In another hit to Alfonso Cuaron space thriller GRAVITY, Robert Downey Jr. has left the project, according to The Hollywood Reporter. Downey Jr. had been cast in a small role that only lasts the first act. Sandra Bullock is still in talks to take the lead after Angelina Jolie dropped out and Natalie Portman passed. The story follows a female astronaut trapped in space after satellite debris destroys her space station.