Alfonso Cuarón's Film "Gravity"
Credit: Warner Bros

Alfonso Cuarón is one of the most ambitious directors in Hollywood – so ambitious that even James Cameron, legendarily exacting director of 'Titanic' and 'Avatar,' told Cuarón that his latest film, set entirely in space, might be impossible to make.

"Alfonso is always exploring," says cinematographer Emmanuel Lubezki, a longtime collaborator who's been nominated for five Academy Awards. "He looks to use the tools of cinema in an interesting way."

For 'Gravity,' however – the story of an astronaut (Sandra Bullock) stranded 372 miles above Earth – Cuarón and his team had to invent a whole new toolbox. The technology needed to create a convincing portrayal of zero gravity that, as Cameron suspected, simply didn't exist.

"Ninety-nine percent of the equipment we used was custom-made," says Lubezki. "This movie could not have existed even a year ago."

Over nearly five years, Cuarón, Lubezki, and visual effects supervisor Tim Webber (an Oscar nominee for 'The Dark Knight'), pushed film tech and CGI to new heights to bring a stunning level of realism to the film. They commissioned an automotive robot manufacturer to make a super-nimble bot with a specialized camera head so Cuarón could pull off dramatic, fluid long shots (a signature of his style) that mimic the sensation of being in unmoored space.

Webber designed an improved "puppeteering" rig – a system of 12 wires that suspended and manipulated Bullock so she could "float" through a space station. (The process wasn't foolproof: With Bullock's computer-generated suit off, her arms and legs exposed, "you could see the strain in her muscles caused by holding a leg up in gravity," Webber says. "Little things like the angle of her foot would give something away, and we'd have to cut it and rotate it slightly in postproduction.")

To keep the unchanging background – black sky, a crescent of Earth or sun – interesting, and to accurately light Bullock and co-star George Clooney as their characters hurtle through space, Lubezki invented a 12-foot-x-12-foot cube made of more than a million LEDs. With the actors inside, the filmmakers could rapidly project any kind of lighting onto their faces.

"Right now it sounds cool," Lubezki says, "but in reality it was frightening. Alfonso's script was brilliant, but we didn't have any idea of the monstrosity he was creating."