Documents indicate that NASA is shifting its standards for debris damage to the shuttle, The New York Times reported Friday, but a spokesman for the space agency said the shifts should not be interpreted as a loosening of safety requirements.
The newspaper cited internal documents including one saying that lesser standards must be used to determine acceptable risks, “because we cannot meet” traditional standards.
The article’s technical assertions were “factually correct,” NASA spokesman Bob Jacobs told Reuters. But he added, “The assertion that we’re loosening standards is not.”
“We take all safety assessments very seriously. We have taken well-documented strides in changing management structure and safety reviews, and we’re not going to fly the orbiter until we feel that it is safe to fly,” he said.
The three-ship shuttle fleet has been grounded since Feb. 1, 2003, when Columbia broke up over Texas, killing all seven crew members. Independent investigators determined that foam insulation from the shuttle’s external fuel tank hit the craft’s wing on launch, causing a breach that allowed superheated gas to penetrate the ship on re-entry.
NASA is preparing to return the shuttle to flight, with a planned May 22 launch for the ship Discovery. The space agency has made several design and management changes aimed at improving safety.
Jacobs confirmed the newspaper’s report that tests showed a higher-than-desired failure rate for the reinforced carbon-carbon material that makes up the leading edge of the shuttles’ wings.
However, he said this did not represent a loosening of standards. Instead, he said, it shows a need to “learn to fly safely in that environment.”
The Times cited internal memos that purportedly show at least three changes in the statistical methods used in assessing the risks of debris like ice and insulating foam striking the shuttle at launch.
Jacobs said extensive work has done into reducing such risks. “Debris-shedding was one of the paramount return-to-flight issues and we’ve made significant changes — to the design of the external tank, to the application of foam — all to make flight as safe as possible,” he said.
Experts consulted for the Times article did not suggest that Discovery is unsafe, but the newspaper said “a small but forceful minority say the worry that NASA is repeating a practice that contributed to the Columbia disaster: playing down risks to continue sending humans into space.”
NASA has undergone a period of institutional soul-searching since the Columbia’s disintegration, especially after investigators found the agency had a “broken safety culture” that was the underlying cause of the accident.
The agency’s new chief, Michael Griffin, said this week he might consider letting the shuttle return to flight even if an independent panel has not finally approved some safety improvements that Columbia’s investigators deemed essential.
An independent commission meant to monitor the 15 safety recommendations for the return to shuttle flight has yet to give final clearance to eight of the recommendations.
