NASA has a critical, long-term need for deep space power systems based on the decay of radioisotopes and the resulting thermal energy produced. These systems are critical for flagship missions to explore the outer solar system for both spacecraft and rovers. The current radioisotope converters based on thermoelectric technology are inefficient and have low mass specific power. Radioisotope thermophotovoltaic (RTPV) energy converters have the potential to be an attractive alternative to competing radioisotope energy converter technology. RTPV has the potential to provide comparable or higher mass specific power, at similar (probably lower) conversion efficiency. RTPV and the associated technology proposed on this project have a number of potential non-NASA government uses. Radioisotope power sources based on thermoelectrics have been used for terrestrial military applications for many years. For example, they are used to provide power for deep sea monitoring instruments deployed by the Navy. They have also been used in remote locations for monitoring stations. RTPV could be a credible alternative in all these applications. Small radioisotope batteries based on TPV have been proposed and are being developed for a number of military sensing applications. The technology being developed on this project has the potential to benefit these ongoing efforts.