At 01:43 PM 9/23/2005 -0700, you wrote:
>Dr Richard Feynman (known not-exactly-accurately as "the guy who 
>discovered the O-ring problem") wrote his own addition to the official 
>report on the Challenger accident.  In it he warns that judging safety in 
>terms of "Well it's worked so far" doesn't prove what it seems to.   A 
>google on "feynman report challenger" turned up the report on the first 
>hit.  The first two paragraphs follow:
>
>  * * *
>
>It appears that there are enormous differences of opinion as to the 
>probability of a failure with loss of vehicle and of human life. The 
>estimates range from roughly 1 in 100 to 1 in 100,000. The higher figures 
>come from the working engineers, and the very low figures from management. 
>What are the causes and consequences of this lack of agreement? Since 1 
>part in 100,000 would imply that one could put a Shuttle up each day for 
>300 years expecting to lose only one, we could properly ask "What is the 
>cause of management's fantastic faith in the machinery?"
>
>We have also found that certification criteria used in Flight Readiness 
>Reviews often develop a gradually decreasing strictness. The argument that 
>the same risk was flown before without failure is often accepted as an 
>argument for the safety of accepting it again. Because of this, obvious 
>weaknesses are accepted again and again, sometimes without a sufficiently 
>serious attempt to remedy them, or to delay a flight because of their 
>continued presence.

I particularly liked the burning of an o-ring seal 1/3 of the way through
(for basically unknown reasons) described as a 3:1 safety factor.

That's the sort of garbage you'd expect from marketdroids, not rocket
scientists.

>Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog  Info for designers:  http://www.speff.com
->> Inexpensive test equipment & parts http://search.ebay.com/_W0QQsassZspeff


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