CNES projects library

December 10, 2023

Chang'e 6/DORN

There are many processes on the surface of the Moon that we have yet to fathom. But after years studying our natural satellite from orbit, we are now poised to acquire in-situ data. The DORN instrument is all set to depart for the Moon riding on China’s Chang’e 6 lander to investigate radon, a radioactive gas continuously emanating from lunar soil.

In the spring of 2019, the presidents of CNSA (China National Space Administration) and CNES (Centre National d’Etudes Spatiales) signed a memorandum of understanding to fly a French payload on the Chang’e 6 lunar mission. DORN was selected by CNES in September of the same year, becoming the first French-Chinese collaboration in the field of planetary exploration, officialized on 6 November 2019 during President Emmanuel Macron’s state visit to China.

The DORN demonstrator, the first French scientific instrument built to operate on the Moon’s surface, is designed to measure radon, a radioactive gas continuously emanating from lunar regolith due to the decay of uranium.

It will measure radon concentration on the Moon’s surface for the first time ever to probe the origins of the tenuous “atmosphere” that planetary scientists call the lunar exosphere. To this end, DORN will investigate outgassing of radon and its transport in the lunar environment.

DORN will also refine measurements of uranium previously acquired from lunar orbit and yield new insights into the transport of lunar dust, as well as the migration of water molecules to polar craters where they form ice.

The French instrument riding aboard China’s Chang’e-6 spacecraft will operate in the South Pole-Aitken basin, an area spanning 2,500 kilometres where no samples have ever been collected before. This is the largest and deepest impact crater on the Moon, and at 10 kilometres deep the region where elevations are lowest and among the locations where the lunar crust is thinnest.

Key figures

  • 4,5 kg : masse de l'instrument DORN
  • 48h : durée de l'expérience à la surface de la Lune
  • 2 kg: quantity of samples to be returned to Earth
  • 40 cm²: Alpha particle detection surface on DORN


cnes's role in the project

DORN was designed and built at the IRAP astrophysics and planetology research institute with oversight from CNES. The agency is supporting all of the French research laboratories contributing to the mission.