Oasis Lower Spaceport

Models! Wow!
Hmm. Where did you find the Space Shuttle Models?
I've always thought they looked really neat just the Orbiter+ET pair, but it's so hard to find a model that'll allow that

Anyways, must've been some hard work "frankensteining" the model kits like that!

Speaking of which, that's the big reason NASA never took up A.C. Clark's championed idea. I don't know about Martin Marietta, who you said came up with it, but I know A.C. Clark was a visionary... But not an engineer.

After Apollo and the Shuttles were made, NASA lost it's guts, all of it's bravery and courage that had made it great, so something like on-orbit cutting, etc. that would be required was too risky for them to develop.

The alternative is to completely redesign the External Tank to include hatches and stuff, though that, too, would be quiet a challenge. And no matter what, it'd need a layer of more permanent insulation, that would add a lot of weight on top of everything else that'd be needed.

And after all that, a space station... With no windows Inflatable habs almost make more sense.

Though burning the ET's over the Indian Ocean, was certainly a terribly huge waste, just a few dozen MPH from orbit... They would make excellent storage space for the ISS.