As Apollo 13 astronaut Fred Haise floated in the tunnel snaking between the Lunar Module and Command Module, he heard—and felt—a loud bang. Around him, the two vehicles began to contort. Then, the metal walls of the tunnel crinkled as the spacecraft shuddered.
Wide-eyed, Haise scrambled from the tunnel into the Command Module alongside Jack Swigert and their commander, Jim Lovell. From his customary position at Lovell’s right, Haise quickly assessed something was drastically wrong with the spacecraft’s cryogenic tanks—the oxygen was just gone. Fortunately, there didn’t seem to have been a chemical explosion, because only a thin wall separated the oxygen tank from the propellant tanks used to power the spacecraft’s main engine.
“It really didn’t explode like something you think of with shrapnel,” Haise told Ars, in an interview. “It just over-pressurized, and then it let go some steam. If it had been a shrapnel-type explosion, I wouldn’t be here today.”