On the evening of November 20, 2014, Bobby Livingston, the executive vice president of RR Auction, was working late. The Boston auction house, a boutique firm that focused in part on objects that had been flown into space, was hosting one of its regular seven p.m. sales. Lot 477, an innocent-looking envelope with several inked notary circles and three stamps, and emblazoned with the vibrant Emilio Pucci–designed insignia of the Apollo 15 mission, had a minimum bid of $1,000 on it.

As the clock ticked to the hour, the lot opened and, all around the world, the race was on. “The bidding started flying,” Livingston remembers. “It’s just very exciting to see these online bids come in.” As the system pushed bids higher in increments of 10 percent, Livingston watched the price rise in leaps and bounds. “When you start getting into numbers like 20,000, now it’s 22,000, then 26,000, 33,000, and 40, and it just goes up, whenever something gets in the mid–five figures, it’s pretty exciting. When something rare comes on the market and two people want it, you never know what’s going to happen,” he says.

Far away from the auction house, in the wee hours in London and the early morning of Australia, two alpha bidders were fighting madly, not just over an envelope that had made the journey to the Moon and returned safely to Earth, but over a physical manifestation of one of the biggest scandals ever to rock NASA and the Apollo space program.

The rare Sieger postal cover that went to the Moon and back with Apollo 15. It’s inscribed with the words “Landed at Hadley Moon, July 30, 1971” and signed by astronauts David R. Scott, Alfred M. Worden, and James B. Irwin. On the back is certification that it was “onboard the Falcon at the Hadley-Apennine Moon.”

When the dust settled, the Apollo 15 envelope had sold for $55,654.20, roughly four times what similar envelopes usually earned. An Australian collector had paid a world-record price for 1 of only 100 scandal-ridden “Sieger covers.”

This week, two of the biggest auction houses in the world, Sotheby’s and Christie’s, will host space-exploration sales to celebrate the 50th anniversary of the Apollo 11 Moon landing. The commemorative year is expected to push the booming space market to new heights.

But the monetization of the Apollo program was not always so acceptable.

A half-century before one sold for $55,000 at an auction in 2014, the scandalous Sieger covers cost three NASA astronauts their careers.

Mission: Send Stamps into Outer Space

On the morning of July 16, 1969, as the Mission Control Center hummed to life in preparation for the launch of Apollo 11 and the historic Moon landing that would be watched by an estimated 600 million people worldwide, two German civilians met on a shuttle bus bound for Cape Kennedy from Cocoa Beach, Florida.

It was not so unlikely that Hermann Walter Sieger would run into a fellow German national on the NASA bus. Sieger, owner of one of the biggest stamp companies in Germany, had many German friends among the scientists at NASA—former rocket experts who had expatriated to the United States after World War II. Sieger had traveled all the way from the Rhine Valley river town of Lorch to see the historic launch. “He was totally space-minded,” says his son Gunter Sieger. “He has hundreds of books about the exploration of space. He was a real fan of the whole Apollo project.”

As the shuttle headed for the V.I.P. stands, Sieger’s new friend, Horst Eiermann, explained that he worked for an aerospace-engineering company that had helped NASA with the Apollo program itself. Sieger, who was not able to be interviewed for this article but transcribed his experience in a 1973 essay, told Eiermann that he was attending the launch, not only to feed his own space enthusiasm but to fulfill the massive scope of Apollo 11 launch souvenirs he had prepared for his stamp-collecting customers: 90,000 mementos in all.

“This number obviously impressed [Eiermann], big even by American standards and probably significantly bigger than what companies occupied with printing souvenir envelopes for launches and landings usually stamp,” Sieger recalled in 1973.

Hermann Sieger’s clients were a global community of philatelists who had grown up in the early days of travel and had a particular passion for stamps with ties to exotic locales. Collectible souvenir airmail had flown with Amelia Earhart and Charles Lindbergh. “People were interested in buying stamps where you cannot go. It’s something of the fantasy,” says Gunter Sieger.

Now the ultimate travel fantasy was the Moon.

At home in Germany, Sieger had 140 employees and a roaring customer appetite for more objects that had scraped the surface of the stratosphere. So far, the only way to get one was to try to track down an astronaut’s address and send a fan letter, hoping he’d be willing to add your envelope to the Personal Preference Kit (P.P.K.) of private mementos, which astronauts were allowed to take into space, and then send the souvenir back. Sieger saw a business opportunity. He dreamed of tapping a market that hadn’t yet taken shape, and supplying a product that was impossible to find anywhere else on earth. The most valuable envelope he could offer his clients, he told Eiermann during the bus ride, as tents pitched to observe the launch flashed by, would be one that had actually gone to the Moon.

