Nuclear electric Mars Payload Transfer Vehicle

The conceptual design of a mercury ion propulsion system for an unmanned Mars Payload Transfer Vehicle is discussed. In the present scenario, a two-loop alkali-metal Rankine cycle power conversion system produces about 7.5 MWe to power the thruster and onboard systems, and the ion engine provides a thrust of 245 Newtons. With an initial mass of 750 tons in LEO, the ion propulsion system is projected to deliver a payload of 383 tons into Mars orbit, yielding a mass fraction (based on the ratio of payload to initial mass) of 0.51. To deliver an equivalent payload, a chemical propulsion system utilizing a Hohmann transfer is found to require a total mass in LEO of 1479 tons and to yield a mass fraction of only 0.20. 9 references