Challenger explodes

January 28, 1986

Seventy-three seconds after lifting off from Cape Canaveral on a cold January morning, the space shuttle Challenger disintegrated in a clear Florida sky. Seven astronauts died, including a New Hampshire schoolteacher named Christa McAuliffe. Millions of American schoolchildren had been watching live in their classrooms. An O-ring had failed in the cold. NASA lost its innocence.