Lunar Lander Neutron and Dosimetry: First Measurements of Radiation Levels on the Moon
The Chang’e-4 lunar probe, photographed from the Yutu-2 rover. The measuring device from Kiel is located on the left behind the antenna.
In the coming years and decades, various nations want to explore the moon, and plan to send astronauts there again for this purpose. But on our inhospitable satellite, space radiation poses a significant risk. The Apollo astronauts carried so-called dosimeters with them, which performed rudimentary measurements of the total radiation exposure during their entire expedition to the moon and back again. In the current issue (September 25, 2020) of the prestigious journal Science Advances, Chinese and German scientists report for the first time on time-resolved measurements of the radiation on the moon.
The “Lunar Lander Neutron and Dosimetry” (LND) was developed and built at Kiel University, on behalf of the Space Administration at the German Aerospace Center (DLR), with funding from the Federal Ministry for Economic Affairs and Energy (BMWi). The measurements taken by the LND allow the calculation of the so-called equivalent dose. This is important to estimate the biological effects of space radiation on humans. “The radiation exposure we have measured is a good benchmark for the radiation within an astronaut suit,” said Thomas Berger of the German Aerospace Center in Cologne, co-author of the publication.
The measurements show an equivalent dose rate of about 60 microsieverts per hour. In comparison, on a long-haul flight from Frankfurt to New York, it is about 5 to 10 times lower, and on the ground well over 200 times lower. Since astronauts would be on the moon for much longer than passengers flying to New York and back, this represents considerable exposure for humans, said Robert Wimmer-Schweingruber from Kiel University, whose team developed and built the instrument. “We humans are not really made to withstand space radiation. However, astronauts can and should shield themselves as far as possible during longer stays on the moon, for example by covering their habitat with a thick layer of lunar soil,” explained second author Wimmer-Schweingruber. “During long-term stays on the moon, the astronauts’ risk of getting cancer and other diseases could thus be reduced,” added co-author Christine Hellweg from the German Aerospace Center.