A team of researchers from Hunan University, the China Academy of Building Research, the Deep Space Exploration Laboratory in Hefei and the University of Science and Technology of China has proposed a fundamentally new strategy for building lunar bases. In a paper published in npj Space Exploration, the researchers presented an “evolutionary” concept for supplying thermal energy to moonbases. This concept envisages the step-by-step development of an energy infrastructure that will evolve alongside the lunar base, from survival in an extreme environment to sustainable industrial activity.
The biggest challenge of lunar exploration is lunar nights lasting approximately 14 Earth days. During this period, the surface temperature drops to about minus 170 degrees Celsius, with no solar energy and nonexistent atmosphere, which means that heat freely escapes into space. In the course of previous missions, targeted solutions were used for unmanned spacecraft, including multilayer thermal insulation and radioisotope heaters. However, these solutions are insufficient for a permanent base with a crew, research laboratories and production modules. The researchers propose that the energy system be viewed as a scalable architecture capable of increasing complexity and capacity.
Their roadmap includes three stages. During the first stage, which is to be implemented before 2030, radioisotope thermoelectric generators will be the primary heat source. This is the most mature technology that has already proven its reliability in space missions. One such module, which has a power output of some 110 W, weighs about 45 kg, and the cost of developing these systems is estimated at approximately $100 million. These systems can generate hundreds of watts or a few kilowatts of power. This is sufficient for the first unmanned stations and small rovers that need to survive the lunar night with minimal power consumption.
The second stage, which is slated for 2030–2035, involves the creation of a permanently inhabited lunar base. Here, the use of local resources becomes key. The researchers propose using lunar soil (regolith) as a heat accumulator. In the daytime, regolith is heated via solar concentrators, whereas at night the accumulated heat is used for heating and power generation. Since the thermal conductivity of regolith is very low, the scientists analyzed the methods for its modification: compaction, sintering, addition of impurities and laser melting. In its basic configuration, the regolith-based storage system can generate some 6–10 kW of electricity with a system weighing about 1 ton. Calculations and laboratory experiments show that the material’s thermal conductivity could increase tenfold after being treated in this manner. This will considerably reduce the base’s dependence on fuel and equipment supplies from Earth.
As indicated in the study, the third stage will kick off after 2035, with the base transitioning to long-term occupancy and industrial activity. At that point, the thermal load could reach hundreds of kilowatts or even megawatts. It is proposed to use nuclear fission reactors with a thermal output ranging from tens to over 100 kW with the potential to reach megawatt levels as the basis. For instance, land-based reactor designs with a power output of about 50 kW weigh approximately 9 tons. However, the researchers do not rule out existing technologies. The proposed concept envisages an integrated network of multiple sources: the reactor provides the base load, solar concentrators and regolith storage units smooth out consumption peaks, and radioisotope generators serve as backup sources for critical life support systems.
The next step in the study is expected to include ground-based thermal vacuum testing, fine-tuning of materials in conditions as close as possible to the lunar environment and small-scale demonstration experiments on the Moon.
