Why NASA's making the right decision

HOUSTON - At first glance, NASA's decision to possibly launch even if a sensor glitch reappears suggests that the space agency was wrong two weeks ago to postpone the launch. However, the two decisions actually are very different, and indicate how much NASA's safety culture has improved.

Had NASA decided two weeks ago to ignore the glitch, it would have been a decision based on instinct alone. Had that instinct proved right (that is, nobody dies), it would have begun the process of betraying the hard lessons of Challenger and Columbia. The odds are that the hardware flaws would not have had disastrous consequences — but the decision to fly anyway, in the face of them, could well have.

The decision to launch this time, in the event of a sensor "hiccup" of a very specific type, will be made in the full sunlight of massive amounts of investigation, analysis, and cold-blooded calculations of safety principles. It may or may not have happy consequences (anything can happen, especially in space), but it will be fully consistent with the best practices of hazardous operations. These standards have in the past led to safe space flights, and past occurrences of forgetting such principles have been at the root of NASA’s worst space disasters.

Plugging the "culture hole"
Columbia and its crew were lost not so much as a result of a hole in the heat shield, as from a hole in NASA's safety culture. The hazards of impacts on the shuttle’s underbelly from debris off the fuel tank were "instinctively" understood, space officials thought, but a full range of verification testing had never been performed. The result of the particularly large impact when Columbia was launched was not thoroughly investigated — it was deemed too much trouble to get better pictures of the impact area, much less ask the astronauts to take a spacewalk to look closely — and so self-imposed team-wide ignorance became a shroud to hide behind in avoiding inconvenient worries.

The same mindset, an assumption of instinctive "all right" when testing and experience didn’t validate such views, also destroyed Challenger. Would the booster seals hold at the unusually low temperatures? Nobody had shown they would, but managers under pressure from an unrealistic launch schedule turned engineering judgment on its ear by demanding skeptics prove that the seals would not hold.

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