The Gemini space missions took about 18 months from approval to first flight. All we need now is a man rated Dragon capsule and some engine replacements. Not a big deal. Also, NASA already has a contract with Bigelow Aerospace for a new crewed module. It is going to be attached to the ISS, but is designed to be a free floating station. Just put the Bigelow module in orbit, and we have a new space station.
“The Gemini space missions took about 18 months from approval to first flight.”
Sorry, that was another era and another America.
Today they Gemini program wouldn’t even be approved. Every space capsule design would have to be large enough for one woman, one minority, one gay, one transgendered - and probably one white male just to operate all those silly knobs and switch things.