Jewelry, Golf Balls, and a Bottle of Scotch

The idea of bringing personal objects into space was not a new one. Astronauts had carted medallions, charms, jewelry, and paper currency to the Moon. Alan Shepard had packed two golf balls on Apollo 14 and a Bible had been brought up on the same trip. Wally Schirra’s team had sneaked a bottle of scotch into his ship. And in the only instance where an astronaut had been reprimanded, a Gemini astronaut brought a corned-beef sandwich onboard to eat later.

For the most part, the objects carried were favors for the flight crew—in the past, they’d included wedding rings, crosses, cuff links, Boy Scout patches. “They were generally modest, almost worthless trinkets, other than their journey into space,” recalled Apollo 15 astronaut Alfred Worden in his autobiography, Falling to Earth. “Receiving one was a sign you were in some kind of inner circle, with all the unspoken understanding and obligation not to embarrass the giver.”

Each item in this hodgepodge had to be disclosed to the chief of the astronaut office, “Deke” Slayton, to make sure it fit the weight requirements—lighter than a cereal box—and then tucked into a kit bag made of the same fire-resistant Beta cloth that covered space suits. Could a packet of souvenir envelopes be slipped into one of the astronaut’s kits?, Sieger wondered.

“You have to understand,” RR Auction’s Bobby Livingston says, “this wasn’t something unknown to other crews. All the astronauts have covers from their missions of some type that they took into space.” On top of delivering postal covers to space as one-off favors to fans and space wonks, a grisly tradition had developed among space crews of bringing along a few extra envelopes, called “insurance covers.” Because it was nearly impossible for astronauts to get life insurance once a Saturn V rocket showed up in their background checks, these valuable souvenirs, bearing stamps, seals, and signatures, rested quietly in the command module, acting as unofficial insurance policies for an astronaut’s family, were any one of the astronauts to die on the surface of the Moon or on re-entry back to Earth. “So,” explains Livingston, “when the German stamp dealer approaches Apollo 15, it’s not out of the blue.”

Astronaut James B. Irwin on the Moon, 1971.

It took four more Apollo missions to fish out a crew who would sign on to the deal. With Eiermann acting as the middleman, the three astronauts—Colonel David Scott, Major Alfred Worden, and Lieutenant Colonel James Irwin—scheduled for the upcoming 1971 Apollo 15 mission each agreed to a fee of $7,000 to be deposited in a German bank in return for bringing a cache of 100 postal covers with them to the Moon and returning them safely to Earth. It was a sizable amount given that the Apollo 11 astronauts had landed on the Moon two years earlier on annual salaries of $17,000 to $31,000. The envelopes were prepared and, on July 26, 1971, at 9:34 a.m., blasted off with the astronauts into the inky blackness of space.

The 100 Sieger envelopes that orbited the Moon were not alone. In total, 632 items made it into various P.P.K. bags and pockets. But the 100 Sieger envelopes had no manifest record of their existence. Resting atop this pile were two official U.S.P.S. stamps. On August 2, 1971, Mission Commander Dave Scott reached into the lunar rover and, on live TV before millions of viewers, postmarked the stamp to prove that the U.S. delivered mail anywhere in the universe. “I’m very proud to have the opportunity here to play postman,” he announced.

Whether they were in the pocket of Scott’s space suit or back in the lunar module parked nearby, the Sieger envelopes had made it to the surface of the Moon.

From the Moon to Mister Rogers

Sieger waited anxiously as the astronauts returned to Earth and the packet of letters was delivered, first to Eiermann in Stuttgart, then to the Sieger company in the fairy-tale hills and castles of Lorch. “He was very, very, very nervous,” remembers Sieger’s son, who was home from boarding school for the summer holidays. “Nowadays, I would look for personal delivery.” At one point, the mailman left the precious parcel on the middleman’s garden wall for pickup. “The funny thing is that the most dangerous part of the journey of these moon letters wasn’t in space,” Sieger later said.

