It is one of 14 Hasselblad cameras used by NASA astronauts during the moon landings and is the only one known to have been returned to earth. The rest were left on the surface of the moon to free up weight to bring back rock samples and only the exposed film magazines made the journey back. Apparently the astronaut who used it, Jim Irwin, was having difficulty with the wind on and he was instructed to bring it back for inspection. All in all he made 299 exposures both on the moon and during the journeys there and back, so low usage is another plus point.
Quite how it has ended up at the Westlicht auction house is a mystery as I would have expected something like this to have been put on display at the Smithsonian. I doubt that even cash strapped NASA needed the money that badly. Westlicht's website is not exactly forthcoming on the provenance and relies on markings on the camera and serial numbers to verify authenticity.
Estimated price is €200,000 and you have until 22 March to save up your pennies. Otherwise there are 13 others scattered at various points across the the moon and are yours for the taking.
http://www.westlicht-auction.com/index.php?id=4&L=1