How Stuff Works: How Fusion Propulsion Will Work
Shows how building a fusion-powered spacecraft would be equivalent of developing a car on Earth that can travel twice as fast as any car with a fuel efficiency of 7,000 miles per gallon.
Innovative Nuclear Space Power and Propulsion Inst
Researching square lattice honeycomb ternary carbide fuels and nuclear electric propulsion based on gaseous and liquid fuel reactors with magnetohydrodynamic power generation systems, among other things.
NERVA
The Nuclear Engines for Rocket Vehicle Applications project. Started by the Atomic Energy Commission and NASA in 1961 and cancelled in 1971 due to radiation worries and a lack of interest from NASA.
Nuclear Thermal Propulsion
Federation of American Scientists' review of the topic.
Nuclear Thermal Propulsion
A look at modern nuclear propulsion designs.
NuclearSpace
The goal is to promote the use of nuclear power in space and to further enhance the manned exploration of our solar system.