Risky Decisions

Sociologist says NASA's culture led to Challenger disaster

By Sandra Howe
Staff Writer

Revelations surrounding the space shuttle Challenger disaster, which occurred 10 years ago this week, shocked the nation when they first became public. But Assoc. Prof. Diane Vaughan (Sociology) has raised a host of new issues about the event in her latest book, The Challenger Launch Decision: Risky Technology, Culture and Deviance at NASA.

Like millions of Americans, Vaughan witnessed the shuttle explosion on television and followed the long, often troubling search to find out why the National Aeronautic and Space Administration had not prevented the tragedy. Suspecting organizational misconduct, Vaughan assumed investigators were correct in claiming NASA had ignored potential risks because of managerial errors and scheduling pressures.

She found that the cause of the disaster went deeper than the traditionally accepted explanations, however, and her book identifies fundamental problems in NASA's organizational structure and mindset as the root of the catastrophe.

Vaughan pieced together nine years of research for the book, relying on over 200,000 pages of interviews and internal NASA documents housed at the National Archives, in addition to her own interviews with 18 people associated with safety regulations at NASA. She concluded that NASA's process for making high-risk decisions created a structure in which conformity to the rules overshadowed concern and caution. In deciding to launch Challenger, NASA managers had not violated agency procedures as was thought, Vaughan found, but abided by them all.

Assoc. Prof. Diane Vaughan (Sociology)-"The decision to launch Challenger was . . . a mistake embedded in the banality of organizational life." (Photo by Gary Gilbert)

"The decision to launch Challenger was, incredibly and sadly, a mistake embedded in the banality of organizational life," she said. "No fundamental decision was made at NASA to do evil; rather, a series of seemingly harmless decisions were made that incrementally moved the space agency toward a catastrophic outcome."

These decisions by top NASA administrators can be traced as far back as 15 years before the Challenger disaster and altered the agency forever, Vaughan said. From the beginning of the space shuttle program, she said, NASA assumed that risk could not be eliminated. While engineers could predict performance mathematically and run tests under simulated flight conditions, they could not verify the shuttle's capability under actual ascent, orbit and descent situations. Anomalies were, therefore, expected on every mission, according to Vaughan, and a disregard for danger signals became ingrained among NASA personnel, even as imperfections went unchanged.

This mindset was evident during the controversial eve-of-launch telephone conference call described in the book, when engineers at Morton Thiokol, the manufacturer of the shuttle's solid rocket boosters, recommended that the launch be delayed due to the unusually cold weather. But Vaughan dispels the myth that the engineers predicted disaster, based on a solid engineering analysis, if the launch was not delayed. On the contrary, Vaughan shows that none of the engineers predicted catastrophe and all of the teleconference participants, including the Morton Thiokol engineers, agreed that the no-launch argument was technically weak.

The NASA managers were confronted with unprecedented conditions, according to Vaughan: NASA had never received a no-launch recommendation at such a late date; the solid rocket booster group never had such grave technical concerns so close to a launch; and the launch-day temperature at Cape Canaveral was at an unprecedented low. With nothing else to guide them, managers held to NASA's normal rigorous regulations when an intuitive argument should have been enough to stop the launch.

Later investigation proved that their intuition was correct. The below-freezing temperatures had warped a rubber O-ring seal in one of the boosters, though that, in itself, was not the fatal flaw. As Challenger gained altitude, however, an unanticipated wind shear dislodged the damaged O-ring, Vaughan said, allowing heat to escape and ignite the shuttle's huge liquid fuel tank.

"The managers were faced with conditions of uncertainty, and in such situations, people tend to fall back on rules," she said. "In the process, they expanded the boundaries of risk one more time, which created a disaster."

Though Vaughan's previous research focused on "uncoupling" in relationships, where small problems accumulate unnoticed, she sees a parallel with her Challenger research.

"If a couple starts to fight, but deny there is a problem, they will accept the fighting as normal," said Vaughan. "Before you know it, the relationship has crumbled. This is what happened at NASA. As the years passed by, they accepted more and more problems, becoming blinded to the possible harmful results of their actions."

Following the investigation, NASA took steps to prevent another space shuttle disaster, but Vaughan says risk can never be entirely eliminated. If NASA accepts risk, however, it must be aware of the escalating level of danger that comes with each decision.

"Because the space shuttle program involves experimental technology, we can never predict the outcome with certainty," she said, "and we cannot make rules for all possible conditions either."

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