Development of a Small-Low Power Radioisotope Thermoelectric Generator Using the General Purpose Heat Source

Radioisotope thermoelectric generators (RTG) are a critical enabling technology for space exploration. Only the U.S., Russia, and China have shown the capability to produce RTGs for use in space, with the European Space Agency funding an effort to develop a small americium-241-based RTG. In the U.S., the only RTG currently available is the 110 W
e
multi-mission radioisotope thermoelectric generator, but an estimated 242 W
e
Next Generation RTG is under development. While Russia and China can produce RTGs for space, there are significant political challenges related to partnering and using their systems. This challenge creates a considerable gap for missions that may only need 10s of watts of electricity but cannot efficiently accomplish their goals with batteries or solar power. If such a system were available for partnering and use, we believe the demand for these missions would increase significantly. Here, we present the progress in developing a 14 W
e
small low-power (SLP) RTG fueled by a single General Purpose Heat Source (GPHS). This design is projected to have a specific power of nearly 5 W
e
/kg, the second-best specific power of any RTG produced (GPHS-RTG being first). It is even better than the projected specific power of the Next Generation RTG. This system will utilize ruggedized silicon germanium modules produced by RGS Development B.V. and a novel RTG design developed by the University of Dayton Research Institute. It is envisioned that this RTG would enable a new class of very long-term, low-power missions that want to operate in areas where solar power is challenging, such as missions to the outer planets or shaded areas of the lunar surface. Development of the SLP-RTG from concept to the current design state will be discussed.