The Stirling engine is a candidate for use with isotope power systems. In the references below, Bents et al. (1992, 1992, and 1991) discuss the application of free-piston Stirling convertors to dynamic isotope power systems (DIPS). DIPS could have applications to a variety of unmanned deep space and planetary exploration missions. The RTG (radioisotope thermoelectric generator) is the power source currently available for these mission requirements. The Stirling convertor is able to achieve higher efficiencies at these lower power levels, thus, allowing a significant reduction in the amount of isotope required. Thermal photovoltaic power systems are beginning to sound like a very attractive possibility for isotope power, but are still in an early stage of development.

Radioisotope Stirling generators have been studied for the Pluto Fast Flyby Mission (Schock 1993). The Stirling Technology Co. (STC) of Richland, Washington has been developing a ten watt Stirling power convertor for radioisotope applications (Ross et al. 1991 and Ross et al. 1994) and has reported over 14,000 hours of endurance testing for one engine. STC uses flexure technology to achieve non-contact bearings in their small power convertors.

References:

Bents, D. J.; McKissock, B. K.; Rodriguez, C. D.; Hanlon, J. D.; and Schmitz, P.C. (1992) "Dynamic Isotope Power System Design Considerations for Human Exploration of the Moon and Mars," Proceedings of the 27th Intersociety Engergy Conversion Engineering Conference.

Bents, D. J.; Schreiber, J. G.; Withrow, C. A.,; McKissock, B. I.; and Schmitz, P. C. (1992) "Design of Small Stirling Dynamic Isotope Power System for Robotic Space Missions," NASA TM-105919

Bents, D. J.; Geng, S. M.; Schreiber, J. G.; Withrow, C. A.; Schmitz, P. C. and McComas, T. J. (1991) "Design of Multihundred-Watt Dynamic Isotope Power System for Robotic Space Missions," Proceedings of the 26th Intersociety Energy Conversion Engineering Conference

Ross, B. A.; Tingey, G. L.; and Holliday, J. C. (1991), "Conceptual Design of a Long-Life 10 Watt Stirling Generator Set," Proceedings of the 26th Intersociety Energy Conversion Engineering Conference, Vol. 5, pp 186-191

Ross, B. A.; and Ritter, D. D. (1994), "Performance of a Second Generation 10-Watt Free-Piston Stirling/Linear Alternator Generator Set," Proceedings of the 29th Intersociety Energy Conversion Engineering Conference, Vol. 4, pp. 1917-1921.

Schock, A., (1993), "Radioisotope Stirling Generator Options for Pluto Fast Flyby Mission," Fairchild Space and Defense Corporation, Germantown, MD

Last updated: Wednesday, May 3, 1995

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