work, but he didn’t tell anyone about his idea for years. Instead, he focused on his work at the NRL, which was increasingly concerned with the phenomenon of so-called “anomalous signals.”

For decades, military receivers had been picking up seemingly random signals from all over the world. Under certain conditions, signals from Japan, Europe, and other far flung locales seemed to bounce off the ionosphere and reflect back toward Earth. In 1947, an NRL radio engineer named Howard Lorenzen called Trexler into his office to float a “rather interesting” idea: What if they built a system that could intercept anomalous radio signals as a form of intelligence gathering? 

So Lorenzen and Trexler cobbled together a receiver from old Nazi antennas the NRL had lying around from the war, and began running experiments at the NRL Blue Plains site near Washington. Their primary objective was to determine the direction of anomalous radio waves. The project was chugging along until June 1948, when Trexler happened to read a paper published by three researchers working in a corporate communications laboratory run by International Telephone and Telegraph. The researchers hypothesized that the moon might have an ionosphere, which would reflect certain radio wavelengths back toward Earth with much higher fidelity than bouncing them off the surface. 

Trexler immediately grasped its implications for his own work. Rather than searching for the directions of random signals bouncing off the ionosphere, the Navy could enlist the moon itself to eavesdrop on Soviet communications and intercept radar signals. It would be like having a big ear in the sky. 

Within a few days of reading the paper, Trexler had calculated that trying to intercept signals bounced off the moon was both feasible and desirable. His bosses at NRL agreed and so Trexler and Lorenzen built a couple of experimental antennas at Blue Plains in the hopes of detecting Soviet radar signals reflected off the moon. The project—codenamed “Joe” in honor of Joseph Stalin—consumed the pair for the next two years.



Early successes with the scrappy antennas at Blue Plains demonstrated to the NRL that the project had a lot of potential as an intelligence platform. In 1950, the Navy allotted the project enough funding to build a new radar at Stump Neck, Maryland and christened it with a new name: the Passive Moon Relay or PAMOR. The project’s new dish was built directly into the Earth and was oriented to maximize observations in the direction of the Soviet Union. It briefly held the distinction of being the largest parabolic radio dish in the world, a testament to the Navy’s enthusiasm for the project. 

The Navy maintained utmost secrecy about the purposes of its new radar. PAMOR was top secret, but when the dish wasn’t used for military observations it was passed off to astronomers. This proved to be an effective cover for the project, and marked the beginning of a close relationship between Trexler’s intelligence unit and the astronomical community.

The Stump Neck telescope allowed Trexler and Lorenzen to scale up their efforts at detecting Soviet signals with the moon, but it was a chance event in October 1951 that really captured the Navy’s attention. That day, Trexler and Lorenzen decided to send some short radio pulses toward the moon and listen for a response. When they heard back, everyone working on PAMOR was surprised by the quality of the reflection. It got the group thinking—in addition to using the moon for passive surveillance, perhaps it could also be used as a secure communication channel. No matter what happened on Earth—war, electromagnetic storms, whatever—the moon could always be used to send a signal around the globe even if all the telecommunications infrastructure was destroyed. 

And so the Communication Moon Relay project was born. Unlike PAMOR, which remained top secret, CMR was unclassified and a point of pride for the military. It envisioned using the moon for all sorts of things like communicating with aircraft and submarines, or broadcasting public messages to half the world at a time. On July 24, 1954, after years of experiments transmitting toward the moon, Trexler sat down at a microphone and delivered a short monologue into a microphone. There are no records of what was said, but two-and-a-half seconds later a speaker in the room echoed his message back to him.

It was the first time in history that a human voice left the planet and returned again.


But using the moon to talk to yourself didn’t have much utility for the military. The real prize would be sending a message between two distant locations using the moon as a relay. Only a few months after Trexler’s historic transmission, the Navy made it happen. On November 29, 1954, Franz Kurie, the associate director of the NRL and one of the inventors of radar, sent a message from Stump Neck to his colleagues on the West Coast. His message was simple: “Lift up your eyes and behold a new horizon.”

