[Lazamataz]

If the disc is indeed at least several football fields in diameter, and presumably several hundred if not a thousand or more feet above the ground, it doesn't seem credible to me that so much construction work could have been completed in only the two days between the time that Mark first saw the disc and when he meets his team inside the facilities surrounding the disc. That to me seems more like many months' worth of work, if not years, even it were a top national priority given unlimited federal funds and resources.

The disks are only a few meters in diameter. Such priority is given to this project that the structure is completed in the time mentioned, but perhaps I should extend it a little.

[Yo-Yo]

The disks are only a few meters in diameter.

Aha! That makes much more sense that a building can be built around it, then. As I said, I had no idea how large the discs were, and assumed they were much larger based on previous stories.