Controller Development for the Dynamic Radioisotope Power System

The Dynamic Radioisotope Power System (DRPS) is the next generation in radioisotope power systems (RPS). DRPS utilizes a Stirling convertor to replace thermoelectric generators currently in use, thus increasing the thermal to electric power conversion from 6% to 20%. This increase in power more than triples the energy utilization of the General Purpose Heat Source (GPHS), which are utilized as the fuel for most current nuclear powered space missions. The reciprocating motion of Stirling convertors requires a more sophisticated control system. This controller must synchronize four pairs of Stirling convertors, minimizing vibration while maximizing performance with an architecture that is single fault tolerant. Aerojet Rocketdyne (AR), an L3Harris Technologies Company devised a control scheme that will reliably govern the stroke of each convertor, ensuring robust control within a safe operating range. Additionally, AR developed a physics-based Stirling model to accurately predict the controller’s ability to maintain stroke control and evaluate other key performance parameters. This technology significantly increases power available for new space missions, while decreasing fuel consumption and demonstrating the reliability of reciprocating power conversion systems.