This Day in History:, Challenger Disaster. January 28, 1986. 73 seconds after its 11:38 a.m. launch, NASA's space shuttle exploded, killing all seven crew members. Among the crew was Christa McAuliffe, a 37-year-old high school social studies teacher from New Hampshire. McAuliffe had won a competition that earned her a place on the Challenger. Millions witnessed the tragedy on live television. In the aftermath, President Ronald Reagan appointed a special commission to determine what went wrong with Challenger. The investigation determined the disaster was caused by the failure of an “O-ring” seal due to cold weather. It would be two years before NASA sent astronauts into space again
