Innovative Nuclear Space Power: "Why Nuclear Thermal Propulsion?
Because of its high performance potential, nuclear thermal propulsion (NTP) could be utilized for manned missions and cargo transport to the moon or mars, unmanned explorations of the outer planets, and earth orbit transfers of satellites.
Nuclear propulsion can provide a greater specific impulse (Isp) to reduce the time for a manned mission to Mars from 600 days to about 200 days. In reducing this time, nuclear propulsion will reduce the risk to astronauts from cosmic radiation to say nothing of the other health and psychological benefits from shorter mission times."