How NASA’s Nuclear Rockets Will Take Us Way Beyond Mars

NASA-backed fusion engine could cut Mars trip down to 30 days:

"The proposed Fusion Driven Rocket (FDR) is a 150-ton
system that uses magnetism to compress lithium or
aluminum metal bands around a deuterium-tritium fuel
pellet to initiate fusion. The resultant microsecond
reaction forces the propellant mass out at 30 kilometers
per second, and would be able to pulse every minute or
so and not cause g-force damage to the spacecraft's
occupants."

See:

http://www.theregister.co.uk/2013/04...ast_mars_trip/