Image caption Gagarin's flight lasted 108 minutes

A movie has been made on the space station that tries to show what Yuri Gagarin might have seen on his historic flight around the Earth in 1961.

FirstOrbit will have a YouTube premiere next month to celebrate the Russian cosmonaut's achievement 50 years on.

No film exists showing what Gagarin saw through the viewports of his Vostok capsule; there is only an audio recording of his observations.

This has now been matched to high-definition video shot from the station.

"When you combine these pictures of what he was genuinely able to see with the excitement and tingle in his voice, it's quite amazing," film director and space historian Dr Chris Riley told BBC News.

Yuri Gagarin became the first human to venture above the Earth's atmosphere when he blasted away from the Tyuratam missile range (now the Baikonur Cosmodrome) in Kazakhstan at 0607 GMT on 12 April 1961.

His 108-minute journey around the globe took him across the Soviet republics, across the Pacific Ocean, over the Straits of Magellan in South America, above the Atlantic and Africa before re-entry and a bailout back to the ground near the city of Engels in south-west Russia.

The view down to Earth along this same path has now been filmed from the International Space Station (ISS).

The pictures recorded from the orbiting platform cannot be a perfect match for Gagarin's view.

For one thing, the cosmonaut flew a path that took him closer to the poles than is possible on the ISS. The precise cloud formations 50 years ago also can never be recreated.

But the team behind the movie project hopes the sequence will nevertheless give viewers something of the sensation Gagarin must have experienced.

Image caption Filming on the station was led by Paolo Nespoli

Organising the filming onboard the busy space lab was not straightforward, said Dr Riley.

"My stipulation was that we had to film it at the same time of day that Gagarin had seen it, to get the Sun angles right," he explained. "Those chances only happen every six weeks."

The director of photography on the project was Paolo Nespoli, the European Space Agency astronaut currently living aboard the station.

The Italian is a keen photographer and his still images of the Earth taken from orbit have a big following on Flickr.

Image caption Gagarin went into darkness behind the Earth over the Pacific. He saw the Sun rise as he was moving over the South Atlantic

For FirstOrbit, he set up a camera in the station's Cupola, a kind of turret on the underside of the platform.

The Cupola has seven windows, including one that is 80cm in diameter and faces directly down to Earth.

Nespoli and his astronaut colleagues on the platform ran the camera whenever the station passed over portions of the Earth's surface that Gagarin saw.

This video was then stitched together with Gagarin's capsule recording and a music soundtrack from the composer Philip Sheppard.

Interwoven also are news reports from Radio Moscow, Tass and the BBC.

The movie will be premiered on YouTube on this year's 50th anniversary and then will be available for free download.

"Right from the very beginning, our thought was to make it and then give it away," said Dr Riley.

"Once it became clear we were making this film for all mankind to celebrate the 50th anniversary of Gagarin's flight, everyone just threw their weight behind it without any payment."

Trailers are already available.

Image caption From the Cupola: US astronaut Tracy Caldwell Dyson takes in the spectacular view of Earth from orbit

Jonathan.Amos-INTERNET@bbc.co.uk