astroengine writes: "So we have a space station, now what? We've heard some rather outlandish ideas, but this is one concept a research group in NASA is taking seriously. By retrofitting the ISS with rockets, Nautilus-X will act as an interplanetary space station of sorts, including room for 6 astronauts, an artificial gravity ring, inflatable habitats and docking for exploration spaceships. When can we take a luxury cruise to Mars? 2020 by the project's estimate. It all sounds very 2001, but the projected costs of retrofitting the space station seem a little on the low side."