Finally we know what kind of radiation environment the next moonwalkers are coming from.
Astronauts jumping over the moon soak about 60 microsievers of radiation per hour, a new study report. That is 5 to 10 times higher than the rate experienced on a trans-Atlantic passenger flight and nearly 200 times that we get over the Earth, study team members said.
In other words, a long-term stay at the moon the bodies of astronauts will be exposed to high doses of radiation, “co-author Thomas Berger, a radiation physicist at the German Aerospace Center’s Institute of Aerospace Medicine in Cologne, said in a statement.
Those numbers are really high ̵1; but they are probably not high enough to hinder personnel from exploring the moon, as we will see.
Related: The hint of space radiation to astronauts is explained (infographic)
A result of pioneering from a pioneering lander
Scientists have long known that the radiation level is relatively high on the moon, with no thick atmosphere or a magnetic field to protect it. (Our Earth, fortunately, possesses the same kind of shield.) But accurate numbers have proven to be elusive.
For example, NASA’s dosimeter Apollo astronauts taken in the moon from 1969 to 1972 recorded combined, total-mission exposure, not a detailed breakdown of radiation levels over the moon. The new study gives us detailed breakdown.
The figures are courtesy of the Lunar Lander Neutron and Dosimetry instrument (LND), an experiment developed by the German aboard China Chang’e 4 month mission. The history of Chang’e 4 was made in January 2019 by performing the first soft touch on a large part of the moon that was not observed.
Chang’e 4 consists of a the rover named Yutu-2 (“Jade Rabbit 2”) and a lander, both of which will still be strong. LND is part of the lander’s scientific freight, and this slightly contested position provides “a good indication of radiation within a spacesuit,” Berger said.
Charging particles such as galactic cosmic ray (GCRs), accelerated by the massive speed of distant supernova explosions, contribute nearly 75% to the total lunar-surface dose rate of 60 microsieverts per hour, LND data indicate.
The GCR exposure rate on the moon is therefore about 2.6 times higher than that experienced by astronauts aboard the International Space Station, according to the new study, published online Friday (September 25) in the journal Science Advances. (The space station, while orbiting above most of Earth’s atmosphere, receives protection from our planet’s magnetic field.)
Related: China released a large group of Chang’e 4 images from the far side of the moon
There is no roadblock for Artemis
NASA is working on astronauts will land on the moon in 2024 and establish a sustainable human presence in and around the Earth’s closest neighbors by the end of the decade, by a program called Artemis. The lessons learned during Artemis will also help pave the way for crewed leap to Mars, which NASA aims to achieve by 2030, agency officials said.
Newly reported numbers will not lose any of Artemis’ grand plans, a reading of NASA radiation exposure rules suggests Those rules stipulate that no astronaut will receive a career in radiation dose that increases the risk of cancer death by more than 3%. The total equivalent dose that poses this risk depends on the sex and age of the astronaut at the onset of radiation exposure, among other factors.
Women and spaceflyer starting children are at greater risk. For example
But at 60 microsieverts per hour, the 25-year-old female astronaut can spend a total of nearly 700 days on Earth exploring the moon’s surface before violating her life exposure limit (although this calculation does not considering his travel time to and from the moon).
And the GCR numbers measured by LND are likely to be on high for any exposure that moonwalkers will experience, the study authors said. That is because the data is collected during an inactive stretch 11-year cycle of day activity, with relatively few GCRs zooming in on the heliosphere, the bubble of charged particles and the magnetic field that the sun blows around it.
All of this does not mean that Artemis astronauts will send the moon within a two-year stint, however; No doubt NASA will want to stretch the radiation exposure of spaceflyers over time for the sake of safety. Astronaut agencies that fly aboard space stations, for example, cannot exceed 50,000 microsieverts of exposure per year.
And NASA is likely to suffer even more to reduce the radiation risk experienced by Artemis astronauts, especially those who spend a large chunk of time in and around the moon.
“On longer lunar missions, astronauts need to protect themselves from it [radiation exposure] – by covering their habitat with a thick layer of lunar rock, for example, “co-author Robert Wimmer-Schweingruber, of Christian-Albrecht University in Kiel, Germany, said in a statement.
“It can reduce the risk of cancer and other diseases caused by the long time spent in the moon,” said Wimmer-Schweingruber, whose team founded LND.
Such measures will also help guard against the sporadic but potentially dangerous sunrise known as solar particle events (SPEs). LND does not get any SPEs during the reach covered by the new study, but subsequent lunar explorers may be hit by one.
Mike Wall is the author of “Out There” (Grand Central Publishing, 2018; illustrated by Karl Tate), a book about the search for alien life. Follow him on Twitter @michaeldwall. Follow us on Twitter @Spacedotcom or Facebook.