by Tony the Misfit
The real story behind 7 Challenger myths
[Via Boing Boing]
Related to the 25th anniversary of the Challenger disaster—7 myths about Challenger debunked by former mission control operator James Oberg.
[More]
Challenger is, along with 9/11, one of those events where I know almost exactly what I was doing.
I was doing my postdoc in Boulder then and had gone to Aspen with some other researchers to ski. I was on a ski lift when, about late morning, I heard something had happened with Challenger and I went back to the room – the only one in our group to do so. (Just as I was the only one at my workplace who spent thee day watching the news on 9/11. Everyone else just kept working.) So I know I did not see it live.
I broke into tears watching the replay of the end of Challenger – I still do whenever I see replays –and hoped, even then, that they were not awake afterwards. I did not ski again that day.
I remember watching the Challenger hearings, although I can not recall if I saw Feynman’s experiment with the O-ring live or not. I do remember the poor engineer who had been picked to be the scapegoat in front of the hearing. I remember hearing about people changing their ‘hats’ to make a decisions, as though what an engineer had to say would change when he thought as an administrator.
Of these 7 myths, the only one I would have agreed with is the explosions – the somewhat pedantic explanation that it was not really an explosion may be true but people have little other experience on what to call it. People do not really know the difference between detonation and deflagration. Simply saying ‘it came apart’ does little justice to the absolute destruction of the event. Using explosion as a shorthand does not seem mythic to me.
But so many of the other myths are to find some bigger reason other than simple human failure – it was Reagan’s fault, it was the EPA’s fault. The idea that there is really nothing we can do – that, like Jurassic Park, scientists and engineers will always fail and that danger can not be reduced – is also a deeply destructive myth.
What I do recall is that the solid boosters used had, at that time, a failure rate of about 1 in 50. The Challenger was the 25th Shuttle flight – 2 boosters per flight. (Overall, the Shuttle has a failure rate of 1 in 65 missions, suggesting that engineers did get better at reducing risk by making changes in the design.) The problem was more that flight management had adopted a ‘well it did not blow up last time, it will not blow up this time’ attitude towards dealing with many of the problems that arose with the complex Shuttle. Thus they had really ignored the entire purpose for Criticality 1 issues.
Because, if they had really done that, it is likely that fewer Shuttle flights would have been made. There was a lot of redundancies built into the system that allowed all sorts of things to be survived. We know about the problem with the low temperatures. But that was a contingency that we did know about and could discuss.
In fact, it is very possible that they would have made it through this event also – even with the burnt O-rings – except that the Challenger experienced the strongest wind shear pressures ever. These forces acted to break the frail protection that still existed in the solid rocket boosters. Without the wind, the Challenger might have avoided disaster, even with all the engineering mistakes.
And that is really the important lesson. As we gain better knowledge of the natural world around us, then we can do a much better job working with it. Designing a system that can even fail and still work was a marvel, until it hit a natural part of our world outside our previous knowledge. Now that we know, we can take precautions.
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