STS-51L: the Challenger disaster
73 seconds after liftoff, Space Shuttle Challenger explodes when a rubber O-ring designed to be a tight seal between solid rocket booster segments allows flames from the booster to breach the shuttle’s external fuel tank, causing the tank’s highly flammable contents to ignite. The shuttle is destroyed with all hands aboard. Later analysis reveals that frigid cold temperatures in the nights leading up to the launch allowed the booster’s O-rings to become brittle enough to break – a possibility that NASA had been warned of by engineers at Morton-Thiokol, the contractor responsible for the solid rocket boosters.
Lost in the explosion are Commander Francis R. Scobee, Pilot Michael Smith, mission specialists Judy Resnik, Ellison Onizuka and Ronald McNair, and payload specialists Gregory Jarvis and Christa McAuliffe, the highly-publicized first “teacher in space.”
The Space Shuttle program is grounded for over two years during an investigation and an extensive review of safety and launch procedures.