Sometimes a coin is more valuable because of where it’s been than what’s in it or how old it is. A small niche area of coin collecting is dedicated to space-flown coins and medals, and there’s more of them than you might think.
NASA has very careful regulations about what can be flown into space, both due to weight and mass restrictions and possible health issues (for instance, legendary astronaut John Young once got in a great deal of trouble for smuggling a corned beef sandwich onto a Gemini flight: the crumbs from the bread could have clogged the air filters.)
The first official mission medallions created for the Gemini and Apollo missions were known as Flitelines, due to the name stamped on each individual box. These were struck in base metal, sometimes painted gold or silver; it is not known how many extant medallions were flown or unflown. All missions had a medallion designed, but the medallions for Apollo 1 were never flown, after the crew died in a training exercise at what is now Kennedy Space Center.
The next crewed Apollo mission was Apollo 7, which renewed the tradition of the medallions, now made by the Robbins Company of Attleboro, Massachusetts. NASA astronauts and personnel purchased the medallions (the only people allowed to do so); over 3000 of the medallions were flown during the Apollo missions. A few were struck in gold, and usually went to mission crew. Medallions in sterling silver have been struck for all crewed NASA missions, including those for Skylab and the space shuttle. (NASA has strict prohibitions against profiting off these medallions, but some do occasionally come up for sale, primarily through Heritage Auctions and RR Auctions. One such medallion sold for nearly $62,000.) Apollo medallions were kept in the Command Service Module, though a small few were actually taken down to the lunar surface.
But official medallions aren’t the only numismatic items to break the surly bonds of earth. Astronauts often carried coins or bills with them on missions as personal mementos. On the first flight of an American into space, Alan Shephard carried several silver certificates, which were later signed by the other astronauts; when John Glenn orbited the earth, he did the same. When Gus Grissom and John Young boarded Gemini 3, in addition to the infamous sandwich, they also carried 50 two-dollar bills.
And the tradition continued even into modern spaceflight. In 2009, NASA presented space-flown Louis Braille Bicentennial silver dollars to the National Federation of the Blind. The coins were flown aboard the shuttle Atlantis’ Hubble servicing mission in May of 2009, and were the first coins to feature tactile Braille.