This artist's concept shows a nuclear electric-propelled vehicle, about the size of a football field, firing banks of ion thrusters in order to circularize its orbit around Mars. Assembled in Earth orbit, the transfer vehicle with its 10 megawatt power plant could transport 130 metric ton payloads to Mars in 6 1/2 months, and could repeat its circuit every 52 months. This artwork was done for NASA by Patrick Rawlings of SAIC. SAIC has been working with NASA's Lewis Research Center on possible mission designs which might allow for more energy efficient trips to Mars.