That 'shuttle' isn't a
real one, but a very well-done mockup that used to be at Kennedy Space Center's visitor center (it was moved once they got the flown orbiter, Atlantis). I got inside it in 2009 the last time I was there and was impressed. The cockpit area is compressed a bit and the cargo bay area changed to allow people inside, but overall they did a great job. It was called, "Explorer" at KSC but I've read that the name might be changed. I saw this orbiter mockup again at Houston in September, it's sitting in the spot depicted in the artist rendering right now (and strongly lashed down against potentital hurricanes). I agree that the climate isn't the best for an outdoor exhibit but this is one heck of a consolation prize for Houston not getting a space-flown orbiter. But like the Saturn V, I agree that someday there'll have to be a total restoration to counter the ravages of an outdoor display. Such a shame they can't get it indoors, but such a massive building would be needed, I don't think it's realistic to expect one to be built anytime soon (if ever).
More info here:
http://www.collectspace.com/news/news-050213b.html