“In 2013 or 2014, we’ll make clusters of 200-kilowatt engines to give us something close to a megawatt of electricity, and deploy them with a very high-powered solar array. This will be a robotic reusable “space tug” that can refuel or reposition satellites, or even send packages to the Moon at a much lower price.”
I hope this works for them! This will make is so all we need for interplanetary exploration is to get to low earth orbit and the rest of the way will be paved by solar or nuclear powered VASIMIR.
I like this one because it’s in the works and imminent. Not some iffy thing some twenty years out.