> there was not a single fatality This strikes me as the same reasoning that Feynman criticized in the Rogers report: > The argument that the same risk was fl

> there was not a single fatality This strikes me as the same reasoning that Feynman criticized in the Rogers report: > 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. [1] Just because no one died doesn't mean that the practice is safe. It might be safe, just like it could have been with the shuttle, if the engineers had designed the o-rings to withstand erosion. In that case you'd have tests and a spec for how much erosion is safe. Similarly, unless there's a guideline on acceptable rate of mechanical failures (which the article suggests there isn't) "there was not a single fatality" is not an acceptable proof of safety. [1]: http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/rogers-commission/Appendix-F.txt http://science.ksc.nasa.gov/shuttle/missions/51-l/docs/roger...