Comic-Con: The bizarre story of how Sandra Bullock spent ‘Gravity’ shoot locked away in an isolated cube

When director Alfonso Cuarón set out to make his next film, “Gravity,” he knew capturing the scenes of astronauts floating through space would require the use of innovative, new technology.

And for unlucky star Sandra Bullock, that meant spending 10 hours a day locked in a 9-by-9-foot cube that kept her isolated from her fellow cast members, and the world. Furthermore, inside the cube, she was strapped in a harness that kept her largely immobile. For comparison, the average prison cell measures 8 feet by 6 feet.

“There was no improvising. The physical part was so scary,” Bullock said of her experience during an appearance in support of the upcoming film at Comic-Con on Saturday.

Not only was Bullock locked inside the cube during filming, but Cuarón used a special camera that would rush toward Bullock’s face at 25 mph, stopping only about an inch from her face, according to producer David Heyman. And because she was strapped in place inside the cube, there was no way for her to move out of the camera’s way should something go wrong.

“What was even scarier than that was the technology was being created on the spot,” Bullock said. Cuarón "was like the evil puppeteer. If that robot did decide to continue through my face, I couldn't have gotten out of the way.”

The film crew created the cube to capture footage that would accurately simulate the look of an astronaut floating through the darkness of space. "The cube was designed to continually capture her point of view while floating alone in space," Cuarón said.

Bullock spent so much time hidden away inside the cube that she and the crew had to come up with creative ways to help keep her from going stir-crazy.

“They had me strung up for 8-10 hours day,” she said. “I learned to meditate up there. Alfonso gave me boxes of CDs with sounds that would set the tone for a scene and help me stay in the right head space.”

Still, Bullock said the isolation and cramped space were preferable to the original plan: Sending her and co-star George Clooney into a “vomit comet,” a reduced-gravity airplane that flies up into the Earth’s stratosphere and then enters periods of free fall, dropping several thousand feet per second, briefly creating a zero-gravity environment.

“It was a very intense experience for Sandra,” Cuarón said. “Sandra was completely insulated inside that cube. In between takes, she would stay inside there, with her music, inside her zone.”