'Gravity': How The Script Changed And Launched Sandra Bullock Into Space

Jonás Cuarón tells MTV News how the Earth-based original script became what it is now.

As we heard yesterday, Alfonso Cuarón's "Gravity" is shaping up to be one of the best movies of the year. Based on a smattering of early reviews from Venice, the tale of two astronauts stranded in space has already captured the imaginations of film fans eager for the weightier fare of the fall movie season.

In anticipation of the upcoming season, MTV News spoke with Jonás Cuarón, who wrote "Gravity" with his dad, for our Fall Movie Preview, and we learned that the space movie had origins set in a very different place.

The story of "Gravity" started four years ago, when the younger Cuarón gave his dad a script to get his feedback, as he has always done, but Alfonso came back with another idea. "When he read it, he really didn't have that much feedback at the time," Jonás told us, "but he wanted to do something in a similar spirit."

Jonás' original idea was based on the premise of delivering 90 straight minutes of nonstop suspense, while still delivering characters and human emotions that the audience could connect with. "The idea was to do basically a roller coaster ride, but not only a roller coaster of adrenaline but also of emotions. We started talking about the best place to set the roller coaster," he said. "For several reasons, we both really like space exploration. In a way, if you're going to set up a story where a character is struggling and having to overcome several obstacles, there is no more terrifying place than space."

So Alfonso and Jonás had their concept and their setting. Now they needed a reason to put their astronauts in peril. Since the father-son duo wanted to keep "Gravity" as scientifically realistic as possible, they researched space exploration looking for something to spur the action. "Doing a little research, we came to this thing called the Kessler syndrome, which is a scenario posed by a NASA scientist that basically says that the density of space junk from satellites, pieces of old space probes, all of this space junk, if it ever collided, it would create a chain reaction that would create cloud of debris. That became our main obstacle for the narrative," Cuarón explained.

Then, all there was left to do was write the thing. "Gravity" started simply enough as a fish-way-out-of-water story, following a novice astronaut (Sandra Bullock) and her more experienced crew mate (George Clooney), but not long after the words began to flow, the Cuaróns ran into another problem.

"Once we started writing 'Gravity,' it started with two characters. The problem was that really soon into it, we were writing the descriptions of the zero-G, and my dad said 'Oh f--k. How are we going to get this done?' " Cuarón said. "It was really interesting to be writing while he was starting to figure that out, but the more challenges I gave him as a writer, the happier he seemed."

"Gravity" opens in theaters on October 4.