Challenger Disaster
Space Shuttle Challenger broke apart 73 seconds after launch, killing all seven crew
January 28, 1986
73 Seconds
On January 28, 1986, the Space Shuttle Challenger lifted off from Kennedy Space Center in unusually cold weather. Seventy-three seconds later, it broke apart over the Atlantic Ocean, killing all seven crew members. Among them was Christa McAuliffe, a high school teacher from New Hampshire who had been selected from 11,000 applicants to be the first teacher in space. Millions of schoolchildren were watching live.
What Went Wrong
The cause was an O-ring — a rubber seal — in one of the solid rocket boosters that became brittle in the overnight temperatures of 28°F (-2°C). Engineers at the contractor Morton Thiokol had warned NASA the night before the launch that the O-rings had never been tested at such low temperatures. NASA managers overruled their concerns. Hot gas leaked through the failed seal and ignited the external fuel tank, tearing the spacecraft apart.
The Fallout
President Reagan appointed the Rogers Commission to investigate. Physicist Richard Feynman famously demonstrated the O-ring failure live on television by dropping a piece of the material into a glass of ice water. NASA grounded the shuttle program for nearly three years. The disaster reshaped how NASA communicated risk and made engineering objections much harder for managers to ignore. The Columbia disaster in 2003 showed those lessons hadn't fully stuck.