Wednesday, August 20, 2008

Lessons from Challenger Disaster

The Challenger Disaster is a good case study of the importance of efficient engineering communication (and the perils of inefficient data presentation).

"Information designer Edward Tufte has used the Challenger accident as an example of the problems that can occur when information is presented unclearly. He argues that if Morton Thiokol engineers had more clearly presented the data that they had on the relationship between cold temperatures and burn-through in the solid rocket booster joints, they might have succeeded in persuading NASA managers to cancel the launch. Tufte has also argued that poor presentation of information may have affected NASA decisions during the last flight of the Columbia"

Edward R. Tufte, Visual Explanations:
[p.78]: “...a lack of visual clarity in arranging evidence is a sign of a lack of intellectual clarity in reasoning about evidence”

[p.52]: “Failure to think clearly about the analysis and the presentation of evidence opens the door for all sorts of political and other mischief to operate in making decisions. For the Challenger, there were substantial pressures to get it off the ground as quickly as possible... Had the correct scatterplot or data table been constructed, no one would have dared to risk the Challenger in such a cold weather.”

[p.53]:”...there is a great difference between giving orders to a mathematician or a philopher and giving them to a merchant or a lawyer; and demonstrated conclusions about natural and celestial phenomena cannot be changed with the same ease as opinions about what is or is not legitimate in a contract...” -- Galileo Galilei, Letter to the Grant Duchess Christina of Tuscany, 1615

Remembering the Mistakes of Challenger:
"The teleconference resumed and NASA heard that Thiokol had changed their mind and gave a recommendation to launch. NASA did not ask why. ‘That was stupid on our part, that was dumb,' said Lovingood. 'We should have said 'give us your rational for changing your mind' but a guy sits in a meeting, that is a good for launch meeting and he doesn't stand up in front of the train to stop it, he's go. No one stood up, so everyone was go for launch."

Lessons learnt:

* Engineers should learn how to present technical information clearly (read Tufte)

* Managers should have a basic understanding of risk (like what safety factor is, how safe launch probabilities are calculated)

* Customers should not intimidate subcontractors (duh!)

* Customers should not only question decisions that are against their wish, but also decisions that are in line with their desires

Copy of telefax sent to Kennedy and Marshall centers by Thiokol detailing the company's final position on the January 28 launch of mission 51-L. Source:

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