Shuttle Discovery cleared for launch
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: July 3, 2006
NASA managers Monday night decided to press ahead with a Fourth of July launch of the shuttle Discovery, weather permitting, after engineers concluded the loss of foam insulation from an external oxygen feedline posed no threat to the orbiter or its crew.
The decision was announced after an evening Mission Management Team meeting to review a hurried analysis of the foam loss incident and its potential impact. Officials said a boroscope inspection and close-up photographs of the bracket in question gave engineers confidence no additional foam will break away and that no dangerous ice will build up on the remaining insulation that could pose an impact threat to the shuttle's fragile heat shield.
Bill Gerstenmaier, NASA's chief of spaceflight operations, said the decision was based on sound engineering analysis and was not the result of "go fever."
"I think we ask ourselves that question all the time, are we doing something here or are we pushing too hard, are we trying to make this flight occur? And the answer is no. The answer is, we've laid out the data, we've looked at it calmly, we're ready to go fly because we're ready to go fly. We're not ready to go fly because of some launch window or some other condition. I think the teams have done a very good job of avoiding the tendency to try to get launch fever."
And so, with forecasters calling for a 60 percent chance of acceptable weather, engineers plan to begin refueling DIscovery for its third launch try in four days around 4:45 a.m. Liftoff from pad 39B at the Kennedy Space Center is targeted for 2:37:55 p.m. The launch window closes exactly five minutes later.
Should launch slip to Wednesday, forecasters are predicting a 60 percent chance of showers and cloud cover that would force yet another delay. The launch window Wednesday opens at 2:07:13 p.m. and closes at 2:17:13 p.m. The preferred launch time is 2:12:13 p.m.
The triangular piece of foam that broke away from a bracket supporting a 17-inch-wide liquid oxygen feed line was found on the surface of Discovery's mobile launch platform MOnday during a standard post-fueling inspection after a launch delay Sunday.
The piece weighed just .0057 pounds - .091 ounces, or about the weight of a penny - and was roughly half of the mass that would result in a 1-in-100 chance of catastrophic damage to the shuttle's heat shield.
Sources said Discovery commander Steven Lindsey and his crewmates - pilot Mark Kelly, flight engineer Lisa Nowak, Piers Sellers, Mike Fossum, Stephanie Wilson and European Space Agency astronaut Thomas Reiter - told managers Monday morning that they favored delaying launch one day to Wednesday to give engineers time to make a close-up, hands-on inspection of the bracket insulation.
Steve Altemus, the newly named director of engineering at the Johnson Space Center, and Terrence Wilcutt, director of safety and mission assurance at the Texas space center, also said they supported additional inspections.
The engineering debate hinged on three broad questions:
"Those views showed the foam was structurally intact," said Gerstenmaier. "There's no loose foam in there, it all looks fine and the structure is in good shape."
He said the camera operators "did as good an inspection or probably a better inspection than they could have if they'd gotten out there with a platform."
The aerothermal analysis showed the bracket had more than enough foam remaining to easily handle the expected heating from Discovery's high-speed ascent. Finally, engineers concluded the remaining insulation should prevent any excessive buildup of ice.
"We've satisfied all the criteria we need," Gerstenmaier said. "We're ready to continue on with tanking."
Lindsey and his crewmates were scheduled to go to bed Monday evening at 7:05 p.m., before the final decision was announced. But Gerstenmaier said the astronauts were tied into the meeting via telephone and that Lindsey did not voice any objections to the decision to proceed with flight. Altemus and Wilcutt also attended this evening's meeting and they, too, agreed with the decision.