We all likely remember (or have read about) the tragic explosions of the space shuttles Challenger (1986) and Columbia (2003) and the deaths of all crew members in both accidents. As you may recall, NASA’s investigation into both explosions uncovered problems that had been long known in the space shuttle program ranging from faulty O-ring seals (Challenger) to foam insulation falling off during launches (Columbia). These problems, or defects, were widely known and expected to occur. NASA accepted these defects as part of the space shuttle launch process. Questions were raised, to be sure, but the questions lacked the kind of disciplined attention necessary to stop the problems from occurring. This has come to be known as the “normalization of defects”.
