What has been learned from the Challenger and Columbia tragedies?
Both of these accidents prove to us the problem with complex designs. In the case of Challenger, the SRB did not suffer a catastrophic failure, but the leaking hot gas interacted with the rest of the vehicle, which resulted in the loss of Challenger and her crew. In the case of Columbia, the External Tank did not suffer a catastrophic failure, but a piece of insulation broke loose and damaged the leading edge of Columbia’s wing leading to the loss of Columbia and her crew. In fact, as a launch vehicle the Shuttle accomplished the objective of getting to space safely, but due to the complex interactions during ascent suffered a catastrophic failure during reentry. The Space Shuttle has flown 113 times and has never suffered a catastrophic failure of any of the major propulsion elements! What we have learned is that highly complex vehicles are difficult to understand and fail in ways we cannot predict. The safest vehicle we can produce uses the highly reliable propulsion elements that we
