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by mannykannot 848 days ago
My position is not that a different or more thorough presentation of the argument would have made no difference (though, personally, I doubt that it would have), it is that Tufte's argument (and the aphorism it launched, "charts killed the Challenger crew") greatly exaggerates the significance this narrow issue and tacitly blames the people who were trying their best to save the day.

In Tufte's version, the meeting in question was the tipping point where it all went wrong, while the reality is that it was the last forlorn chance for NASA to to escape, by the skin of its collective teeth, from an overdue disaster that had been years in the making. As the Rogers Commission revealed, NASA had, in an environment of over-promising and political horse-trading, developed a culture in which deviance was normalized, and it was not ready to handle evidence contrary to the semi-official dogma of shuttle flights being routine and established events.

I'm not in a position to say how Boisjoly felt so sure the launch would end disastrously, but I can make a few guesses. I think it is quite possible that he gradually became aware, and then concerned, that the O-rings did not fare well in cold weather, as the data trickled in one launch at a time. I can imagine that when it became clear, a few days before the launch, that the temperature would be below freezing, his concerns sharpened into near-certainty that things would go wrong. One does not need a theory of what, precisely, was happening to the O-rings to suppose that if below-normal temperatures led to problems, then nothing good could come from an exceptionally low one. Perhaps he was too close to the data; I can also imagine that this seemed so clear to him that he never imagined his managers - who were also engineers - not also seeing it, instead clinging to older estimates of risk. I further imagine that he was completely blindsided by the somewhat rhetorical and sarcastic response, which went something like "are we supposed to wait until July?"

IIRC, Boisjoly anticipated that the joints would fail catastrophically immediately after the boosters were ignited, and for a minute afterwards he experienced profound relief...

Despite this all coming out in the Rodgers Commission report, NASA followed the same normalization of deviance path after it became apparent that ice was damaging the tiles, which is one reason why I doubt that better charts would have stopped the launch.

1 comments

(Just wanted to say thank you for the thoughtful followup. I was hoping you would, since it sounded like it’d be interesting. And when you phrase it like you did, it does sound absurd to offload the blame onto whoever was presenting the charts. Enjoy the rest of your Sunday.)
Thanks! You might find Wayne Hale's (Space Shuttle Program Manager or Deputy for 5 years, a Space Shuttle Flight Director for 40 missions) 10-year retrospective on the Columbia crash interesting:

https://waynehale.wordpress.com/category/after-ten-years/

Also, I recall reading somewhere that the chairman of the Columbia Accident Investigation Board, Admiral Harold Gehman, decided to conduct a test to see if the piece of foam seen hitting the leading edge could have broken it. As, at the time, it had not been decided to end the shuttle program, this was not an easy decision, as it meant sacrificing an essentially irreplaceable spare part. What finally convinced Gehman to go ahead was the fact that a great many NASA engineers firmly believed it could not possibly have been the cause.