Space Shuttle O-ring failure

Previous O-ring damage on cold-weather launches (40°F) was the precedent; the Challenger launch at 28°F was unprecedented.

If she wasn't up in space, it was "here I am from the Holiday Inn in Cape Kennedy," rather than "here I am from 120 miles above." So there was a political reality there. The engineer says, it's too cold, the O-rings are too stiff because they're so cold, it's not going to work. They had previous history of O-ring damage — they had double O-rings for redundancy, and they had almost blown one of these things before when the outside temperature was like 40 degrees, and now it was 28 degrees. They said, oh well, we've flown cold missions before — yeah, but never this cold. That's just someone trying to gloss it over.

Feynman on the Rogers Commission. NASA's pre-flight probabilistic analysis claimed one-in-10,000 failure rate; Feynman pointed out four percent of missiles since 1947 had failed, and this was the 25th shuttle flight. Used to make a teaching point about how engineers should be skeptical of probabilistic risk analyses produced by experts paid to produce them.

Have you ever heard the story of how Feynman analyzed the space shuttle? NASA had done this big safety analysis, and they proved by all this probabilistic — probably paid some professor at some well-known Eastern University to help them with this — there was one chance in 10,000 of the space shuttle failing on launch. And then when it failed on launch, Feynman was part of the blue-ribbon panel that was supposed to figure out what was going on, and they learned it was the O-rings, in the cold weather — there's a whole book written on this stuff. But Feynman basically pointed out that, since Wernher von Braun — we stole him from Germany — we took all the great scientists out of Germany before World War Two. The center of science in the world was Germany, not the United States. In 1900 you were required at MIT to take several semesters of German so you could read the scientific literature. All the great scientists — think of the quantum mechanics folks, start naming them off — mostly Germans. Americans would go over to Germany to learn the science and bring it back. After World War Two, the United States became sort of the center of science. Why? Because we picked and chose — we brought them back. There was starvation going on in Europe after the war, and so we brought the people back that we wanted to bring back, and we essentially made the United States great in science by bringing all these other people. Wernher von Braun — they set him up in Huntsville, Alabama.