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First measurements of radiation levels on the moon

Date:
September 26, 2020
Source:
Kiel University
Summary:
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. Scientists report for the first time on time-resolved measurements of the radiation on the moon. 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.
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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 (25 September) of the 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.

The measurements were taken on board the Chinese lunar lander Chang'e-4, which landed on the far side of the moon on 3 January 2019. The device from Kiel takes measurements during the lunar "daylight," and like all other scientific equipment, switches off during the very cold and nearly two-week-long lunar night, to conserve battery power. The device and lander were scheduled to take measurements for at least a year, and have now already exceeded this goal. The data from the device and the lander is transmitted back to earth via the relay satellite Queqiao, which is located behind the moon.

The data obtained also has some relevance with respect to future interplanetary missions. Since the moon has neither a protective magnetic field nor an atmosphere, the radiation field on the surface of the moon is similar to that in interplanetary space, apart from the shielding by the moon itself. "This is why the measurements taken by the LND will also be used to review and further develop models that can be used for future missions. For example, if a manned mission departs to Mars, the new findings enable us to reliably estimate the anticipated radiation exposure in advance. That's why it is important that our detector also allows us to measure the composition of the radiation," said Wimmer-Schweingruber.


Story Source:

Materials provided by Kiel University. Note: Content may be edited for style and length.


Journal Reference:

  1. Shenyi Zhang, Robert F. Wimmer-Schweingruber, Jia Yu, Chi Wang, Qiang Fu, Yongliao Zou, Yueqiang Sun, Chunqin Wang, Donghui Hou, Stephan I. Böttcher, Sönke Burmeister, Lars Seimetz, Björn Schuster, Violetta Knierim, Guohong Shen, Bin Yuan, Henning Lohf, Jingnan Guo, Zigong Xu, Johan L. Freiherr von Forstner, Shrinivasrao R. Kulkarni, Haitao Xu, Changbin Xue, Jun Li, Zhe Zhang, He Zhang, Thomas Berger, Daniel Matthiä, Christine E. Hellweg, Xufeng Hou, Jinbin Cao, Zhen Chang, Binquan Zhang, Yuesong Chen, Hao Geng, Zida Quan. First measurements of the radiation dose on the lunar surface. Science Advances, 2020; 6 (39): eaaz1334 DOI: 10.1126/sciadv.aaz1334

Cite This Page:

Kiel University. "First measurements of radiation levels on the moon." ScienceDaily. ScienceDaily, 26 September 2020. <www.sciencedaily.com/releases/2020/09/200926145212.htm>.
Kiel University. (2020, September 26). First measurements of radiation levels on the moon. ScienceDaily. Retrieved June 24, 2024 from www.sciencedaily.com/releases/2020/09/200926145212.htm
Kiel University. "First measurements of radiation levels on the moon." ScienceDaily. www.sciencedaily.com/releases/2020/09/200926145212.htm (accessed June 24, 2024).

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