Space Shuttle Challenger exploded 73 seconds after launch in 1986
On January 28, 1986, one of the most tragic moments in spaceflight history unfolded during the launch of mission STS-51-L. The Space Shuttle Challenger broke apart just 1 minute and 13 seconds after liftoff at an altitude of about 29 kilometers, killing all seven astronauts on board.
The disaster occurred shortly after launch from Kennedy Space Center in Florida. The Challenger crew included seven astronauts, among them teacher Christa McAuliffe, who was set to become the first civilian to teach lessons from space.
Investigators later determined that the accident was caused by a failure of an O-ring seal in the right solid rocket booster. Extremely cold temperatures on the morning of the launch prevented the seal from working properly, allowing hot gases to escape and damage the external fuel tank.
The tragedy grounded the Space Shuttle program for nearly three years and led to major safety changes in NASA's future missions.
