. . . As to where they filmed the hangar deck scenes, I figured that they built the foyer in a large stage area that isn't in the current stage with the life-size shuttle model. In TIS when they go to the foyer, the camera cuts and they are now in the foyer. In JTB, the camera is already next to or in the foyer.
Given the apparent distance between the foyer set and the shuttle mockup, it does seem more likely that those scenes were shot on the adjacent Stage 10, which was normally used for planet exteriors and one-time interior sets built for a specific episode.
. . . Of course this does raise the question - what do they need
all that empty space for anyway? Surely the pilots aren't that bad! Maybe it doubles as other functions...basketball tournaments? Court Martial hangings? Perhaps they flood it occassionally and that
's where the mysterious swimming pool is!
Or maybe they run freezer pipes across the deck and turn it into an ice skating rink?