Space Shuttle Challenger breaks apart after launch
A frozen O-ring fails 73 seconds into flight, killing all seven aboard including a schoolteacher
Quick facts
- Agency
- NASA
- Mission
- STS-51L
- Cause
- O-ring failure in cold weather
- Crew lost
- 7 (incl. Christa McAuliffe)
What happened
On 28 January 1986, Space Shuttle Challenger broke apart 73 seconds into the flight of mission STS-51L, killing all seven crew members: Dick Scobee, Michael Smith, Ellison Onizuka, Judith Resnik, Ronald McNair, Gregory Jarvis, and Christa McAuliffe, a New Hampshire schoolteacher who would have been the first private citizen in space. The Rogers Commission, which investigated the disaster, found that a rubber O-ring seal in the right solid rocket booster had failed after becoming brittle in unusually cold weather at the launch pad. Engineers at Morton Thiokol, the booster's manufacturer, had explicitly warned the night before that O-rings should not be flown below 53 degrees Fahrenheit; the temperature at launch was 36 degrees. The Commission's report concluded plainly that had decisionmakers known all the facts, 'it is highly unlikely that they would have decided to launch.'
Why it matters
The disaster grounded the shuttle fleet for nearly three years while NASA redesigned the solid rocket booster joints and overhauled its launch decision process, and it became a defining case study, still taught in engineering ethics courses, of how organizational pressure can override known technical warnings.
How we know
The Rogers Commission's official report, preserved on NASA's own site, documents the O-ring temperature threshold, the overnight engineering warnings, and the Commission's finding that the launch decision was flawed; NASA's own accident page separately confirms the timing and crew.
Sources
- NASA. Challenger STS-51L Accident · Primary source (author-declared)nasa.gov · Cited as a "primary" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)
- Rogers Commission (hosted by NASA). Report of the Presidential Commission on the Space Shuttle Challenger Accident, Vol. 1, Ch. 5 · Primary source (author-declared)nasa.gov · Cited as a "primary" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)
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