In ESA’s policy, the safety assessment of radioactive materials used in any space mission is managed through the development of independent analysis and the implementation and maintenance of a safety culture.
A valuable case study for understanding the practical application of the implementation of this policy, and for demonstrating Europe’s commitment to the safe and responsible use of NPS in space, is the Argonaut lunar mission.
This is a multi-robotic mission to land a large spacecraft on the surface of the Moon to deliver supplies and infrastructure to support exploration, the return of samples from the Moon, and the long-term sustainable use of the Moon through international cooperation.
To keep the spacecraft’s engines and electronics within a temperature range that will ensure their operation during the 14-day lunar night and temperatures down to -150°C, the spacecraft contains Radioisotope Heating Units (RHU). The heat is generated by the natural decay of radioisotopes, in the case of the Argonaut mission americium-241, a ceramic form of uranium-doped americium oxide, encapsulated in a system of physical barriers to avoid the risk of radioactive release under nominal launch conditions and to minimize the risk of dispersion in accident environments.
This mission paves the way for future missions and contributes to the advancement of space technology. In addition, close cooperation with international organizations, governments and space agencies ensures that best practices in nuclear safety are shared and adopted globally, promoting transparency, and building trust between countries and organizations, laying the foundation for the safe use of NPS in space.
