Science, as George Bernard Shaw writes, “becomes dangerous only when it imagines that it has reached its goal.”12 Before the Challenger accident, NASA had successfully launched shuttle missions despite the erosion of the O-rings. Before the Columbia accident, numerous shuttle launches had succeeded despite the shedding of foam. Each success reinforced a belief in the status quo. Each success fostered a damn-the-torpedoes attitude. With each success, what would otherwise be considered unacceptable levels of risk became the new norm.
