Capabilities and technical issues regarding the Stirling radioisotope generator

The National Aeronautics and Space Administration (NASA) Glenn Research Center (GRC) has been active in the development of Stirling power conversion technology for over 25 years. Currently, a free-piston Stirling power convertor is being developed for use in a long-life Radioisotope Power System (RPS) to power NASA deep space and planetary surface missions. The Stirling Radioisotope Generator (SRG) design requirement is for greater than 100,000 hour (11.4 year) life providing over 100 watts dc to the spacecraft. The Department of Energy (DOE) is responsible for providing radioisotope power systems for NASA missions, and has managed the development of a free-piston Stirling power convertor for this application. Because of the ability to operate in a broad range of environments (vacuum of deep space or atmosphere of Mars), the SRG is being considered for a variety of missions. This paper will briefly describe the role of the NASA GRC in advancing the Stirling technology for space power systems, give examples of technical areas where in-house expertise has been utilized, and highlight some of the contributions that have been made. This paper will also present some examples of how the power system might be used to enhance the capabilities of missions, describe the status of the overall project, and address some critical technical issues.