Sandra Bullock’s new movie trailer for `Gravity’ finds her stranded in space with George Clooney. Not a bad thought until you realize that they had to shoot ten hours a day in a 9’x9’ cube that wasn’t much bigger than a prison cell. Shooting “Gravity” It was like solitary confinement in space.

“There was no improvising. The physical part was so scary,” Sandra Bullock said. Still, it was better than the original “Gravity” plan, which was to shoot in a “vomit comet,” a reduced-gravity plane that flies into the Earth’s stratosphere and then goes into free fall, dropping thousands of feet in a second to create a a zero-gravity environment.

Sandra Bullock told a Comic-Con audience that she filmed “Gravity” isolated from her co-stars and strapped in a harness where she could barely move while wearing her spacesuit. Director Alfonso Cuarón also used a special camera that would rush 25 mph and stop about an inch from her face, which she was barely able to move if anything went wrong.

Cuaron used innovative, new film technology wanted to create the effects of astronauts floating through space. Bullock says “What was even scarier than that was the technology was being created on the spot. (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 cube was essential to accurately capture footage that would look like an an astronaut floating through space. Cuarón said "The cube was designed to continually capture her point of view while floating alone in space."

To stay in character, Bullock chose to stay in the cube between takes and had to talk to the director Cuarón by radio. Sandra Bullock spent so much time in the solitary confinement of the set that had to fight going stir-crazy. She said, “They had me strung up for 8-10 hours day. 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.”

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

Cuarón told the audience at Comic-Con that Bullock and Clooney are the only two actors in the entire film.

“Gravity” premieres on October 4.