The growing international interest in “going to the Moon to stay” is seen as a needed step-up for expanding human space activities, of both industrial and scientific nature. Such ambition has resulted in a renaissance of the nuclear sector for space applications, and particularly for energy production purposes, thanks to its intrinsic high energy density, reliability and durability attributes.

This increasing interest has prompted ENEA and the Italian Space Agency to engage in a first feasibility study regarding a Surface Nuclear Reactor (SNR) as a power source for a lunar outpost. The study has established ENEA’s role in the field as the glue between the Italian nuclear and space industrial and scientific communities.

ENEA’s role in the Italian landscape will be strengthened further by the recently started Lunar Energy Systems with Nuclear Energy (SELENE) project, funded again by the Italian Space Agency for a global worth of 2 million euros.

The Project key objective is the study of innovative technological solutions for the creation and management of an energy infrastructure called Moon Energy Hub (MEnH). The MEnH gravitates around the use of SNRs, a solution that promises to overcome the limits of traditional energy technologies, such as radio-isotope systems and solar panels. The latter, although used until now, have shown inefficiencies, poor scalability, short operational life and weakness (as per cosmic radiation).

The MEnH aims to provide a stable energy base to support a wide range of lunar activities, both human and robotic. The Hub will be designed to be an integrated, modular system, capable of expanding and adapting to the evolving needs of lunar missions. For this the MEnH includes energy storage systems as well as a steerable power transmission system, to support activities at a distance from the generation center, and a mobile reception system for less energy-intensive activities.

In SELENE many technological and scientific challenges, requiring innovations will be addressed in areas such as heat dissipation, energy conversion, sensors, high automation and wireless power transmission. A central element of the Project is experimental testing, a "proof of concept", of the envisaged solution for heat removal from the nuclear core: namely liquid metals heat pipes. This will allow validating the performance of the system and increasing its technological maturity.

SELENE will also tackle one of the main enabling conditions for bringing the MEnH to maturity: a regulatory framework and established safety approach for nuclear for space applications. Such a framework is currently lacking and in the project recommendations will be drafted for its construction based on the international work performed so far by IAEA and the experience with radio-isotopes generators and nuclear-power satellites.

In summary, MEnH represents an integrated approach for supporting lunar missions, combining technological innovation and a strategic vision to ensure operability, reliability and compactness in an extremely demanding environment such as the lunar one. With the aim of defining a clear operational scenario and drawing up a roadmap to achieve it, the SELENE project stands as a cornerstone for future space exploration.

To make the vision of the Project a reality over the 3 years of its duration, the SELENE consortium includes, in addition to ENEA as coordinator, also the transversal skills of the Energy Department of the Polytechnic of Milan and the industrial vision and spatial heritage brought by Thales Alenia Space Italia.