50 years ago today Yuri Gagarin became the first man in space.

The Russian's orbit of the Earth lasted just 108 minutes but paved the way for more than 500 astronauts to follow and a raft of space related memorabilia that has been enthralling investors for decades.

The 27-year-old had no control over his tiny spacecraft once in orbit, which was operated by radio signals from Earth. Upon re-entry, Gagarin ejected from his capsule and landed safely in the Saratov region of the Soviet Union, near the city of Engels.

The capsule is now on display at the museum of rocket engineer RKK Energiya and while it is unlikely to head to auction anytime soon, its companion test capsule comes to auction today at Sotheby's in New York.

Estimates for the test capsule range from $2m to $10m

The test capsule, sent up just three weeks before Gagarin's historic orbit, has a wide pre-sale estimate, ranging from $2m to $10m.

David Redden, the head of Sotheby's special projects department, comments: "It's an extraordinary object that makes [the history of the flight] real and also totally terrifying."