Whether there would be time for forensic work before the spacecraft died was unclear—something Liebergot understood better than anyone else. It was time, he knew, to ask the question that had been playing around the edge of his mind for the past ten minutes—and, he suspected, was on a lot of...

TIME’s Jeffrey Kluger takes you through the Soyuz 11 mission and the events that make it one of the most harrowing space missions of all time.