Confident Shuttle Crew Re-inspect Heat Shield
By Irene Klotz
HOUSTON (Reuters) – The Discovery crew used a boom-mounted digital camera to reinspect six suspect areas on the shuttle’s heat shield on Friday, but were confident the problems that led to the 2003 Columbia disaster have been resolved.
The most serious area of concern is on Discovery’s carbon-tipped nose, which must withstand temperatures hot enough to melt steel when the shuttle plunges back into the atmosphere prior to landing.
“That’s the main thing we’re looking at,” said flight director Tony Ceccacci.
NASA extended Discovery’s mission by one day, to 13 days, in order to add a third spacewalk to test a heat-shield repair technique.
Astronauts said they were happy with the spacecraft’s performance — good news for NASA since more trouble could force the space agency to scrap the shuttle program.
“At this point we’re really satisfied. We haven’t had many problems with Discovery,” pilot Mark Kelly said during an in-flight interview. “
The primary purpose of Discovery’s flight is to test a second redesign of the ship’s fuel tank. During Columbia’s launch, insulating foam from the tank broke loose and smashed into the shuttle’s wing. The spacecraft disintegrated over Texas 16 days later when fiery atmospheric gases entered the breach as Columbia glided toward landing in Florida.
On the last shuttle flight a year ago, foam again fell from the fuel tank at launch, although none struck the spacecraft.
NASA has spent $1.3 billion on two fuel tank redesigns and other safety upgrades. Based on Discovery’s performance, NASA is gaining confidence the work was successful.
Since the shuttle launched on Tuesday, NASA has used an array of cameras and sensors to inspect Discovery and so far turned up no major problems. In addition to the nosecap inspection, NASA also wanted the crew to get close-up pictures of two semi-rigid cloth strips that are sticking out from surrounding ceramic tiles on the shuttle’s belly.
Engineers were determining if the protruding strips pose a potential for overheating the shuttle’s heat shield during re-entry to the atmosphere.
During Discovery’s flight last year, spacewalkers made an unplanned outing to pluck two protruding strips that could have triggered a heat shield failure.
“We’re still collecting data but it sure looks good, so we’re obviously very pleased,” said shuttle commander Steve Lindsey.
NASA needs to resume regular shuttle flights to complete construction of the half-built International Space Station before the fleet is retired in 2010.
Discovery linked up with the space station on Thursday and on Friday attached an Italian-built cargo module to it carrying more than 5,000 pounds (2,272 kg) of equipment and supplies.
In addition to food and clothing, the module holds a freezer for experiment samples, a European Space Agency incubator to grow plants in space and a new oxygen generator so the station’s crew size can eventually be doubled to six.
Once unloaded, the module will be filled with trash and broken equipment from the station and placed back in the shuttle for return to Earth.
Discovery also brought German astronaut Thomas Reiter to the station to join current station crew members Jeffrey Williams and Pavel Vinogradov for a six-month stay.
(Additional reporting by Jeff Franks)