File:KSC-05-S-00214 (ksc 071005 114 lyons-11).webm

English: MS. STILSON: Here's another good one from Daryl in Jal. Of all the issues that NASA has had to address for STS-114, which was the most difficult to solve and which was the most crucial to fix? MR. LYONS: 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. So we spent a lot of time working that problem. And we actually added several modifications to the External Tank to preclude foam from coming off and also to preclude ice buildup, as the heaters I mentioned earlier. We put heaters on to prevent ice buildup. So that was a real tough one for us to tackle. Also, tile repair on orbit. We call it on-orbit tile repair. And that presented real challenges because, obviously, you're in a vacuum in space, which makes applying material very difficult. And we also deal with extreme temperatures, both high and low. And, finally, the astronaut actually has to leave the Shuttle and the spacewalk to go perform the repairs. 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.