Sandra Bullock lost in space in harrowing "Gravity" trailer [VIDEO]

Dr. Ryan Stone and Matt Kowalsky, played by Sandra Bullock and George Clooney, go on a spacewalk in this single-shot trailer for "Gravity," set to premiere at the Venice Film Festival next month.

Space debris strikes the spacecraft astronauts are working on, and in the ensuing panic, the crew loses contact with Earth. The harrowing minutes that follow end with Dr. Stone being flung far out into space, alone.

Clooney, as Kowalsky, makes a last attempt to contact Earth, saying, "Houston, I've lost visuals on Dr. Stone."

The sci-fi thriller, directed and co-written by Alfonso Cuarón, was much anticipated at Comic-Con, which he attended with Bullock. The actress said her fear of heights made filming a challenge, but added that her dance training helped her work in the spacesuit.