NEW YORK -- Internal NASA documents obtained by The New York Times suggest that the agency is downplaying the dangers posed by shuttle debris so that it can continue to send astronauts into space. But space agency officials denied yesterday that safety standards are being loosened.
The Times reported yesterday that the documents by engineers and managers for the space agency indicate at least three changes in the statistical methods used in assessing the risks of debris such as ice and foam insulation striking a shuttle during launching.
One presentation said lesser standards must be used to support accepting the risks of flight ''because we cannot meet" the traditional standards, according to the newspaper.
The Times reported that there is debate within the agency about whether the changes are a reasonable reassessment of the hazards of flight or whether they jettison long-established rules to justify getting back to space quickly.
But NASA officials said in a telephone news conference last night that although engineers have differed in their mathematical approach to analyzing the threat of launch debris, in the end they all agreed on the risk levels. The discussion was open, and all opinions were heard, they said.
More analysis is needed before Discovery can lift off, as early as May 22, the officials noted.
A suitcase-size piece of fuel-tank foam insulation was blamed for the disintegration of the shuttle Columbia as it was returning from space in February 2003.
Earlier this month, John Muratore, shuttle systems engineering manager, openly acknowledged that even marshmallow-size pieces of insulating foam from the fuel tank could doom the space shuttle under the worst circumstances. He told reporters it is a risk that NASA and the nation must accept if flights are to resume soon. He said it would take a total redesign of the tank to completely eliminate foam loss.
Muratore said last night he does not view changes in risk assessment as a relaxation of safety.