The Crew of the Columbia: In Memoriam
Richard P. Feynman's Minority Report to the
Space Shuttle Challenger Inquiry
Conclusions: (abridged)
If a reasonable launch schedule is to be maintained, engineering often cannot be done fast enough to keep up with the expectations of originally conservative certification criteria designed to guarantee a very safe vehicle. In these situations, often with apparently logical arguments, the criteria are altered so that flights may still be certified in time. They therefore fly in a relatively unsafe condition, with a chance of failure of the order of a percent.
Official management, on the other hand, claims to believe the probability of a failure is a thousand times less.
This difference has unfortunate consequences, the most serious of which is to encourage ordinary citizens to fly in such a dangerous machine, as if it had attained the the safety of an ordinary airliner.
For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.
~ Richard P. Feynman 1986
