Currently my solar sats are produced in 1s

But if I upgrade my ninite factory, will there be any effect on these sats
however, there speed should go to 0.5s

and if I upgrade it once more then 0.25s and as the system rounds it off, it should become 0.0s?

They become insta:

Construction Time : 00h 00m 00s

Yeah, what kick said. Basically, you type in the number that you want, and they are there. Well, that's implying that you have enough resources to buy them.

But only if the number is under 1000. That's a real pain.