What do these radioactive emissions from lunar and Martian meteorites tell us? ☢️

An international team of researchers, including members from the Institut de physique du globe de Paris (IPGP, Université Paris Cité, CNRS) and the Natural History Museum of Vienna (NHMW) in Austria, has studied the emission of radon from Martian and lunar meteorites. This study, published in the journal Scientific Reports on January 28, aims to better understand the processes on the surface and in the atmosphere of Mars and the Moon, while preparing for future missions to measure radioactivity in situ.


Unlike other gases used to analyze planets, radon is produced directly in rocks by the decay of radium. Its study therefore allows the detection of certain physical phenomena, particularly those involving water. However, the limited number of samples brought back from these planets makes it difficult to accurately estimate these emissions.

The team analyzed fifteen Martian and lunar meteorites in the laboratory and was thus able to calculate their radon emissions. The results show that these meteorites release less radon than most terrestrial rocks, but in quantities comparable to primitive basalts (deep-origin volcanic rocks). After correcting for temperature effects and terrestrial alteration, the radon emission is low, around 5 to 8%.



Thanks to these measurements, the researchers were able to estimate the radon emissions from Mars (78 to 280 atoms per m² per second) and the Moon (160 to 210 atoms per m² per second), significantly lower than those of Earth (10,000 atoms per m² per second). These differences suggest that the radon flux depends mainly on several factors: temperature, amount of water, chemical composition, internal structure, and tectonic activity of the planet.

This study provides a reference basis for radioactivity measurements to be carried out by the Franco-Chinese mission DORN/Chang'E 6 in June 2024 and for future space explorations.

Reference:
Girault, F., Ferrière, L., Sadaka, C., Chacartegui Rojo, Í.L., Losno, R., Moynier, F., Perrier, F., Meslin, P.-Y. (2025).
Radon on Mars and the Moon derived from Martian and lunar meteorites.
Scientific Reports, 15, 3517, https://doi.org/10.1038/s41598-025-86842-x.