I'm starting to wonder if the NASA guy is supernatural too and not just not-Kaguya.
Technically, neither of them are actually that supernatural.
The only thing 'supernatural' about Tsukasa is the fact she imbibed the immortality elixir from the Kaguya tale... at least, I'm pretty sure that's all it is. Everything else about her can be explained away by lots and lots of experience honing various skills over the more than thousand years she's been implied to be alive
since consuming that elixir. Any time we think she's read minds, it's actually Nasa not realizing he was speaking aloud, because she sure as shit hasn't demonstrated an ability to know what he's thinking most of the time- there's certainly points where she has no idea what he's mulling over, and I guarantee she'd be blushing like crazy if she could hear his thoughts at many points.
The only possible 'supernatural' thing about Nasa that I can think of that I think comes up later is that
he might be a reincarnation of someone she met in the past during her extremely long life, but never allowed herself to get all that close to originally.
no lunar waifu to say "I love you" to
ITS NOT FAAAAAAAAAAAAAAAAIR
Not lunar. Perfectly normal human.
Who just happens to be immortal because elixir from that moon princess story that was supposed to be destroyed. At least, that's my best guess as to her origin as someone that watched the entire anime.