The Navy was, understandably, ecstatic about their new toy. No longer was CMR just a curiosity; now it was a bonafide part of military communication infrastructure. The Navy had conscripted the moon. Following Kurie’s broadcast, the Navy leaned into the project and began developing communication systems that could be deployed on warships and receive lunar messages. The NRL doubled down on its efforts to boost the power of its transmitters and sensitivity of its receivers.

The existence of CMR was revealed to the world in 1960. A photo transmitted from the USS Hancock, to Washington, DC, featured sailors arranged on the deck of the aircraft in order to spell out two words: “MOON RELAY.” The stunt generated a lot of publicity, but by then the military was on to bigger things. The Soviet Union had stunned the world when it launched Sputnik in 1957, and it didn’t take the Navy long to realize the future of communication was artificial satellites, not moon bounces.

The premature death of the CMR project might have been a blow to Trexler and Lorenzen had they not been so preoccupied with other problems. As the Navy operationalized the moon bounce system, the pair had resumed work on PAMOR at Stump Neck. But after some early successes, it became clear that intercepting Soviet radar signals would require a bigger antenna—a lot bigger.




Shortly after he spoke to the moon, Trexler began lobbying the Navy for a giant, steerable telescope. If they wanted to listen to the Soviets, then Trexler calculated they would need a dish at least 700 feet in diameter. To get an understanding of just how impractical Trexler’s pitch must have sounded, one needs to consider that the largest radio telescope in the world, under construction at the time, was only 250 feet in diameter. To this day, the largest steerable radio telescope in the world is only 300 feet. Trexler’s request was simply unreasonable—and everyone knew it.

But Trexler wasn’t one to let a little bureaucratic adversity get in his way; he had convinced the Navy to talk to the moon, after all. If the promise of eavesdropping on the Soviets wasn’t enough to convince the Navy to cough up the funds for his massive telescope, Trexler knew he could find an ally in the NRL astronomy department, which had been clamoring for a big dish for years 

Starting in 1954, the NRL astronomers and Trexler’s signals intelligence people started meeting to discuss the details of what the project would look like. The basic idea was this: the signals intelligence people would get priority use of the device for eavesdropping on the Soviets when the moon was in view, and the rest of the time astronomers could use it to study the stars. But what the groups couldn’t agree on was just how big this thing should be. The stargazers pushed for a more modest telescope that was only 500 feet in diameter, but Trexler insisted this would be insufficient for his needs. So after months of back and forth, they finally struck a compromise—the telescope would be 600 feet in diameter.

Once they had hashed out the details of the project, now called the Naval Research Radio Facility or NRRO, this unlikely alliance of astronomers and spies started making the rounds to sell their project to a government and public who would ultimately be paying for it. The scientists handled the public, explaining how the telescope could be used to unravel the mysteries of the universe, and downplaying its covert military purposes as much as possible. Meanwhile, Trexler pitched the Navy on the idea, explaining how it could be used for everything from intercepting Soviet radar to a powerful new communication tool for the Navy’s global fleet. After months of campaigning, the Navy bought Trexler’s pitch and the NRL team started drilling into the engineering details for what would be far and away the biggest telescope ever built.

Even on paper, the NRRO was a beast. It’s 600 foot dish was to be mounted on top of a stubby rolling platform that would give it a 360-degree field of view. The telescope could be pointed in any direction between the horizons to an accuracy of only a fraction of a degree. The whole apparatus would weigh over 22,000 tons, about the weight of a freight ship, and stand taller than the Washington monument. It would be the largest, land-based moveable structure ever created by a long shot. There’s no other way to say it: the thing was fucking huge.  

