Only 3 Astronauts Have Actually Died In Space

For many wannabe astronauts, the idea of venturing into the great unknown would be a dream come true, but over the past 50 years there have been a slew of spaceflight-related tragedies that are more like an astronaut's worst nightmare. In the last half-century, about 30 astronauts and cosmonauts have died while training for or attempting dangerous space missions. However, the vast majority of these deaths occurred either on the ground or in Earth's atmosphere — below the accepted boundary of space called the Kármán line, which begins at an altitude of about 62 miles. Of the roughly 550 people who have so far ventured into space, only three have actually died there, and those were the astronauts of Apollo 1. In January 1967, a fire on Apollo 1 killed astronauts Gus Grissom, Ed White, and Roger Chaffee. During a launch simulation, a stray spark ignited within the cabin of the grounded spacecraft, which was filled with pure oxygen. This led to an uncontrollable fire that quickly overwhelmed the doomed crew, leading to their tragic deaths as they struggled in vain to open the pressurized hatch door. The autopsy report determined that the primary cause of death for all three astronauts was cardiac arrest caused by high concentrations of carbon monoxide.