We finally know what kind of radiation environment future moonwalkers will enter.
Astronauts jumping on the lunar surface will absorb about 60 microsieverts of radiation per hour, according to a new study. That’s 5 to 10 times higher than the percentage observed on a transatlantic passenger flight, and about 200 times more than what we get on Earth’s surface, said members of the research team.
“In other words, a long stay The moon will expose the bodies of astronauts to high doses of radiation “, co-authored by Thomas Berger, a radiation physicist at the Institute of Aerospace Medicine in Cologne at the German Aerospace Center, said in a statement.
These numbers are indeed high ̵
Connected: Cosmic radiation threat to astronauts explained (infographic)
Pioneering result of a pioneer landing
Scientists have long known that radiation levels are relatively high on the moon, which does not have a dense atmosphere or a magnetic field to protect it. (Fortunately, our Earth has both types of shields.) But the exact numbers turned out to be elusive.
For example, NASA dosimeters Astronauts of Apollo taken to the moon from 1969 to 1972 recorded the cumulative total exposure rather than a detailed breakdown of radiation levels on the lunar surface. The new study gives us this detailed breakdown.
The figures are courtesy of the Lunar Lander (LND) neutron and dosimetry instrument, a German experiment based on Chinese Chang’e 4 moon mission. Chang’e 4 went down in history in January 2019, performing the first soft touchdown of its kind on the largely unexplored distant side of the moon.
Chang’e 4 consists of a a rover named Yutu-2 (“Jade Rabbit 2”) and a downhill, both still strong. The LND is part of the scientific payload of the lander, and its partially shielded position provides “a good indication of radiation in the spacesuit,” Berger said.
Charged particles such as galactic cosmic rays (GCR), which accelerates to huge speeds from distant supernova explosions, contribute about 75% to the total lunar surface dose of 60 microsieverts per hour, LND data show.
Therefore, the GCR’s exposure to the moon is about 2.6 times higher than that of astronauts aboard the International Space Station, according to the new study, which was published online Friday (September 25th) in the journal Science Advances. (The space station, while orbiting most of the Earth’s atmosphere, receives protection from our planet’s magnetic field.)
Connected: China is releasing a huge batch of images from Chang’e 4 on the far side of the moon
There is no obstacle for Artemis
NASA works for astronauts on the land of the moon in 2024 and establishing a sustainable human presence in and around Earth’s nearest neighbor by the end of the decade through a a program called Artemis. Lessons learned during Artemis will also help pave the way for the crew to jump to Mars, which NASA aims to achieve in the 2030s, agency officials said.
The new announced numbers will not thwart any big plans of Artemis, reading on NASA rules on radiation exposure suggests. These rules stipulate that no astronaut receives a career radiation dose that increases the risk of lifelong cancer mortality by more than 3%. The total equivalent dose that this risk poses depends on the gender and age of the astronaut at the start of the exposure, among other factors.
Women and space pilots who start young are at greater risk. For example, a female astronaut who begins her career in space flight at the tender age of 25 has a career exposure limit of 1 million microsieverts, while the cap is four times larger than that of a man who begins flying at 55- years old.
But at 60 microsieverts per hour, this 25-year-old female astronaut could spend a total of nearly 700 Earth days exploring the lunar surface before violating her lifetime limit (although this calculation does not take into account her time in and out of the moon). .
And the GCR numbers measured by the LND are probably the highest for any exposure lunatics will receive, the study’s authors said. This is because the data was collected during an inactive section of the solar 11-year cycle of activitywhen relatively more GCRs were able to enlarge the heliosphere, the bubble of charged particles and magnetic fields that the sun blows around itself.
However, all this does not mean that Artemis’ astronauts will send the ship to the moon in two years; NASA will no doubt want to extend the radiation exposure of spacecraft over time for safety reasons. Astronaut agencies that fly aboard the space station, for example, cannot exceed 50,000 microsieverts per exposure.
And NASA is likely to continue its efforts to minimize the radiation risk experienced by Artemis astronauts, especially those who spend much of their time on and around the moon.
“On longer missions to the moon, astronauts will have to protect themselves from it [radiation exposure] – by covering their habitat with a thick layer of lunar rock, for example, “said study co-author Robert Wiemer-Schweingruber of Christian-Albrecht University in Kiel, Germany.
“This can reduce the risk of cancer and other diseases caused by long periods of time on the moon,” said Wiemer-Schweingruber, whose team built LND.
Such measures would also help prevent sporadic but potentially dangerous solar flares, known as solar particle events (SPE). The LND did not take any SPEs during the area covered by the new study, but future lunar explorers could be hit by one.
Mike Wall is the author of “There” (Grand Central Publishing, 2018; illustrated by Carl Tate), a book about the search for extraterrestrial life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.