re: Correction
To get the same ridership as motor vehicles, you would have to launch 5.1 million shuttles per day. That would require 1,364,735 nuclear powerplants, each producing 4-gigawatts of power, continuously producing LOX/LH2 fuel via electrolysis. Even one percent of this ridership would require 13,647 nuclear powerplants. And THAT is alot of water to exhaust into space. Talk about energy- and material-limited space travel !!!
Solar energy. Gotta use it.