After the Challenger accident in 1986, Richard Feynman found that people at NASA disagreed about the odds of losing a Shuttle. “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.” At 1 in 100,000, he noted, “one could put a Shuttle up each day for 300 years expecting to lose only one.”
His appendix to the presidential commission’s report ends: “For a successful technology, reality must take precedence over public relations, for nature cannot be fooled.”