It has been 30 years since the Challenger crew tragic death. The reason was worn O-ring with safety margin three times the face value. Costing less than $ 100 including installation.
As the great physicist of our time winner of the Nobel Prize in 1965 Richard Feynman (1918-1988): In NASA lacked the pessimists! and added: Nature can not be fooled!
Pessimists even though people are not popular, but very necessary, and everywhere. Sure, not without reasons, a management and performers are often deceived by past successes.
Let us not slacken their vigilance engineering, and as a bona fide employees of various organizations, let us ask ourselves whether we have done everything for total security?
Good luck to you all and good nights before the start!