Mission extension likely
BY WILLIAM HARWOOD
STORY WRITTEN FOR CBS NEWS "SPACE PLACE" & USED WITH PERMISSION
Posted: July 7, 2006
With a one-day mission extension considered a done deal, the Discovery astronauts are using a high-resolution camera to inspect a half-dozen areas of the shuttle's heat shield for signs of damage during launch Tuesday. Engineers at the Johnson Space Center, meanwhile, are starting to think about whether the astronauts might need to remove one or two protruding gap fillers during a third spacewalk expected to be added to the mission now that engineers know Discovery will have enough power to support the extra day in orbit.
Lead flight director Tony Ceccacci said NASA's Mission Management Team, which has the final say in such matters, likely will complete its analysis of Discovery's heat shield Saturday, after evaluating high-resolution photographs taken today by a camera on the end of a long boom attached to the shuttle's robot arm.
"The smallest damage of concern that we have is on the order of .08, eighty thousands of an inch, and that camera is certified to be able to show us that level of damage," Steve Poulos, manager of the space shuttle projects office at the Johnson Space Center, said before launch.
Lisa Nowak, Stephanie Wilson and pilot Mark Kelly are inspecting six regions of interest on the shuttle based on imagery collected during launch and the day after. One site is on the shuttle's reinforced carbon carbon nose cap, three are on two RCC panels on the ship's right wing leading edge and two involve protruding gap fillers, one up near the nose of the shuttle and the other back near a propellant feedline access door.
"There's a team working on the possibility of them having to remove the gap fillers or cutting the gap fillers in the two locations I mentioned previously," Ceccacci said. "We're just getting prepared. That way, if we have to do something we're ready to go. If we did have to do that, most likely it will be on EVA 3 (the third spacewalk)."
That excursion by spacewalkers Piers Sellers and Mike Fossum is planned for next Wednesday. By coincidence, the primary goal of the outing is to test wing leading edge repair techniques.
Sellers and Fossum plan to stage their first spacewalk Saturday, evaluating whether the long inspection boom on the end of the shuttle's robot arm can be used to support astronauts if heat shield or other repairs are ever needed. A second spacewalk is on tap Monday to repair a stalled transporter that is needed to move the station's arm from point to point along a huge solar array truss. Of the three spacewalks, the second is most critical because station assembly cannot proceed until the transporter is repaired.
"After we get the focused inspection data today and get all the pictures down, the imagery folks will take a look at it and I'm sure by sometime this evening, maybe eight hours or so, they'll have enough information to determine if they're concerned about those gap fillers. ... Probably tomorrow for sure, at the MMT, they'll have the final decision."
Astronaut Steve Robinson removed two gap fillers during Discovery's flight last summer, riding on the end of the space station's robot arm to gain access to the shuttle's underside. Sellers or Fossum could ride the station arm to reach a protruding gap filler near Discovery's nose, if engineers decide it must be removed. But the shuttle arm and inspection boom likely would be required if the gap filler near the feedline access door toward the back of the orbiter is deemed a threat.
"The one over by the ET door, we'd have to get on the boom to do that," Ceccacci said. But engineers believe gap fillers that far back on the belly are not a much of a threat as protrusions near the nose.