Advanced propulsion for future planetary spacecraft

Advanced propulsion concepts are evaluated for unmanned exploration class missions to the outer planets. Spacecraft propulsion requirements for these missions are compared with those for previous missions. A major improvement in performance above that offered by current systems is needed to deliver the payloads required by these missions in an acceptable trip time. Advanced pump-fed space storable and cryogenic propulsion systems are evaluated. Nuclear propulsion options considered include the solid core, particle bed, gaseous core, nuclear pulse and nuclear electric concepts. The results of this study reaffirm the superiority of nuclear electric propulsion for this mission category.