Endeavour helped by disaster

NASA reaction to gouge is shaped by Columbia

August 20, 2007|By New York Times News Service

While Columbia faced much more serious damage — Confronted with the same kind of problem that doomed the space shuttle Columbia, NASA officials, chastened by years of criticism and upheaval in the agency, took a markedly different approach during the current mission of Endeavour, calling on an array of new tools and procedures in order to analyze and respond to the problem.

While Columbia faced much more serious damage - a 6- to 10-inch-wide hole punched in a leading edge of one of its wings that let in searing gases during re-entry - outside officials said that NASA had taken steps far more elaborate and methodical with Endeavour than those performed during the Columbia flight.

"The comparison is night and day," said John M. Logsdon, director of the Space Policy Institute at George Washington University who served on the investigation board that looked into the Columbia disaster.

Engineers and officials will not know for sure how accurate their analysis was or whether their decision to forgo a repair in Endeavour's underside was the correct one until the shuttle is back on Earth. The landing is scheduled for tomorrow.

But in maneuvers as simple as having Endeavour perform a slow backflip to allow the crew aboard the International Space Station to photograph the spacecraft's belly, to the use of a new laser scanner - built in response to the Columbia disaster - that showed the exact shape and size of the damage, NASA officials showed the vast changes in procedures, attitude and culture of the space agency since the Columbia accident four years ago.

In both missions, a piece of foam fell from the fuel tank, damaging the shuttle, and both times NASA officials expressed confidence that there would be no peril to spacecraft or crew.

But this time, there is better reason to believe the assurances of NASA, outside experts say. For one, the piece of foam that hit Endeavour was much smaller. But also, the Columbia disaster pushed vast changes in procedure and attitude through the shuttle program. The head of the shuttle program retired and the mission management team leader transferred out of the shuttle program. New tools were developed to identify and analyze damage to the heat tiles, and senior managers began to make sure that dissenting voices could be easily heard.

Perhaps the Endeavour analysis overlooked some crucial detail, but that possibility is "very, very slight," Logsdon said. "This episode is a good example of how the shuttle program has changed."

For both Columbia and Endeavour, the falling foam did not initially worry mission managers. At a news conference Aug. 9, the day after Endeavour's liftoff, John Shannon, chairman of the mission management team, said that three small pieces of foam might have hit the Endeavour but "nothing significant."

What changed in the past four years is how NASA managers handle an event they do not consider serious.

Columbia's mission mangers never thought foam could cause catastrophic damage, and subsequent analysis reinforced preconceived conclusion. This time, mission managers knew the exact damage the foam caused.

Computer simulations indicated that the hottest gases would not flow to the bottom of the gouge and that the temperatures of the underlying aluminum skin would remain safely cool.

"We really have spent years preparing for the case we have on orbit," said Steve Paulos, manager of the orbiter project office at the Johnson Space Center. About 100 people worked on the analysis of the Endeavour gouge.

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