innerspace travel, can't go more than 100km high because of the glass marble/firmament.
Checkmate
Rainbows aren't possible without a firmament, there's some kind of glass in the sky. Not a dome though it looks like a marble and light is inverted as it passes through giving the sky a dome appearance.
also the center of gravity is around the center of the Earth, if it's concave with the sky as a glassy marble in the sky the center of gravity of earth should be within the marble - and it is!
https://www.lockhaven.edu/~dsimanek/hollow/tamarack.htm
This isn't clownworld - saying something has been debunked isn't the same as debunking it.
Same way you get natural rainbows - glass in the sky + reflective water vapour. Try making a rainbow inside with just a sprinkler - it's impossible unless you 1st run the light through some glass type substance.
I think it's still possible to land on the moon(it's tiny and so is the sun), that NASA moonlanding was fake of course.
Didn't Q say moon landings are real?, I don't think flying through plasma would count as a moon landing.