Will Nuclear Power Put Humans On Mars?

Antimatter propulsion, solar and magnetic sails all make great stories, but such futuristic concepts don’t do anything to get humans out to the moon, or Mars, or to various local comets or asteroids within the foreseeable future. So when planners at NASA begin to examine space-travel goals beyond low Earth orbit, beyond 2005 when the International Space Station is scheduled to be complete, they are faced with making bigger, brawnier and incredibly more expensive versions of the chemical rockets in use today. Either that, or consider a demonstrated technology that was abandoned almost 30 years ago: nuclear rocket engines.