Space Radiation: Limits and Health Risks for Astronauts
The NASA Artemis II mission departed for the Moon on April 1, 2026, marking the first human journey toward the satellite since the Apollo 17 mission concluded in December 1972. Even as the mission represents a primary step toward the permanent colonization of the Moon, it faces a critical obstacle in the form of space radiation.
Space radiation consists of charged particles with very high energy that are ubiquitous throughout the cosmos. These particles originate from galactic and intergalactic space, as well as from the Sun’s own nuclear and electromagnetic activity. Astronauts must navigate the Van Allen belts, regions where the Earth’s magnetic field traps radiation. The inner belt is composed primarily of electrons, while the outer belt contains energetic electrons, protons, and heavier nuclei.
Biological impact and genetic risks
The interaction between these high-energy particles and the human body produces effects comparable to those seen in nuclear reactor accidents or atomic explosions. According to Alfonso Blázquez Castro, a professor in the Biology Department at the Universidad Autónoma de Madrid, this radiation causes severe alterations in cellular function.
The damage occurs at a molecular and genetic level. Radiation can cause breaks in the various molecules of a cell either directly, through its extreme energy, or indirectly, by dissipating that energy to generate high concentrations of highly reactive chemical species. These interactions with DNA increase the long-term risk of cancer and cause significant molecular instability.
Mitigation and protection strategies
Although the radiation doses received by astronauts during the original Apollo missions are considered manageable, the goal of permanent lunar colonization requires more robust protection. Researchers are currently investigating several methods to shield explorers from these hazards.
Technical solutions under consideration include the implementation of material barriers and the use of magnetic fields to deflect charged particles. Beyond physical shielding, experts are exploring pharmaceutical and nutritional strategies to enhance the biological resilience of the crew.
To address the challenge of long-term exposure on the lunar surface, the construction of underground bases is being proposed as a viable solution to reduce the amount of radiation reaching inhabitants.