NPR - Space

40 Years After Challenger: Lingering Guilt and Lessons Learned

Forty years after the Challenger explosion, former Morton Thiokol engineers recount how cold‑temperature O‑ring concerns were dismissed, leading to the shuttle’s catastrophic failure. Engineers Roger Boisjoly, Bob Ebeling and others warned NASA that the stiffened O‑rings could cause blow‑by, but Thiokol executives reversed their recommendation under launch pressure and contractual penalties. The disaster exposed a culture of normalized deviance and suppressed dissent, prompting NASA to overhaul launch‑decision protocols—yet similar communication failures resurfaced in the Columbia tragedy. Today, the lingering guilt of the engineers drives a renewed emphasis on safety culture and listening to dissenting voices.