Acclaimed Mexican director Alfonso Cuaron has tapped Oscar-winning actress Sandra Bullock to headline his upcoming sci-fi thriller Gravity. Written by Cuaron and his son Jonas, the film follows the sole survivor of a space expedition gone wrong as she attempts to find a way back home.

Bullock will play the story’s sole survivor and be alone onscreen for most of the film’s duration. The role was originally offered to Angelina Jollie and Natalie Portman.

Robert Downey Jr. is also attached to star, but scheduling conflicts may keep that from happening.

Gravity marks Bullock’s return to sci-fi since the 1993 Sylvester Stallone vehicle Demolition Man. Cuaron’s creds include Children of Men, Harry Potter and the Prisoner of Azkaban, and Y Tu Mama Tambien.