Discovery Astronaut Easily Makes First In-Flight Shuttle Fix
Thursday, August 4, 2005
HOUSTON, Aug. 3 -- As if reaching for a receipt at an ATM, spacewalker Stephen Robinson on Wednesday gently plucked two strips of protruding heat shielding from the bottom of the space shuttle Discovery, completing the first in-flight shuttle repair with fingertip ease.
Cameras operating from the shuttle's sensor boom and from Robinson's helmet provided spectacular views of his historic journey, as he first swooped out from Discovery's side on the end of a 55-foot crane and then curled beneath the orbiter to find and remove the two "gap fillers."
"It's coming out very easily," he said of the first one, shaped like an outsize guitar pick. Ten minutes later, using "probably even less force," he said, he removed the second one, about as big as a pair of raffle tickets.
At Mission Control, NASA handlers let out a collective sigh of relief. Officials had predicted the repair would be relatively straightforward, but "when we sent them out there to actually do it, I had a whole different level of concern," said Paul Hill, lead shuttle flight director.
The two gap fillers, which could have led to potentially hazardous hot spots on Discovery's underside during reentry, had seemed to be the last outstanding concern blocking officials from clearing the shuttle for its scheduled landing on Monday.
But Hill said teams of specialists were also considering a second unscheduled spacewalk to remove or repair a frayed and billowing piece of thermal "blanket" that has started to come loose below the port-side window where mission commander Eileen Collins will sit when she brings the shuttle home.
The blanket is not a heat hazard, as reentry temperatures on top of the shuttle never come close to the 2,300 degrees Fahrenheit that the underside must endure.
What engineers are worried about is a swatch of blanket that may tear away during reentry and cause damage. Wayne Hale, deputy shuttle program manager, said NASA wind-tunnel experts planned to run tests overnight Wednesday on impacts from 0.05-pound pieces of blanket, about the size of the afflicted area's outer layer. Final determination on another spacewalk will probably be made on Thursday, he said.
The thermal blanket, like the offending gap fillers and several large pieces of foam insulation that broke away from Discovery's external fuel tank during liftoff last week, were launch casualties that NASA tried hard to eliminate after the Columbia disaster on Feb. 1, 2003, grounded the fleet for 2 1/2 years.
Failure to resolve these problems, especially the shedding of foam debris, has prompted NASA to ground the fleet again while engineers figure out what went wrong and try to fix it. Officials have said that NASA must resolve the foam and gap-filler problems before the shuttle flies again.
Hill acknowledged the seriousness of the shuttle's shortcomings but noted that "everything since the first 10 minutes of the mission has gone perfectly, and most of the stuff that has gone perfectly is stuff we didn't even know how to do 2 1/2 years ago."
That appeared to be the case Wednesday. Without the imaging systems developed after the Columbia disaster, Mission Control would never have found the errant gap fillers and would never have undertaken a repair on the belly of the orbiter.