"It is the worst disaster in the history of the American space program." Forty years ago on January 28, 1986, the space shuttle Challenger exploded 73 seconds after liftoff from Cape Canaveral, killing all seven crew members, including school teacher Christa McAuliffe from New Hampshire, who had won a national competition to become the first teacher in space. Peter Jennings anchored ABC's World News Tonight from Washington, with John Quiñones leading off the broadcast's coverage. | ABC World New

On January 28, 1986, the Space Shuttle Challenger disintegrated over the Atlantic Ocean just 73 seconds after launching from Kennedy Space Center in Florida. The disaster was caused by the failure of two O-ring seals in the right solid rocket booster. Record-breaking cold temperatures on the launch pad had caused the rubber rings to become brittle and lose their elasticity. This allowed superheated gas to burn through the joint like a blowtorch, eventually causing the external fuel tank to colla