Rocket science is inherently dangerous. With significant quantities of fuel and oxidizer under pressure in the presence of fire, testing a rocket engine is basically containing and measuring an explosion. Modern tests are done with safety in mind, but this wasn’t the case 80 years ago. In the 1930s, when rocket engines were still an unproven technology, engineers routinely ran tests in frighteningly unsafe conditions, surviving mainly on luck. But on May 17, 1930, Max Valier’s luck ran out.