[Spaceships] getting into orbit without superscience?

[Fred Brackin]

Originally Posted by Varyon

If you're in atmosphere, even if you aren't using a ram-rocket design I think your exhaust would contain free neutrons, which would interact with the atmosphere to generate secondary radiation. I'd still count that as "radioactive exhaust" - ?

Free neutrons don't constitute any sort of long-term radiation hazard. All of the major components of Earth's atmosphere are still harmless after absorbing a neutron. The neutron hitting a nucleus but not being absorbed does transfer some energy but it's pennyante stuff. You're in much more danger from the heat of the exhaust.