Chang’e-4 lunar lander imaged by the mission’s Yutu-2 rover. Arrow points to the Germany-provided Lunar Lander Neutron and Dosimetry (LND) instrument.
Credit: CNSA/CLEP/NAOC

 

How intense and hazardous to humans is cosmic radiation on the Moon?

To be sure, any long-term stays on the Moon will expose astronauts’ bodies to high doses of radiation.

An instrument provided by Germany onboard China’s Chang’e-4 farside lander has measured space radiation in temporal resolution for the first time on the lunar farside.

Germany’s Lunar Lander Neutron and Dosimeter (LND) device.
Credit: Stefan Kolbe, CAU

First time measurements

China’s Chang’e-4 lunar lander touched down on the farside of the Moon on January 3, 2019. It carried the Lunar Lander Neutron and Dosimetry (LND) instrument. The device has made temporally resolved cosmic radiation measurements for the first time.

Results from the experiment have been published in the scientific journal Science Advances, the work of an international group of scientists involved with the LND, including researchers from the German Aerospace Center (Deutsches Zentrum fuer Luft- und Raumfahrt; DLR).

DLR radiation physicist Thomas Berger from the DLR Institute of Aerospace Medicine, who participated in the research paper publication explains: “The radiation exposure we measured is a good indication of the radiation inside a spacesuit. The measurements give us an equivalent dose rate – the biologically weighted radiation dose per unit of time – of around 60 microsieverts per hour,” he noted in a DLR press statement.

Radiation protection

On longer missions to the Moon, astronauts will have to protect themselves from cosmic radiation by covering their habitat with a thick layer of lunar rock, for example.

Using local resources on the Moon can help make future crewed missions more sustainable and affordable.
Credit: RegoLight, visualization: Liquifer Systems Group, 2018

“This could reduce the risk of cancer and other illnesses caused by long periods of time spent on the Moon,” adds Robert Wimmer-Schweingruber of the Christian-Albrecht University (CAU) in Kiel, whose team developed and built the LND instrument.

With the LND instrument it is possible to measure the various characteristics of the radiation field over time intervals of one, 10 or 60 minutes. This enables researchers to calculate the “equivalent dose,” which is important for estimating biological effects.

China’s Chang’e-4 lander as viewed by Yutu-2 rover.
Credit: CNSA/CLEP

The instrument and lander were designed to conduct their measurements for at least one year. That’s a target they both have already surpassed. The data from the LND and the lander are transmitted to Earth via the Queqiao (“Magpie Bridge”) relay satellite that is located above the farside of the Moon.

The research paper – First measurements of the radiation dose on the lunar surface — can be viewed at:

https://advances.sciencemag.org/content/6/39/eaaz1334

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