The Navy broke ground for the telescope in Sugar Grove, West Virginia in June 1958—and that’s precisely when the problems started. The tensions of the Cold War had endowed the NRRO project with a sense of urgency, which meant that the telescope’s engineers did not have time to finalize their designs before construction started. The NRL made a “strategic” decision to build and design the telescope at the same time, which turned out to be a very, very expensive mistake. Flaws in the initial designs meant that engineers were constantly adding more material to the support structure for the giant dish. Each new steel beam in the design added thousands of dollars to the cost of the project and the price estimate for the telescope quickly ballooned.

Originally pitched as a $20 million project, by 1959 the telescope was estimated to cost around $79 million. It was way over budget, but the Navy wanted this telescope and it wanted it bad. This much was clear to the planetary astronomer Frank Drake, who visited the Sugar Grove facility about a year after construction began. He was working at the National Radio Astronomy Observatory, which is located about an hour drive over the Allegheny mountains in Green Bank, West Virginia. The Navy had invited Drake and his colleagues at NRAO to check out the progress on its world class telescope as a good will gesture, and the visitors were amazed at what they saw.

As Drake later detailed in an essay posted to the SETI League mailing list, he walked through the town that was home to the electrical engineers working on the telescope and found that there were “countless coffee mugs and t-shirts with an artist’s conception of the telescope on them and souvenirs of all kinds.” Drake wandered around the “huge structural components” for the telescope that littered the area and found massive support towers, each 300-feet high, already in place beneath the telescope’s concrete base.  Beneath the base, he found a two-story building to be used by a small army of linguists, that would translate intercepted Soviet messages. The subterranean complex came complete with a shop, a technical library and lounge areas for the workers.

“Picture a beehive of little rooms, all underground, protected from radio frequency interference by overhead imported charcoal and soil,” Drake recalled. “The whole thing seemed like something out of a science fiction movie.”

But the NRRO was not long for this world. Frequent design changes pushed the budget higher and higher. In an attempt to limit the telescope’s runaway expenses, Congress passed a law in 1961 that capped the budget at $135 million. By that point, however, everyone involved with Sugar Grove knew the project was doomed. There was no way to complete the telescope with that sort of budget, and it seemed to be a matter of time until the whole thing was canceled outright. By 1961, construction on the telescope had come to a crawl and efforts were shifted almost entirely to design work. The following year the Secretary of Defense made a final judgment call: The world’s biggest dish was getting eighty-sixed.

“The government of West Virginia was devastated,” Drake later eulogized. “All those coffee cups and t-shirts wasted.”



By the time the Navy pulled the plug on the NRRO, it had already spent $42 million and the final cost of the project was estimated to be between $200 and $300 million—equivalent to nearly $2 billion today. Still, the Department of Defense denied that massive cost overruns were the sole or even the main reason for the telescope’s demise. In a statement provided to Congress in 1962, the Navy claimed that “major advances in science and technology not foreseen when the project was first established have reached the stage where many functions of the project can now be achieved at less cost by other means.”

The Navy was referring to artificial satellites, which it had already begun deploying on reconnaissance missions. (Indeed, the first spy satellites, codenamed Galactic Radiation and Background or GRAB, were designed with Trexler’s help and used to study Soviet radar installations.) Still, Congress wanted some answers—and maybe a few heads—so it called for a formal inquiry into what went wrong at Sugar Grove on August 11, just three weeks after the Navy killed the project.  

“It is important, I believe, that our government try to learn from every experience of this nature as much as can be learned; thereby we may avoid repeating mistakes in the future,” democratic senator Hubert Humphrey, a longtime critic of the project, told Congress. “The Navy has pointed out that some valuable and useful findings did emerge from the project, but one would have to wear rose-colored glasses to fail to see the enormous loss involved.”

As Humphrey noted, it wasn’t just the taxpayers’ money that had been wasted during the lifespan of the Sugar Grove project. Arguably more important, it monopolized the time of legions of America’s brightest scientific minds who “have now seen much of their efforts, unfortunately, go down the drain.” He identified several main causes of the Sugar Grove fiasco: the Navy ignored technological developments that would render the telescope obsolete like artificial satellites; the Navy grossly underestimated the cost of the telescope; the Navy designed and built the telescope concurrently; and the Navy ignored Congress’ concerns about the telescope’s problems.  

