NASA tackling leak, crack repairs on Discovery

Fri, 12 Nov 2010

Washington - NASA was planning to tackle at least one of two repairs on the space shuttle Discovery later Friday, with no new launch date in sight, a spokesman for the US space agency said.

Discovery, the fleet's oldest spacecraft set for its final voyage, was grounded last week during the launch countdown after a fuel line leak was discovered.

In the meantime, NASA engineers have also found two 23-cm long cracks in the external fuel tank that is jettisoned into the ocean right after lift-off.

Spokesman Allard Beutel said the repairs in the leaking fuel line were planned to begin later Friday, after engineers met to make sure the repair plan covered all contingencies.

But the cracks inside the external fuel tank were another matter. They were discovered as engineers peeled back a crack in the foam insulation on the outside of the tank to reveal the root cause of the foam break.

NASA has dealt with such cracks in its history. "But we have done repairs before at the manufacturing plant, never at the launch pad," he said.

A special enclosure would have to be built over the crack, and a new layer of foam would have to be applied afterward, Beutel said.

"They are really taking their time to set this up. The manufacturing plant people have to come to Kennedy," Beutel said, referring to the launch pad at the Kennedy Space Center at Cape Canaveral, Florida.

The two cracks were found on one of 108 aluminum ribs that support an empty space inside the external fuel tank that separates the liquid oxygen tank at the top and the liquid hydrogen tank at the bottom.

The crack occurred during the November 5 fueling, due to the super cold temperatures of the fuel, Beutel said.

"It's just a matter of how long it will take. That's why we don't have a new target launch date," Beutel said.

The next launch window spans November 30 to December 6.

Discovery's problems in its 26th year of flying are the latest for the shuttle fleet as NASA winds down the legendary space shuttle program. NASA officials have not ruled out a delay of the launch until next year.

Such a delay would force postponement of the Endeavor shuttle launch, which had been scheduled for late February.

The Discovery mission is to deliver the last major US contribution to the International Space Station (ISS) - an extra room - along with supplies, including a human-like robot known as Robonaut 2, the first-such robot ever sent to space.

After the shuttle fleet is retired, astronauts will travel to and from the ISS on Russian spacecraft.

Source: Earth Times.
Link: http://www.earthtimes.org/articles/news/353315,leak-crack-repairs-discovery.html.