The Space Shuttle Challenger disaster occurred on January 28, 1986, when the shuttle broke apart 73 seconds after liftoff from Kennedy Space Center in Florida. All seven crew members on board, including teacher Christa McAuliffe, were killed. The disaster was caused by the failure of an O-ring seal in one of the solid rocket boosters, which allowed hot gases to escape and destroy the external fuel tank. The tragedy led to a 32-month suspension of the Space Shuttle program and major changes in NASA's safety procedures.