On February 15, 2015, an Illinois woman named Nancy Carlson scored the deal of a lifetime: the bag that once contained the first-ever sample collected from the Moon was sold to her for the bargain price of $995. Now NASA is saying the transaction was a mistake, and the two parties are caught up in a legal battle surrounding the precious artifact, AP reports.

The bag’s story begins with the Apollo 11 lunar mission of 1969. Astronauts used the white bag—labeled with the words “Lunar Sample Return”—to transport Moon rocks back to Earth. The bag’s connection to the Apollo spaceflight and the traces of Moon dust still present in the fabric make it, in the government’s words: “a rare artifact, if not a national treasure.”

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In 2003, the bag was found in the possession of Max Ary, the founder and former director of the Cosmosphere in Kansas. Ary was convicted in 2005 of stealing hundreds of space treasures, including some on loan from NASA. After the bag was returned to NASA, a computer error resulted in the confusion of the item for another sample bag used in a later mission. Due to the case of mistaken identity, the Apollo 11 bag ended up on the auction block, where it was sold to Carlson for a fraction of its true value.

NASA was made aware of the misunderstanding when Carlson sent the bag to the Johnson Space Center for authentication. Once they identified it, they refused to hand it back to her, and the successful bidder smacked the agency with a lawsuit for “unwarranted seizure of my personal property,” ignoring NASA’s offer of a full reimbursement plus $1000 “to offset any inconvenience.”

Artifacts from Apollo missions tend to perform impressively well at auction. In 2014, the glove liner worn by Buzz Aldrin during his Apollo 11 mission sold for $61,212 and a hand controller from the Apollo 15 module sold for $610,063. It makes sense, then, that a bag embedded with 50-year-old Moon dirt would be worth fighting for.