Twenty-four-year-old Ukrainian Valentin Bondarenko, the youngest Soviet cosmonaut, trains in a pressurized cabin with 100% oxygen. He wipes his skin with a cotton ball moistened with alcohol and throws it to the floor. The cotton swabs onto a hot metal plate and catches fire, quickly spreading to Valentin’s spacesuit. It takes them a few minutes to open the hatch and pull him out, but he’s almost completely covered in third-degree burns. Eight hours later, he’s dead. A similar accident will also befall the three Americans on Apollo 1, unaware of the same problem that befell the Soviet.
