posted 06-12-2007 07:15 PM               

To quote Bill Harwood, CBS/Spaceflight Now:

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The concern is that hot air during re-entry could damage the underlying graphite epoxy structure of the left-side Orbital Maneuvering System rocket pod. During the 15 minutes or so of peak heating, the temperatures on the OMS pods reach 700 to 1,000 degree Fahrenheit. While engineers do not view this as a life-or-death sort of problem - shuttles have safely returned to Earth with much more serious OMS pod damage - there are enough unknowns to prompt caution.

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As it turns out the material used in the blanket will make the fix relatively straight forward, writes Harwood:

quote:

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"If you take this blanket and you pull it up like the wind is hitting it, it'll stay up like that," [Mission Management Team chair John] Shannon said. "It's got some memory. But when you push it back down, it stays down. That's something we're kind of counting on. We think the astronauts will be able to go out there and just push this right back down. They're working right now different ways to attach it to the blanket that's laying beside it or maybe to attach it to the tile face that's in front of it."

The repair work is expected to take 90 minutes to two hours to complete. An astronaut, his feet anchored to an extension on the end of the shuttle's robot arm, will be maneuvered back to the left-side OMS pod and push the flap down.

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posted 06-12-2007 07:24 PM               

The two primary techniques being looked at are being referred to as "staple" or "stitch." These photos (courtesy someone@jsc.nasa.gov, though B-roll of the tests from which these photos were taken have aired on NASA TV) show the tools involved.

The blunt-end needle used to "sew" the blanket is usually used to resize the EMU's arms and legs. In this application, it is equivalent to a darning needle.

The remaining three photos show the "staple" technique, using a tool from the on-board medical kit:

posted 06-13-2007 11:54 AM               

Cheers,

posted 06-13-2007 10:21 PM               

An astronaut positioned by the shuttle's robotic arm will first use his gloves or, if desired, a scraper tool intended for other thermal protection system (TPS) repairs, to pat down the insulation. The material is such that it is expected to remain flat (in relation to the surrounding area) rather than fold back up.

Mission Management Team chair John Shannon demonstrates the 3M Precise Multi-Shot Disposable Skin Stapler. The device carries 15 staples; eight of the the staplers are planned to be brought outside for use during the repair.

The crewman will then apply a double row of staples using a device from the shuttle's medical kit. According to Mission Management Team chair John Shannon, these are not your average office supply staples, but act more like fish hooks once inserted.

Lastly, the spacewalker will insert nickel-chromium pins, also designed for TPS repairs, through the insulation into the thermal tiles that it borders, to attach one to the other. To assist with inserting the pins, the crewman will have a dental tool from the shuttle's medical kit.

Shannon shows the dental probe.

Though this method has been selected as the preferred repair, NASA plans on Thursday to test the configuration on the ground for its tolerance to reentry-level heating, as well as test the currently-exposed OMS pod graphite epoxy honeycomb skin under the same thermal conditions.

According to Shannon, if the repair proceeds on EVA 3 at the time when they expect it now to happen, than Olivas will perform the fix.

posted 06-15-2007 03:51 PM               

And with that, the repair is complete. As the above screen captures from NASA TV illustrate, the repair was deemed by Danny Olivas and ground controllers as successfully implemented.

posted 06-16-2007 11:16 AM               

Thank you from those of us who couldn't watch it live.