WEBVTT

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Here's another good one from Daryl in Jal. Of all the issues NASA has had to address for

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STS-114, which was the most difficult to solve and which was the most crucial to fix?

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Well, there were several challenges and issues, obviously. One of the big ones was foam coming off the External Tank and possibly damaging the orbiter.

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So we spent a lot of time working that problem.

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And we actually added several modifications to the External Tank to preclude foam from coming off and also to preclude ice buildup,

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as the heaters I mentioned earlier.

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We put heaters on to prevent ice buildup. So that was a real tough one for us to tackle.

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Also, tile repair on orbit. We call it on-orbit tile repair. And that presented real challenges because, obviously,

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you're in a vacuum in space, which makes applying material very difficult.

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And we also deal with extreme temperatures, both high and low. And then finally, the astronaut

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actually has to leave the Shuttle and the spacewalk to go perform the repairs.

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So that was a real tough one for us. And both of these areas we've made great progress and we're ready to go safely fly.

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