The astronauts had completed a $445 million flight, becoming the seventh and eighth men to walk on the Moon. Using the lunar rover, they covered far more distance than previous explorers. Where past missions had focused on “firsts” and exploration, Apollo 15 was the scientists’ mission—chock-full of laser, seismographic, and geologic experiments. “Scientists working on the mission expressed elation over the accomplishments of Apollo 15,” confirmed The New York Times. Back in America, where an unpopular war raged on, the public’s enthusiasm for the space program was lower than during the buoyant days of Apollo 11. But many still saw the mission as a powerful global endeavor. “In the midst of all the human tragedy, it is some relief to contemplate the voyage of the astronauts in the Apollo-15,” India’s prime minister, Indira Gandhi, wrote to President Nixon. “These valiant men and the team of scientists supporting them represent manʼs eternal longing to break from the constraints of time and space.”

The Apollo 15 crew settled into the life of homecoming heroes. They were treated to a weekend at Camp David, dined with mayors and celebrities, and exchanged messages with the Pope. Astronaut Al Worden even visited Mister Rogers’ Neighborhood to make a special delivery. “I brought something back with me that you and I looked at and discussed before my flight, and I thought you’d like to have it back just as I promised,” Worden told Fred Rogers, pulling an envelope out of his pocket.

Rogers read the inscription aloud: “This envelope with children’s questions was carried to the Moon on Apollo 15 for Mister Rogers’ Neighborhood.” Then he showed the cameras the simple cover with the TV show’s colorful logo in the return-address corner.

“I actually carried that with me,” said Worden.

“You promised that you would and I’m mighty glad to have it,” said Rogers.

Similarly delighted to have his envelopes, Sieger notified the people on his high-end private subscription list, and, in a few days, the envelopes were all gone, selling for $1,330 each, roughly the price of a Volkswagen.

A Visit from the F.B.I.

Whether Sieger reneged on a secrecy deal to keep quiet until the astronauts retired, or whether that part of the agreement did not reach him through the middleman, the cover story broke. As news surfaced on the international market, the horrified Apollo 15 astronauts, fearing for their careers, did everything they could to unwind the agreement. But it was too late. NASA had caught wind of the Sieger deal as well as some 300 similarly suspicious covers that the astronauts had supplemented their kits with. TV reporters, tabloids, and the F.B.I. showed up at Sieger’s door, according to Sieger’s son. The Apollo crew received an official reprimand—the only one at that point from NASA, apart from the one regarding that corned-beef sandwich that had gone on a Gemini mission. (Worden was not available for comment, Scott did not respond to requests for comment, and Irwin passed away in 1991.)

“Astronauts are under extreme stress in the months preceding a flight to the Moon and their poor judgment in carrying the unauthorized covers must be considered in this light. Nonetheless, NASA cannot condone these actions,” said NASA’s deputy administrator, Dr. George Low. He assured the press that the astronauts had refused the $8,360 that had been added to German bank accounts in each of their names. “The only thing missing,” said The New York Times, “was a small, tearful, dirty‐faced boy in the hall, crying, ‘Say it ain’t so, Dave, say it ain’t so.’”

The Apollo 15 astronauts were not the first ones to make a bit of extra money on a Moon landing. “We have recently learned from NASA that 15 astronauts (nine of them still with NASA) collected a total of $37,500 by autographing blocks of stamps, postcards and other souvenirs for sale,” The New York Times reported in 1972.

But the days of quiet cover-ups were over. The Watergate scandal was heating up and government agencies had zero tolerance for anything that would tarnish their reputation, particularly one built on the appearance of generations of Eagle Scout, Norman Rockwell–pure American astronauts. The manned Apollo space program was on its final two missions. In short, NASA wasn’t open to any bad P.R. Congress launched an investigation into the “commercialization of items carried by astronauts” and why government employees had come so close to profiting off of a taxpayer program. “The poor Apollo 15 crew gets skewered,” says Livingston. “It was a raw deal, what they put these astronauts through.”

The Apollo 15 astronauts never flew again.

Sieger had half-heartedly tried to re-gather the portfolio. But by the time he had gotten word, he explained, the stamps were already gone—not mentioning one he kept as a souvenir in his office, or two that had been returned and immediately resold. “We understand that Sieger is interested in buying back any of the stamps he can,” a NASA spokesman told The New York Times. But Sieger had no luck. “For some reason,” the spokesperson told the Times, “they have been going up in value.”

Early astronauts—because they were either sentimental or pack rats—had grabbed joysticks and manuals out of lunar modules before they were jettisoned. Now NASA clamped down on anything that might be sold for profit and set up a fence around anything that might be called government property. “If you mentioned the word ‘cover,’ people would look over their shoulder to see if anyone was listening,” says collector Howard Weinberger, who provides freelance-consulting services for private buyers.

