Why not nuclear power?

[Bearware]

22. I would bet on some form(s) of more primitive molten salt "reusable rockets" before MMNF's

One limit on current molten salt designs is nuclear qualified piping and other materials are certified for maximum temperatures well below what the reactors could easily reach without turning the salt into vapor. Elysium Industries chose sodium chloride for the low temperature melting point and cost. They are trying to get a factory produced MSFR licensed as soon a possible so they are not trying advanced features such as super-critical CO2 or extensive fuel reprocessing.

The MSFR I mentioned is a fast reactor and does not need the same level of fuel processing that thermal reactors do. Because it is molten salt they can inject new fuel in any desired composition any time. The limited processing they do is documented in the last video below. The initial load of fuel is about 70 tons and they burn about 1 ton/per year. The two videos were made far enough apart in time that one can see how the design is evolving.

Hopefully we will get an administration in 2020 that understands Climate Change mitigation needs a super-Manhattan Project(s) on nuclear power as well as the equivalent in research on the same. Multiple designs are a good thing in the beginning.