Let me know when humanity manages to construct a self sustaining interplanetary vessel with artificial gravity that can house 100 people on an ongoing basis.
A ballpark estimate for that most basic of first steps would be costing something like a trillion dollars. We would have to assemble it in orbit, you cannot launch such a large craft with rockets.
Basically, this will never happen unless the US military declassifies the supposed gravity negating field generator that is rumored to be essential to the TR 3B, which is itself rumored to exist.
You have to go all in on conspiracy theory tech like that, or magically world peace happens, we invent affordable greater than parity fusion generators, oh and entirely magically figure out how to stop climate change, and replace petrochemicals at every single stage of production in the world economy.