Real-world data from China's Chang'e 4 mission on the Moon's far side reveals that future astronauts could face about 200 times more radiation than on Earth, requiring robust shielding like 80 cm-thick regolith walls.
One of the greatest risks in long-duration space missions is exposure to cosmic radiation—high-energy particles streaming through interstellar space near light speed. Earth's magnetic field and atmosphere shield us from these threats, for which humans have not evolved natural defenses.
Without this protection, radiation can ionize atoms, damaging or breaking DNA molecules and killing cells. Acute effects include nausea, vomiting, and diarrhea, while chronic exposure raises risks of cataracts, cancer, and gastrointestinal damage, as shown in prior simulations.
To support sustainable lunar exploration, accurately measuring radiation levels is crucial. A Sino-German team analyzed data from China's Chang'e 4 lander on the Moon's far side, publishing their findings in Science Advances.
The study estimates a daily radiation dose on the Moon of about 1.3 millisieverts—roughly two to three times higher than what astronauts experience aboard the International Space Station.
As lead author Robert Wimmer-Schweingruber notes, this is “about 200 times higher than on Earth's surface and 5 to 10 times more than a New York-Frankfurt flight.” Unlike short flights, lunar missions expose crews to these levels for extended periods.
These measurements align closely with predictive models and should hold across most of the lunar surface, except near deep crater walls, where shielding from the sky reduces exposure. “The less sky you see, the better,” Wimmer-Schweingruber summarizes.
The team recommends habitats built from lunar regolith with walls at least 80 centimeters thick for adequate protection.
