Debate ends in decision to launch

Discovery on the launch pad. NASA file photo.

After a four-hour debate, NASA engineers voted not to delay the Oct. 23 launch of Discovery, despite warnings from the NASA Engineering and Safety Center, which recommended rolling back to the VAB and replacing three slightly damaged panels on the wing leading edges.

The reinforced carbon composite panels have slight cracks in the silica carbide coating, which keeps oxygen from burning through the panel on re-entry when temperatures reach 3,000 degrees.

"The worst case is that we would lose some of the coating off the panel during the first part of re-entry," said shuttle program manager Wayne Hale, after engineers with competing positions debated the problem during Tuesday's Flight Readiness Review.

Experience and testing indicate that if the coating came off during re-entry, Discovery would still land safely, he said.

"Weighing against the mitigation we have, we think it's an acceptable risk to go fly," said Hale.

Since May, the NESC has warned that slight damage of the coating means the panels should be replaced or tested more thoroughly. Replacement would delay Discovery's launch by two months to roll back to the Vehicle Assembly Building.

"There are tests that should be run before we fly," said Ralph Roe, NESC director.

However, even after the NESC raised its concerns, no NASA engineers voted against going forward with the launch.

"We were all 'go'," said Bill Gerstenmaier, NASA's space operations chief.

Gerstenmaier explained that similar panels were removed after STS-114 and found to be slightly damaged, but the orbiter landed safely.