Morton Thiokol, Inc.

The loss of Challenger is often remembered as a cold-weather O-ring failure and a single launch-eve reversal. The official record is more demanding. A field joint whose sealing behavior was not fully understood accumulated anomalies across years of tests and flights; contractor engineers made a temperature-based no-launch recommendation; contractor management reversed it after a contested conference; critical information did not reach the senior officials who certified the mission; and a safety organization with no effective voice failed to stop the chain. Accountability therefore rests not only on the last approval, but on who controlled design, anomaly interpretation, launch constraints, dissent, schedule, certification, redesign and proof that the repaired system could withstand its real operating envelope.