Early astronauts had grabbed joysticks and manuals out of lunar modules before they were jettisoned. Now NASA clamped down on anything that might be sold for profit.

As NASA tried to forget the episode of the Sieger stamps, philatelists became only more obsessed. “Because there was all this backlash, they’re now as famous as, say, the Apollo 11 flown covers,” says Gary Piattoni, an appraiser (and a frequent expert on Antiques Roadshow). “It’s forbidden fruit. Collectors just love that…. The blowback from the press is really what made these things famous. It’s just like the Mona Lisa. The Mona Lisa is only famous because it was stolen. It’s all P.R.”

For years, Bobby Livingston watched a niche group of collectors come to his auctions. Then, 15 to 20 years ago, something started to shift. A wave of tech entrepreneurs, engineers, and programmers who had watched the space transmissions on television as kids and been inspired to get into technology were coming back to their roots. And they came to buy.

“The tech guys are out-moneying and outbidding the smaller, earlier collectors, who were just regular stamp collectors,” says Piattoni. “These are people who have so much money that they just play with it.”

At the same time, the surprise appearance, and $388,375 auction, of an Apollo 13 checklist led NASA to confiscate the artifact. But collectors and astronauts, now in their later years, protested. “[NASA] said, ‘If you can get an act of Congress to authorize your claim, we’ll give it back,’” remembers Weinberger. Within a matter of months, President Obama had signed “full ownership rights” of objects carried on space missions over to the Gemini, Mercury, and Apollo astronauts. Anything astronauts carried to the Moon now belonged to them.

At Auction Houses, the Space Market Is Booming

Now, with the 50th anniversary of the Apollo 11 landing this weekend, the space market is booming. “Anything that went to the Moon or belonged to an astronaut is extremely hot market growth,” says Livingston. “We’re seeing prices that we never expected to see.” Anything from the private collection of an astronaut is gold.

Sotheby’s and Christie’s got in on the action, alongside boutique auction houses such as RR Auction. “They have thousands of people now, and it’s feeding on itself,” says Weinberger. As a consultant who also spent 20 years as a portfolio manager, Weinberger is hearing terms that aren’t traditionally tied to the collectibles market—terms like “investment” and “future worth.”

“They’re realizing that great historic rarities, whether it be antiques, art, booze, space memorabilia, coins, documents, there’s not a lot of it and these things are great things and worthy of a place in a portfolio,” he says.

Piattoni takes a more cautious approach to artifact investment. “They say the worst place to have your money in collectibles is wine, watches, cars. When the market drops, those markets collapse immediately. They dry up,” he says. “Maybe the next one will be watches, wine, and space memorabilia.”

The Apollo 15 Lunar Roving Vehicle undergoes compatibility fit​ checks with the lunar module at the Kennedy Space Cente​r on May 3, 1971. Save some space for the stamps!

Gunter Sieger believes the Apollo 15 stamp deal was the greatest achievement of his father’s career. The first public, guaranteed sale of something that had been to the Moon, done by “this small German company realizing something.” But despite his positive memories of the episode, when he heard about the 2014 sale of a Sieger stamp from RR Auction, it gave him pause. “Fifty thousand dollars, from my point of view, is too much,” he says.

The recent carte blanche on selling space objects, with auction houses and consultants taking percentage cuts, tech entrepreneurs investing in a nascent market, and astronauts who can now contribute from their personal collections and hike up prices with authentication documents may seem to leave the spurned crew of Apollo 15 in the cold. But, according to Gunter, the F.B.I. visit in the early 70s was not the last time that he heard about the Apollo 15 astronauts.

One day, almost a decade after the incident with the covers, Gunter was at his desk in the open-plan, 21,500-square-foot Sieger offices. This was in the pre-Internet days, and visitors—representatives from agencies, buyers from U.S. stamp companies—often came to the floor. But this guest was unusual. Gunter looked up and saw a man making his way down the rows of employees toward Hermann Sieger’s office in the back. “It was surprising. It was something special,” Gunter recalls.

Years earlier, Hermann Sieger had quietly put together three albums of rare stamps from his own store, worth at least $7,000—one for each astronaut. Almost 10 years after he’d walked on the Moon, an Apollo 15 astronaut had arrived in Lorch to pick up his stamps.

Emily Ludolph is a writer based in New York.