Advanced Radioisotope Power System for Electric Propulsion Missions

Abstract

The increased interest in NASA exploration missions to the outer planets has spurred a revival in interest in applications of radioisotope power to propulsion for the spacecraft. This concept requires a closely coupled systems analysis of the power conv ersion, power management and distribution (PMAD) and the electric propulsion subsystems because the overall mass of the system is extremely constrained to meet the trip time and science/payload mass targets. This paper describes the results of such an ana lysis and the resulting integrated radioisotope electric propulsion (REP) system. Elements of the REP system have been identified and a description of the TRL levels and hardware status of each of these elements is provided. A detailed mass estimate of t he system is used to calculate the overall REP system specific mass (alpha). Mission studies conducted by NASA have indicated target values of approximately 150 kg/kWe are required for the REP system. A comparison of the REP system with those targets is made and recommendations are made for technology maturation activities that will prepare the REP system for flight opportunities in the 2008/2009 timeframe.