CHICAGO (CBS) — A priceless piece of space history mistakenly sold at a government auction two years ago is on the auction block again, and could net up to $4 million.

The auction comes on the 48th anniversary of the Apollo 11 moon landing.

Astronauts Neil Armstrong and Buzz Aldrin, the first humans to walk on the moon, collected moon rocks to be studied for years to come. Upon touchdown, Armstrong used one little bag to quickly store the samples.

Two years ago, the federal government mistakenly sold the bag of moon rocks at auction. Nancy Lee Carlson, of Inverness, bought the bag for $995, and sent it to NASA to confirm it was real.

After tests verified it was legitimate, NASA refused to send the moon rocks back, claiming it was their property.

Carlson filed a lawsuit, and in February a judge ruled the bag belonged to her.

Now the bag of moon rocks has been put up for auction again. Sotheby’s has estimated it will bring in $2 million to $4 million.

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