“Research is, by definition, a venture into the unknown and Sugar Grove involved unprecedented scientific and engineering problems,” Humphrey said.

“Congress does not seek infallibility. It does seek and have a right to expect candor and good judgment.”


Humphrey’s testimony was damning and launched a formal investigation into the Sugar Grove fiasco that was published two years later. It arrived at essentially the same conclusions, but was backed by hard numbers and expert witnesses. By that point, however, the damage had been done. The Sugar Grove debacle had cast a shadow over American radio astronomy throughout its development and would leave a stain on proposed telescope projects for years to come.

Official schematics and rendering of the proposed telescope.

Shortly after Humphrey’s speech to the Senate, the House of Representatives convened a hearing on the future of American radio astronomy in September 1962. As the science historian Andrew Butrica notes in To See the Unseen: A History of Planetary Radar Astronomy, “the Sugar Grove fiasco motivated the hearings, at which radio astronomers defended their telescope projects. The National Science Foundation was on center stage as the primary civilian funding agency for radio astronomy, and all design concepts and funding requests had to deal with the omnipresent wake of the Sugar Grove disaster. The future of large radio and radar dishes seemed precarious.”

By this point, the American astronomy community was already starting to lean into the idea of using large radio telescope arrays, in which a number of small dishes act like one big dish, instead of large parabolic dishes. Arrays offered some scientific and engineering advantages, but perhaps most importantly they weren’t marred by the failure of giant parabolic dishes like the one at Sugar Grove. Following the House hearing on radio astronomy, the National Academy of Sciences convened a panel chaired by the astronomer Albert Whitford, to plot the future of radio and optical telescopes in the US.

In late November 1963, Whitford assembled a crack team of astronomers to discuss the tradeoffs of large parabolic dishes versus arrays. Their deliberations were subsequently published as the Whitford Report, which furnished several recommendations for next generation radio telescopes. Interestingly enough, the Whitford report didn’t condemn large parabolic radio dishes outright. In fact, it called for two 300-foot steerable dishes to be built and a study to examine the largest possible steerable radio dish.

By the time the Whitford report was published, the National Radio Astronomy Observatory had already built its massive 300-foot radio telescope at Green Bank. When it came online in 1962 with Frank Drake at the controls, it was the largest moveable telescope in the world— but it was short lived. The telescope collapsed in 1988 due to stress fractures in the structure. But a decade later Green Bank was once again home to a 328-foot telescope, which remains the largest fully steerable telescope to this day.

In the meantime, the astronomy community has largely embraced radio telescope arrays for its scientific needs. Although arrays are complex in their own right, they typically are cheaper and involve less structural engineering wizardry. There are still cases where large parabolic dishes are advantageous and Ken Kellerman, a senior scientist at NRAO, says scientists are beating a path to their door to request time on its telescopes. But after Sugar Grove, no government has ever been foolhardy enough to push steerable parabolic dishes beyond diameters of about 300-feet. It seems a 600-foot scope is doomed to remain engineering’s white whale.

Just down the road from Green Bank, the town of Sugar Grove is still standing, but reveals little about its secretive past. In 2016, the government auctioned off the town and it sold for $11.2 million to a real estate developer. The plan is to turn Sugar Grove into a retirement home for veterans. As for the telescope site itself, you can still see a few lonely struts protruding from its massive concrete foundation using Google Maps. I suppose you could try to visit this monument to military hubris, but you probably wouldn’t get very far. The site is currently occupied by the National Security Agency, which has installed its own antennas for classified surveillance purposes under the codename Timberline. We may never know who—or what—they’re listening to, but you can bet it’s not the moon.

Special thanks to Ken Kellermann at NRAO/Green Bank for his help on this piece

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Daniel Oberhaus
David Kramer
January 13, 20205:00 AM UTC (UTC +0)