SCCAQ Energy, LLC (SCCAQ) in collaboration with Temple University and Infinia Technology Corporation (ITC) proposes to develop a Reliable Stirling Convertor (RSC) prototype free-piston Stirling (FPS) engine designed to address NASA needs for space power applications. This STTR proposal is specifically addressed to Topic T3 (Space Power and Energy Storage), with an emphasis on Subtopic T3.01 (Energy Transformation and Multifunctional Power Dissemination). The RSC offers multifunctional versatility that can efficiently convert thermal energy from a wide variety of heat sources into useful distributed electric power. Examples include capturing waste heat from a rocket exhaust, utilizing concentrated solar power, and conversion of nuclear heat energy from either radioisotope decay or fission energy. The reference design starting point will be the Technology Demonstration Convertor (TDC) that was developed by Infinia Corporation in the 1999 to 2006 time frame as a Radioisotope Power System (RPS). SCCAQ proposes to significantly upgrade the TDC design using newer technology and innovations to increase efficiency and robustness, while reducing size and weight. The proposed effort will be supported by SEEE lab of Temple University and will heavily leverage support from Infinia Technology Corporation.