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.

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.