Two NASA officials who objected to the agency's recent decision to launch the next space shuttle on 1 July will not appeal the decision, they explained on Wednesday. They reason that the crew could take shelter on the International Space Station in the event of an emergency.
On Saturday, NASA announced it would attempt to launch Discovery on 1 July, barring bad weather or unforeseen technical glitches. The decision came after a two-day meeting with 250 managers and engineers.
All of the 39 top shuttle managers signed the Certificate of Flight Readiness, which certifies the shuttle is ready to launch. But two officials, chief safety and mission assurance officer Bryan O'Connor and chief engineer Chris Scolese, added caveats to their signatures because of the persistent risk that foam could come off the external fuel tank and strike the shuttle orbiter (see NASA sets shuttle launch date despite objections).
The biggest known concerns are the 37 small ice/frost foam ramps that cover metal brackets outside the external tank. On previous flights, small pieces of foam have come off those ramps. NASA plans to redesign the metal brackets so they do not need foam insulation, but an interim fix was not ready in time for this flight.
So Scolese crossed out the statement, "I concur with proceeding with this mission" in the Certificate of Flight Readiness. "[I] was no go for the flight because I believe we should repair it and we have a path to repair it," Scolese said at a NASA teleconference on Wednesday.
Still, he noted in the certificate that he would not appeal NASA's decision because if the shuttle were damaged after launch, the seven crew members could take shelter aboard the International Space Station (ISS) until a rescue shuttle could pick them up. "Given the decision and the fact that we do have many options available to us to protect the crew . . . the community is not against the decision to fly," he explained on Wednesday.
O'Connor registered his reservations in the same way. On the certificate, he wrote: "I am no go based on loss of vehicle risk (ice frost ramps). Based on appeal to administrator I have no intention to appeal his risk acceptance and concur with proceeding with mission."
O'Connor said that if the astronauts thought the mission was too risky or if he personally felt that the crew's lives were threatened, he would try to appeal the decision to fly. But since the station could be used as a safe haven, he feels the crew will be safe.
"I think we're just barely into the unacceptable risk area," O'Connor explained. NASA defines "unacceptable" risk as any problem that could cause catastrophic damage to an orbiter over the entire lifetime of the shuttle programme, which is due to end in 2010.
The ISS has enough supplies, including oxygen, food and water, to support the seven shuttle astronauts and the station's two crew members for about 80 days. But if a rescue shuttle were sent to the station, it would be most likely be afflicted with whatever problem damaged the first shuttle because NASA would not have time to fix the problem.
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