Vyacheslav Shurshakov, who leads the radiation safety division for manned space flights at the Institute of Biomedical Problems of the Russian Academy of Sciences, explains a clear limit: a person cannot live on a Moon base for more than two years. This assessment came during a talk at the Science Cafe, supported by the Andrey Melnichenko Foundation, where experts discussed the challenges of long-term life in space and how the Moon’s environment changes those limits. (Source: Institute of Biomedical Problems, Russian Academy of Sciences)
Shurshakov notes that over an astronaut’s entire career, the average exposure to cosmic radiation mirrors the exposure limits set for workers in nuclear industries or X-ray facilities. The lifetime dose benchmark he cites is about one thousand millisieverts. When translated into practical terms for extended missions, this means an astronaut could accumulate the permissible radiation dose within roughly four years aboard the space station. On a lunar surface mission, with the Moon’s harsher radiation conditions, the same person would hit that limit much sooner, within about two years under a conservative exposure model. These figures underscore a fundamental constraint on long-term human habitation beyond Earth. (Source: Institute of Biomedical Problems, Russian Academy of Sciences)
While the radiation barrier makes full-scale Moon colonization problematic, Shurshakov emphasizes that protection is possible with thoughtful design and shielding strategies. The Earth itself acts as a giant shield through its atmosphere and magnetic field, a natural defense that is not available to spacecraft or lunar habitats on the Moon. If mission planners can replicate protective environments, life support and habitat design can reduce radiation risks to levels compatible with sustained presence. This is a key area of ongoing research, blending material science, orbital dynamics, and habitat engineering to extend survivable time on the lunar surface. (Source: Institute of Biomedical Problems, Russian Academy of Sciences)
One of the core ideas proposed involves using abundant water as a shielding medium. Shurshakov explains that a water column equivalent to about ten meters could offer substantial protection against neutron flux, a major component of cosmic radiation. While it is impractical to build a ship with such a vertical barrier, the Moon reveals another possibility: locating a base in regions where regolith can be enriched with water or where water-rich ice deposits are accessible. In these settings, lunar regolith combined with water could form an effective shield, significantly mitigating radiation exposure for inhabitants. Water’s proven способность to slow down neutrons makes it a practical, reusable shield option for future lunar habitats. This approach could support longer missions and eventual sustained presence on the Moon while keeping crew doses within acceptable ranges. (Source: Institute of Biomedical Problems, Russian Academy of Sciences)