Description: Many NASA missions are limited or impossible due to the lack of a suitable power supply. Many objects of interest can’t use photovoltaics. The outer planets and their moons and other small bodies are too distant from the sun. Polar Lunar craters are in shadow, the Martian poles have long winters and features such as lava tubes are dark. A number of new missions would be enabled with the availability of a small, reliable non-solar power supply with a long life.NASA has qualified the Radioisotope Heating Unit (RHU) as a one watt heat source for warming electronics and batteries. This RHU is present on most NASA missions. Hi-Z has developed a small power supply (RPS) that uses the RHU to produce 40mW of electrical power for 20 years. The 40mW RPS has been demonstrated to JPL and has a TRL of 5. JPL and DOE recommend the RPS be transferred from JPL to DOE for further development. The transfer is expected to take a year. Hi-Z, in partnership with Aerojet Rocketdyne, proposes to use this waiting period to advance the RPS TRL from a 5 to a 6 prior to DOE’s acceptance of the technology.