Interesting article.
https://www.houstonpublicmedia.org/npr/2026/01/25/g-s1-106940/40-years-after-challenger-lingering-guilt-and-lessons-learned/
Bob Ebeling and other company engineers were watching at the Morton Thiokol booster rocket complex in Utah. They crowded into a conference room with Thiokol managers and executives; all focused on a large projection TV screen.
The night before, in the same conference room, Ebeling and his colleagues had tried to convince NASA booster rocket program managers phoning in from the Marshall Space Flight Center in Alabama that the cold weather made launching risky. The synthetic rubber O-rings lining the booster rocket joints stiffened in cold temperatures, and this would be the coldest launch ever by far. The Thiokol engineers feared blow-by would burn through both sets of O-rings, triggering an explosion at liftoff.
At first, Thiokol's engineers and executives officially recommended a launch delay. But the NASA officials on the line pushed back hard. The launch had already been delayed five times. The NASA officials said the engineers couldn't prove the O-rings would fail. One of those engineers, looking back on it now, 40 years later, says it was an unachievable burden of proof.
"It's impossible to prove that it's unsafe. Essentially, you have to show that it's going to fail," explains Brian Russell, who was a program manager at Morton Thiokol in 1986 and who was focused on the O-rings and booster rocket joints.
