New Measurements on the Moon Show Harmful Radiation Levels

    04 October 2020

    New measurements show that radiation levels on the moon are two to three times higher than on the International Space Station.

    The measurements were taken by an instrument on China's Chang'e-4 lunar lander. The spacecraft touched down on the far side of the moon in January of 2019.

    German and Chinese scientists involved in the experiment say the Chinese lander provided the first "active" measurements of radiation levels on the surface of the moon. The findings were recently reported in a study in the publication Science Advances.

    The full moon shines surrounded by clouds in the outskirts of Frankfurt, Germany, early Wednesday, Sept. 2, 2020.
    The full moon shines surrounded by clouds in the outskirts of Frankfurt, Germany, early Wednesday, Sept. 2, 2020.

    The study comes as the United States and several other countries develop plans to send astronauts to explore the moon. The American space agency NASA has a goal of landing the first woman and next man on the moon by 2024 as part of its Artemis program. It also wants to set up a long-term base on the moon by 2028.

    But space radiation presents major health risks to future astronauts. Cancer is the main health concern, but radiation exposure can also lead to other diseases.

    NASA has already warned that space travelers spending long periods in places like the moon or Mars will face high levels of harmful radiation.

    Earth's atmosphere and magnetic shield protect humans from the extreme radiation present in the universe. But astronauts aboard the International Space Station receive more than 10 times the radiation that we receive on Earth.

    The new study suggests that radiation exposure on the moon would be 2.6 higher than on the International Space Station. The researchers said astronauts on the moon would get about 200 times more radiation than we experience on Earth.

    Robert Wimmer-Schweingruber is an astrophysicist at the University of Kiel in Germany. He helped lead the research. He told the French press agency, AFP, the finding led his team to predict that astronauts would only be able to stay on the moon for about two months under current conditions.

    "Humans are not really made for these radiation levels and should protect themselves when on the moon," Wimmer-Schweingruber said.

    He added that radiation levels should be about the same in all areas of the moon, except for near the walls of deep craters. "Basically, the less you see of the sky, the better," he said.

    The researchers suggested that astronauts could build shelters made of moon dirt for protection during stays of more than a few days. They said the shelters' walls would need to be about least 80 centimeters thick. A wall thicker than that, they said, could cause the dirt to give off its own secondary radiation. Such radiation is created when cosmic rays interact with the lunar soil.

    NASA has said it will have radiation detectors and a safe shelter on all of its crew spacecraft flying to the moon.

    Thomas Berger is a physicist with the German Space Agency's medicine institute. He also took part in the study. He called results of the experiment "immense." The method finally gives scientists a "data set" that can be used to effectively measure radiation and study its effects on humans, Berger said.

    The radiation levels described in the study are similar to levels that models have already predicted. Kerry Lee is a space radiation expert at NASA's Johnson Space Center in Houston. Lee said the measurements "agree nearly exactly" with those made by a detector on a NASA orbiter that has been circling the moon for more than 10 years.

    "It is nice to see confirmation of what we think, and that our understanding of how radiation interacts with the moon, is as expected," Lee said.

    I'm Bryan Lynn.

    Bryan Lynn wrote this story for VOA Learning English, based on reports from The Associated Press, Agence France-Presse, Science Advances and Kiel University. Ashley Thompson was the editor.

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    Words in This Story

    exposuren. coming in contact with something

    shieldn. an object used to protect something

    cratern. a large round hole in the ground made by the explosion of a bomb or by something falling from the sky

    cosmic ray – n. high-energy particles that move through space at nearly the speed of light

    detector n. a device that helps notice something that is hidden or unclear

    immense adj. extremely good

    interact – v. to communicate with or react to

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