NASA clears Discovery to fly on Tuesday

CAPE CANAVERAL, Florida (Reuters) - NASA managers cleared the space shuttle Discovery for launch on Tuesday after a prolonged debate about whether its fuel tank was safe enough for flight, officials said Wednesday.

The space shuttle Discovery rolls out to Launch Pad 39A with lightning in the area at NASA's Kennedy Space Center in Cape Canaveral, Florida August 4, 2009. REUTERS/NASA/Handout

In the end, the vote was unanimous to proceed with launch at 1:36 a.m. EDT on Tuesday. Discovery is scheduled to spend 13 days in orbit on a mission to deliver supplies and spare parts to the International Space Station, a $100 billion project of 16 nations that is nearing completion after more than a decade of construction.

“It wasn’t a contentious discussion,” said Bill Gerstenmaier, NASA’s associate administrator for space flight. “We let everyone state their opinions. No one chose to appeal the decision, but there were definitely some differing opinions.”

Foam falling off the shuttle’s fuel tank during launch has been an ongoing safety issue since the 2003 Columbia accident. The shuttle was hit by a falling chunk of foam that damaged its heat shield. The ship broke apart as it flew through the atmosphere for landing 16 days later, killing all seven astronauts aboard.

Several redesigns of the tank have greatly reduced the amount of foam shed during launch, but concerns remain. During last month’s launch of shuttle Endeavour, the tank lost foam from a new area. Because the tanks are not retrieved, NASA has not been able to determine what caused the foam loss.

Engineers suspect a problem with the adhesive used to bond the insulation to the metal tank.

Technicians drilled nearly 200 samples out of Discovery’s tank to test whether its foam was properly applied, then patched the holes. Workers also checked the foam on the tank earmarked for NASA’s final mission of the year in November.

“We think we have intelligently picked areas to show that the adhesion was good,” said shuttle program manager John Shannon.

Some engineers pushed for additional tests of Discovery’s tank, which would have delayed launch until October. Managers decided no more tests were necessary.

NASA, however, will have the Discovery pilots fire their ship’s steering rockets longer than usual after reaching orbit to provide more light for photographing the tank after it is jettisoned.

“I think we’ll have better pictures than we’ve had in the past,” Shannon said.

NASA has six missions remaining to outfit the station before the shuttle fleet is retired. After that, the station will be serviced by smaller Russian, European and Japanese vehicles which cannot carry bulky experiment racks and heavy spare parts.

Discovery’s seven-member crew includes first-time flier Nicole Stott, who will replace Tim Kopra as a flight engineer aboard the space station.

Editing by Jane Sutton