ChronoFive
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Setting the scene
By 1986, NASA's Space Shuttle program was operational, with 24 successful missions since 1981. The shuttle was portrayed as routine and safe, and NASA faced pressure to increase flight frequency. The Challenger mission STS-51-L was to deploy a satellite and carry Christa McAuliffe, a New Hampshire teacher selected for the Teacher in Space program, which would broadcast lessons from orbit. The launch had been delayed multiple times due to weather. On January 28, 1986, temperatures at Cape Canaveral dropped to 18°F (-8°C) overnight, far below the shuttle's design specifications.
What happened
At 11:38 a.m., Challenger lifted off. At 73 seconds into flight, at 46,000 feet, a booster rocket seal failed due to the cold, allowing hot gas to escape and ignite the external fuel tank. The shuttle broke apart in a fireball. All seven crew members—Francis Scobee, Michael Smith, Judith Resnik, Ellison Onizuka, Ronald McNair, Gregory Jarvis, and Christa McAuliffe—were killed. The disaster was broadcast live on television, watched by millions of schoolchildren. The crew cabin remained intact after breakup and fell into the Atlantic; the astronauts likely survived the initial explosion but died on impact with the ocean.
Why it still matters
The Challenger disaster was caused by NASA's organizational failures—engineers at Morton Thiokol had warned about O-ring failures in cold weather, but managers overruled them under schedule pressure. The Rogers Commission, led by physicist Richard Feynman, famously demonstrated the O-ring failure with a glass of ice water on television. The disaster grounded the shuttle fleet for 32 months and led to major NASA reforms. It shattered the illusion of routine spaceflight and demonstrated that space travel remained inherently dangerous. The disaster also highlighted the risks of political pressure on technical decisions. The crew is memorialized at Arlington National Cemetery and in schools named for McAuliffe and the others.
Background
The Rogers Commission investigated the O-ring failure.