The Technology of Discovery

10Advanced US RTG Technologies in Development

Chadwick D. Barklay

University of Dayton Research Institute, Dayton, Ohio

10.1 Introduction

The invention of the radioisotope thermoelectric generator (RTG) is an enabling technology that allows spacecraft to venture to distant planets and beyond the boundaries of our solar system. Teams of researchers and scientists working at institutions worldwide direct a myriad of scientific instruments on these spacecraft and analyze the telemetry that flows back to unravel the mysteries of our universe. The discoveries associated with these missions would be impossible with more conventional power sources such as batteries, fuel cells, and photovoltaics. The successful performance of the RTGs on these missions laid the foundation for advanced power conversion technology development.

NASA’s Radioisotope Power Systems (RPS) Program makes strategic investments in dynamic, thermoelectric, and other power conversion technologies to maintain NASA’s current capabilities and develop advanced technologies. The latest NASA technology research roadmaps [1] include investments in space power and energy storage technologies, including thermoelectric materials. The development of conversion technologies in flying RTGs occurred in the mid to late 20th century. [2] NASA has made strategic investments to increase specific power to a range of 4 to 6 W_e/kg in RTGs yet that range appears to be an upper boundary [3] that remains unattainable however. The conversion ...