The Challenger Disaster

It was a cold January morning on January 28, 1986. They delayed the launch of the Challenger 2 times because of the cold weather. The third time, they let it take off. The Challenger took off. Everything looked good. Then 73 seconds into launch, Commander Scobee said "Go with throttle up!" The Challenger then exploded. All seven astronauts including the first teacher in space, Christa McAuliffe, were killed. It was later determined that the Challenger disaster was because of a defective O-ring.