Audiences worldwide have grown up with evocative images of astronauts landing on the moon. Who hasn’t seen a triumphant Neil Armstrong make that ‘one giant leap for mankind’?

So it was surprising to view the visually stunning, previously unseen footage that comprises much of David Sington’s feature In the Shadow of the Moon, which opened the 2007 Hot Docs festival. The U.K. doc displays an astonishing range of archival material assembled by Sington’s team, led by producer Duncan Copp, coproducer Christopher Riley and head researcher Sarah Kinsella.

The film, which captured the World Cinema Audience Award at Sundance, is a look back at the Apollo moon missions through the eyes of astronauts including Jim Lovell, Alan Bean and Buzz Aldrin.

After each mission, NASA produced a half-hour doc pieced together from material it shot both on the ground and in space.

‘Those films were made available to the media, and became the source of the stock footage you’ve seen on endless television documentaries,’ explains Sington, on the phone from Seattle, WA, during a U.S. tour.

He and Copp found out that NASA had shot far more footage than what had previously aired. Ten thousand film cans of 16mm film had been stored in liquid nitrogen for decades, and are only being released to the public this year. Due to a cordial relationship that Copp and Sington formed with NASA while making a film about a contemporary space travel mission, they became the first producer-director team to access the complete archives.

A treasure trove of perfectly preserved, unviewed material was made available to them and coproducer Riley, who was thrilled to get his hands ‘dirty with the film cans.’ Although Riley is a prolific director for BBC science shows and has worked on NASA astrobiology missions, his account of his days at the archives reads like a boy’s own adventure.

‘After going through all 10,000 rolls of film on the paper catalogues, I selected the most promising 1,000 rolls, and Duncan and I started viewing them,’ he recalls. ‘From 7:30 in the morning until 4 in the afternoon, we would race around the room pulling film cans and returning them to the shelves – rushing to look at the next roll, wondering what we’d find, noting down the gems and moving on to the next one. The room we were in was so chilled that after the third day of viewing, my back and shoulder seized up. I’d been so engrossed in the film I’d not noticed.’

Sington and Copp worked out an arrangement with NASA to transfer complete rolls of film to HD. All parties agreed that the material was too precious to, as Sington puts it, ‘fiddle around, running it backwards and forwards.’

Like Riley, Sington is an old hand at science docs, but he also speaks with reverence of the NASA footage. He calls a sequence involving a satellite booster leaving its housing and bursting into space ‘the best shot in cinema history, because a) it’s extremely beautiful, b) it’s an enormous achievement to have shot and recovered it from orbit, and c) it represents an extraordinary moment in history, when we finally were able to develop a technology that let us leave the Earth behind.’

Making an archival documentary is costly, so it isn’t surprising that the budget for In the Shadow of the Moon is in the $2-million range. But none of that involved purchasing the NASA material, which is in the public domain. It was transferring the footage to HD that proved expensive – Riley pegs the price tag for the process at $500 per hour.

The film also uses footage from sources other than NASA.

‘We needed shots of X-15 [rocket planes] and test pilots, TV reports of the Apollo mission, ’60s footage and Vietnam,’ Sington recalls. Most of that material, he adds, cost $10,000 a minute, ‘because you have to clear everything. Nobody will buy the film if you haven’t got all the rights.’

He says that, in the end, footage from sources such as CBS cost as much as the NASA material with its hefty transfer fees.

ThinkFilm is opening the film in North American theaters, with a U.S. launch date of Sept. 7 and a Canadian date still to be determined.