Critical design features of thermal-based radioisotope generators: A review of the power solution for polar regions and space

As one special type of sustainable energy source, radioisotopes have extremely high energy densities. Electrical generators using the decay heat from these radioisotopes can provide long-lasting power when other types of energy, such as solar or chemical energy, are not available. Starting from the 1960s, radioisotope generators were safely used in numerous space and terrestrial missions, and have powered systems from interstellar spacecraft to lighthouses along the arctic coast. This work reviewed the generator development and critical components that constitute a functional system. Started with a brief generator history, the paper focused on technological aspects including fuel manufacturing, energy conversion elements, thermal insulation, structural materials, prototype measurements, future improvements, and concluded with the safety aspects for both space and terrestrial applications. Radioisotope generators are one example of using nuclear energy in a peaceful way to benefit human be-ings. Plutonium fuel productions were resumed and accelerated in the United States and americium fuel research was actively sponsored by the European Space Agency. It is promis-ing that more and more high performance generators will be used in future land and space missions. •The history and radioisotope fuel source technology.•The thermal-to-electrical energy conversion methods and devices.•The generators' insulation, structural supports, and radiators.•Measurement results from different technology prototypes and futuristic directions.•The social and political challenges of using the generator in space and terrestrial missions.