Shuttle mission extended to give bonus day at station
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: July 30, 2005
NASA's mission management team today extended the shuttle Discovery's flight by one day, giving the astronauts more time to assist and resupply the international space station's two-man crew, and concluded the shuttle's heat-shield tiles and insulation blankets are fit for a normal re-entry Aug. 8.
But management team chairman Wayne Hale said engineers planned to take one more day to fully assess the health of the orbiter's wing leading edge panels and another 24 hours after that to fully analyze two other minor problems to make sure they won't affect Discovery's handling and heating during re-entry.
"The imagery analysis from the launch phase has been completed," Hale told reporters late today. "And the damage assessment on the orbiter is in full swing. Today, a day ahead of our schedule, I'm pleased to report the tile and (insulation) blankets have been formally cleared by the engineering team. A few pock-marked tiles, a little gouge at the base of the nose landing gear door, a thermal blanket that had billowed out on the side below the commander's window, all of those items have been formally assessed through rigorous engineering models in great detail and found to be acceptable to fly home as is."
Hale said he expects engineers to formally clear the shuttle's reinforced carbon carbon wing leading edge panels Sunday, leaving only one issue to be resolved: The status of two so-called "gap fillers" seen protruding between tiles on the underside of the shuttle.
Gap fillers are inserted between tiles to provide a protective cushion. They can occasionally shake free during launch and end up extending beyond the surface of the surrounding tiles. During re-entry, the shuttle depends on a smooth, or laminar, flow of air over the underside tiles and anything that extends up into the flow can trigger turbulence. Turbulence, in turn, can cause higher heating across downstream tiles and affect the handling of the shuttle.
Engineers do not believe the gap fillers in question pose a threat to Discovery, Hale said, they are simply being thorough in their analysis.
"It's been a great day today," Hale told reporters. "We had an outstanding EVA (spacewalk), the crew is performing in just an awesome manner, it's admirable how well they’re doing. The orbiter is performing nearly flawlessly, we have no new funnies on our list to look at.
"Today we tested in space, in orbit, the thermal protection system, two of the methods of (heat-shield) repair we've developed ... and both of them performed very well. I got very good reports from the designers who watched those tests today on the ground and evaluated the outcome. They worked very well, we're very pleased and it bodes well.
"It is one thing to do tests on the ground, it is another thing entirely to be able to do a test actually in space and get real data in the real environment on how these materials will perform."
Hale said the astronauts had conserved enough electrical power, primarily by limiting the use of a booster fan, "to formally declare we have the capability to extend the mission a day. ... This will allow the crews to get more work done, more (equipment and supply) transfers."
The shuttle's three fuel cells produce electricity by combining liquid hydrogen and oxygen. A by product of the reaction is water, which is transferred to the space station. By staying an additional day, Discovery's crew will generate enough extra water to supply the station crew for 20 days.
The Discovery astronauts are also going to leave a few laptop computers behind and provide additional assistance to their station counterparts.
A Russian Progress supply ship is scheduled for launch Sept. 8 but NASA's plans to launch another shuttle supply mission in mid September are in limbo because of the external tank foam insulation problems seen during Discovery's launching.
NASA only has two shuttle launch windows left this year, one in September and a short four-day window in November.
Space station program manager Bill Gerstenmeir said the space station's current crew, and replacements expected to arrive in October aboard a Russian Soyuz spacecraft, will have more than enough supplies to make it through the rest of the year even if the shuttle stays grounded into 2006.
"The plan is we're going to have a Progress at the first part of September, Sept. 8, and that looks fine and it's on track and then there's another Progress later," he said. "We're fine from a consumables standpoint all the way through the end of the year. We're in very good shape. ... We're going to get a lot of water from the shuttle here, which will put us in very good shape."
See the Status Center for full play-by-play coverage.