(via Sotheby's)

In 1969, Neil Armstrong collected some rocks and dust from the surface of the moon during his historic journey to space, later describing the surface as "fine and powdery. I can kick it up loosely with my toe." But what happened to his souvenir next is unclear. What we do know is that when he reached Earth, "the U.S. government emptied it of its contents and dubbed it a national treasure," according to the Washington Post. But then they, uh, sort of lost it.

The bag was lost for decades, but in 2003 it was discovered in the garage of Max Ary, who ran the Cosmosphere in Kansas. Ary was charged for stealing space artifacts and sentenced to 36 months in federal prison, at which time the bag was once again in the hands of the government. And the government dropped the ball once again, this time mislabeling the contents of the bag; according to WaPo:

Federal agents confiscated the bag. But because of a clerical error, it was mislabeled as an item from the 1972 Apollo 17 mission, as Ben Guarino has reported. The sample sacks from that mission weren’t used to gather moon rock, so its apparent value dropped significantly.

According to Sotheby's, "The true history of the bag went unknown for decades until just a year ago." The mislabeled bag "was offered three separate times in 2014 by a small auction house on behalf of the US Marshall’s service, garnering not a single bid. It was relisted again in 2015," and this is when Nancy Carlson, the current owner, purchased the bag at auction for $995.

Carlson took her goods to the Johnson Space Center in Houston, where its contents were confirmed to be a part of the Apollo 11 mission. NASA held on to the bag, Carlson sued to get it back, and the court sided with her—in February, they ordered its return. But NASA (which would like the bag to be in a museum) may have a chance to get it back: Sotheby's New York has announced it will be a part of their Space Exploration auction on July 20th, and they expect it will go for up to $4 million. Carlson plans to donate some of the money to charity.

Sotheby's says this item is "the star lot... the only such relic available for private ownership, it is exceptionally rare."