The ISS weighs over 460 tons. The amount of propellant required to move that thing out of Earth orbit would be so substantial as to be impossible. The most powerful rocket ever, the Saturn V, could move a maximum of 155 tons to low Earth orbit, and of course they are retired. Falcon Heavy can only move 62 tons to low Earth orbit. The shuttle could carry up 32 tons. Even the Space Launch System will only supposedly lift 95 tons to LEO. As far as power goes, every rocket now available is pathetic compared to the Saturn V. My generation had the best Rock, and the best Rocket Ships.