NASA space-flown Gemini and Apollo medallions were mission-specific commemorative medallions, often astronaut-designed, which were approved by NASA and carried aboard the mission spacecraft into orbit. Beginning with the first crewed Gemini mission in 1965, commemorative medallions were prepared for the astronauts at their request. These were produced by a company only known as Fliteline and were struck either in a pewter-colored base metal, sometimes painted a gold color, or sterling silver, and were flown on all 10 crewed Gemini missions. A Fliteline medallion was designed and produced for Apollo 1, but was never officially flown after a disastrous cabin fire during a launch rehearsal killed the flight crew.

The Robbins Company of Attleboro, Massachusetts, was contracted in 1968 to produce commemorative medallions beginning with Apollo 7, the first crewed Apollo flight since the Apollo 1 disaster. These were purchased by astronauts and support crew personnel at NASA Astronaut Flight Office, and a total of over 3,000 sterling silver Robbins medallions were flown into space across the 12 crewed flights of the Apollo program. Some of these were later sold in public auction for up to $60,000. The basic elements of the medallion design are consistent throughout the 12 medallions in the series, with the main design element and the mission name on the obverse, mission dates on the reverse, primary flight crew names on either the obverse or reverse, and a serial number either on the lower reverse or on the rim. A very small number of Apollo Robbins medallions were also struck in 14k gold, generally ordered by the mission crew as a personal memento. Sterling silver Robbins medallions have continued to be struck for every crewed NASA spaceflight, including Skylab and Space Shuttle missions.^{[1][nb 1]}

Numismatic souvenirs have accompanied astronauts on nearly every early spaceflight.^[3] Mercury astronauts carried small light-weight mementos on their missions, often in the form of US coins or banknotes. On the first sub-orbital flight (Mercury-Redstone 3), Alan Shepard carried with him four one-dollar silver certificates which were subsequently signed by him, other Mercury astronauts, and support staff becoming short snorters. John Glenn, piloting the first crewed U.S. orbital spaceflight Mercury-Atlas 6 also carried several one-dollar silver certificates.

Space-flown numismatic items are also known for early Gemini missions. On the first crewed Gemini flight (Gemini 3), Grissom and Young brought 50 two-dollar bills.^[4] Young also made history for smuggling "contraband" on board the flight, in the form of a corned-beef sandwich.^[5][6][7]

Beginning with the first crewed Gemini mission in March 1965, commemorative medallions were prepared for the astronauts at their request. It is unclear who prepared these early medallions, only that each individual box containing a medallion bore the word "Fliteline".^[8] It is unknown how many gold and silver colored medallions were prepared for each mission, and how many were space-flown versus unflown. Fliteline medallions were prepared for each of the crewed Gemini flights, as well as the ill-fated Apollo 1 mission.

The Robbins Company was founded in 1892 by jeweler Charles M. Robbins, in Attleboro, Massachusetts.^[20] They began designing and producing commemorative badges for Ohio in 1913,^[21] and South Dakota in 1917.^[22] In 1935, the first 1,000 badges of a new design for the Federal Bureau of Investigation were produced by Robbins.^[23] The Robbins Company also struck the Olympic medals for the 1932 Winter Games in Lake Placid, New York.^[20]

Despite the NASA prohibition on commercializing the medallions, since 1995 there have been over 500 internet or live auction appearances of Apollo mission Robbins medallions.^[63] Two auction companies account for a majority of the sales: Heritage Auctions (over 200 since 2007)^[64] and RR Auction (over 100 since 2011).^[65] Between both auction companies, the top 10 prices realized range from US$30,000 to nearly $62,000, all for sterling silver medallions from either Apollo 11 or Apollo 17.^[66][67] A gold Robbins medallion from the Apollo 11 mission that belonged to astronaut Neil Armstrong sold for over $2 million in July 2019.^[68]