On the way to the Jovian system, a nuclear thermal transfer vehicle refuels in a Mars-orbit near Martian moon Phobos, in this artist's rendering. This steady-state system could provide a reliable foundation for the exploration and eventual colonization of the Solar System. This image produced for NASA by Pat Rawlings, (SAIC). Technical concepts for NASA's Exploration Office, Johnson Space Centre (JSC). (NASA Media Archives). Buy this as a superb wall poster, a canvas print or a framed print.