11. The shuttle exploded 73 seconds after take-off, killing McNair and 6 other astronauts
The mission marked the darkest day in NASA’s history. At 11:38am EST, Challenger was cleared for launch from Cape Canaveral, Florida. Everything seemed fine initially, and on the video of the launch you can hear crowds cheering. However, after the planned break-up, the shuttle ran into difficulties. After 73 seconds, the Challenger exploded at 46, 000 feet in the air, to the horror of people watching all around the world. NASA employees and spectators alike could only look on in horror. All 7 astronauts on board died, including teacher Christa McAuliffe. Ronald was just 35 years old.