It was late on the night of January 27, 1986, when Roger Boisjoly realized that something terrible was about to happen. A 47-year-old senior scientist at Morton Thiokol’s Wasatch Division, a NASA contractor based in northern Utah, Boisjoly had spent months battling his superiors, trying—with increasing desperation—to draw attention to what he had come to believe was a potentially catastrophic fault with the Challenger Space Shuttle. In the middle of a last-minute teleconference in which he had recommended that the upcoming launch, the shuttle’s 25th mission, be stopped on account of low temperatures on the pad, Boisjoly feared the worst. His managers had listened to his argument and considered his data but seemed poised to ignore him yet again.
Almost exactly a year before, during one of his regular post-flight inspections at Cape Canaveral, Boisjoly had discovered unusual charring in one of the synthetic-rubber O-rings, which sealed the joints of the massive booster rockets that helped propel the shuttle into orbit. Hot gas burning at more than 5,000 degrees Fahrenheit had apparently escaped from inside the rocket in the milliseconds after it ignited, blowing right past the seal and leaving a trail of coal-black soot in its path.
