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1986: Challenger On January 28, the space shuttle Challenger took off safely with six astronauts and a high school teacher, Christa McAuliffe, aboard. But tragedy soon struck. O-rings that sealed gaps between segments of the solid-rocket boosters were designed to flex, compensating for the sudden increase of pressure created by the boosters' ignition. But due to the unusual cold that day, the O-rings momentarily failed, allowing hot gases to leak. Fifty-nine seconds into the flight, a small flame emerged on the side of the rocket and quickly spread to the propellant tank and the strut that secured the booster. The liquid hydrogen ignited, and the propellant tank ruptured. The solid booster then broke free of the strut and crashed into the booster, causing the unit to explode and killing all seven astronauts. It was the worst space disaster in history. Continue: 1990 Photo: NASA. Q&A | Tour of Mir | Day in the Life Next Space Station | Mishaps | Resources Teacher's Guide | Transcript | Site Map | Terror Home Editor's Picks | Previous Sites | Join Us/E-mail | TV/Web Schedule About NOVA | Teachers | Site Map | Shop | Jobs | Search | To print PBS Online | NOVA Online | WGBH © | Updated November 2000 |
Challenger explosion.