Hybrid nuclear light bulb - Nuclear-pumped laser propulsion for advanced missions

A hybrid "nuclear light bulb" gaseous core reactor that can radiantly transfer energy to a propellant or alternately activate laser action is proposed for advanced space missions. The propellant mode would be employed in the phases of the mission requiring a higher thrust. However, for the bulk of the travel, the propellant would be turned off and the ultrahigh specific impulse laser mode of operation would be employed. The concept is reviewed, research and development issues are identified, and steps necessary for a feasibility demonstration are discussed.