The PEGASUS drive: A multi-megawatt nuclear electric propulsion system

Electric propulsion systems have not been seriously considered for use with large spacecraft due to the lack of suitable electric power source to drive them. However, recent efforts to develop megawatt-class space power sources show such systems to be technologically feasible. A multi-megawatt lightweight nuclear electric power plant driving an electric propulsion system, such as a megawatt class magnetoplasmadynamic (MPD) thruster, would make this quite an attractive propulsion system for extended missions. PEGASUS, a power generating system for use in space, is one such multimegawatt power system that would enable missions of almost any conceivable duration and scope. The PEGASUS Drive is the coupling of this nuclear electric power system with a 6 MWe MPD thruster. The power system has a maximum power output of 8.5 MWe. The MPD thruster requires 6 MWe to provide spacecraft propulsion and 1.5 MWe are available for mission-specific tasks and experiments. The balance of power generated is used to operate the power system. The size and mass limitations of the STS are of prime consideration in the design of this system to allow the collapsed system to be placed in lower earth orbit by two shuttle missions. The main system (19,120 kg) employing a shadow shield would require one launch and the balance of the four-pi shield (27,830 kg) would occupy the second launch. Development of this power system could be completed by the mid 1990's and the system available near the turn of the century