It looks like director Alfonso Cuaron's new film Gravity may have hit another pretty big snag. According to Deadline Robert Downey Jr. may not be able to co-star in the film anymore due to scheduling conflicts. With the amount of projects the actor is taking on, it's no surprise that he's having scheduling problems with the films he wants to make.
As you know Warner Bros. has seen some casting problems with this film, until they were able to bring on Sandra Bullock, who will play the lead role. "The majority of the 3D film scripted by Cuaron and his son Jonas is definitely carried by the actress in a manner comparable to Tom Hanks's solo performance in Cast Away. The film's heroine is a space station team member hellbent on finding her way back to earth and her daughter, after the station is destroyed by a debris field from an exploded asteroid."
Downey Jr. signed onto the project very early on as the co-pilot and the only other survivor of the asteroid mishap. Both happened to be away in a space ship when the blast hit. The studio is saying that Downey Jr. will not be leaving the project, and they expect to work out these scheduling problems. So he's not officially out of the project yet, but if they can work things out he will. If he does end up leaving it will be yet another huge blow to the project.
Downey Jr. is currently shooting Sherlock Holmes 2, and will soon need to pull all his attention on The Avengers and Iron Man 3. He's also loosely attached to Sam Raimi's Oz, The Great and Powerful.