Moon safe for long-term human exploration, first surface radiation measurements show

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https://www.sciencemag.org/news/2020/09/moon-safe-long-term-human-exploration-first-surface-radiation-measurements-show

Source: By Adam Mann, Science Magazine. 

Excerpt: ...China’s Chang’e 4 lander has made the first detailed measurements of the intense radiation that blasts the lunar surface and found that it’s safe for human exploration. ...The robotic Chang’e 4 made history last year when it touched down in Von Kármán crater on the Moon’s far side, bringing a suite of instruments along for the ride. One of these was a new dosimeter.... The device measured hourly radiation rates and found that astronauts would be exposed to roughly 200 times the radiation levels as people on Earth, they report today in Science Advances. The dosimeter’s placement inside the Chang’e 4 probe provides partial shielding, much as an astronaut’s spacesuit would to their body, so the findings are quite applicable to human explorers, Wimmer-Schweingruber says. The measured dose is about five to 10 times what passengers on an intercontinental flight from New York City to Frankfurt, Germany, receive when the plane is above parts of the protective atmosphere, Wimmer-Schweingruber says. ...NASA is legally prohibited from increasing the risk of its astronauts dying from cancer by more than 3%, and these levels remain below that. What’s more, the researchers calculated that Moon bases covered with at least 50 centimeters of lunar soil would be sufficient to protect them. A deeper chamber shielded with about 10 meters of water would be enough to protect against occasional solar storms, which can cause radiation levels to spike dramatically. (Between the Apollo 16 and 17 missions, the Sun flared up in a way that could have caused radiation sickness, vomiting, and possibly death had astronauts been unprotected in space at the time.) Such a chamber would need to be reachable within 30 minutes, the amount of advanced warning time that is now possible with monitoring satellites.... 

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