Feynman s Summary of the Challenger Disaster
Richard Feynman’s appendix to the Roger’s Commission report laid a groundwork that essentially indicted the culture at NASA, especially upper management in its lax attitude towards safety. ... He begins his observations by noting the large discrepancies between NASA engineers’ estimates for a probability of failure as 1:100 and management’s assessment as 1:100,000. ... Feynman questions, “What is the cause of managements fantastic faith in the machinery? ... He questions NASA’s logic of accepting risk with no previous failures as an indication that it is safe to continue flying the shuttle with no remedy to the problems, “The argument that the same risk was flown before without failure is often accepted as an argument for the safety of accepting it again. ... There were many instances where NASA’s decision making process went wrong. To begin with, in the SRBs, Feynman estimated that with due care, the boosters would probably expect a failure in no fewer 1:100, but not greater than 1:1000. NASA’s management claims that the reliability of the SRB are much higher than that. Feynman points to the fallacy of NASA management’s claim that, “these figures are for unmanned rockets but since the Shuttle is a manned vehicle "the probability of mission success is necessarily very close to 1. ... ” This is not rational thinking on NASA’s part. ... Feynman addresses the disparaging numerical probabilities between management and engineers, “It would appear that, for whatever purpose, be it for internal or external consumption, the management of NASA exaggerates the reliability of its product, to the point of fantasy. ... As Feynman points out, the O-rings are not designed to erode or have blow-by result, “They are warnings that something is wrong.