Morton Thiokol engineer Roger Boisjoly warned management in a July 1985 memo that the Space Shuttle’s solid rocket-booster O-rings could fail catastrophically. His investigation of a January 1985 flight found that one O-ring had failed and the second had been damaged. He concluded that cold temperatures hardened the rubber, delayed sealing, and allowed hot gases to escape through the booster joint. Further memos and a late-1985 warning that a shuttle mission could end in disaster produced no corrective action.
Before the STS-51-L launch on January 28, 1986, temperatures were forecast to fall to approximately −1 °C (30 °F), and Morton Thiokol engineers recommended postponement during a NASA go/no-go conference. NASA officials questioned the recommendation; managers then privately reconvened without Boisjoly and other engineers and reversed the company’s position, telling NASA that the data was inconclusive. At 58 seconds after launch, the compromised seal failed in high-altitude winds; at approximately 73 seconds, Challenger disintegrated, killing all seven crew members. A presidential commission established by President Ronald Reagan heard Boisjoly’s testimony, and the disaster became a lasting case study in engineering ethics, contractor pressure, and organizational failure. Boisjoly later received the American Association for the Advancement of Science’s 1988 Award for Scientific Freedom and Responsibility.
