Re: Is this not the RTG that some of us have planned to send to Pluto?
I'm fairly certain that nuclear power would have to be used. I have no idea when a space elevator could be built, but the engineering seems just barely within reason. NASA has done less practical things, like successfully flying an aircraft with forward-swept wings, and failing to fly a small-scale model of the Hyper-X. Sometimes they were successful, sometimes they weren't, but at least they tried.