Radon emissions on Mars and the Moon: the contribution of meteorites

 An international team of researchers, including members of 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 radon emissions from Martian and lunar meteorites. The study, published on 28 January in the journal Scientific Reports, aims to improve our understanding of the surface and atmospheric processes of Mars and the Moon, while preparing for future missions to measure radioactivity in situ.

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

The team analysed fifteen Martian and lunar meteorites in the laboratory and calculated their radon emissions. The results show that these meteorites release less radon than most terrestrial rocks, but at levels comparable to primitive basalts (ancient volcanic rocks). After correcting for the effects of temperature 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 of Mars (78 to 280 atoms per m² per second) and the Moon (160 to 210 atoms per m² per second), which are much lower than those of the Earth (10,000 atoms per m² per second). These differences suggest that the radon flux mainly depends on several factors: temperature, amount of water, chemical composition, internal structure and tectonic activity of the planet.

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

Référence : 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,