Scientists have made a significant breakthrough in understanding where water on the Moon may be hiding. A recent analysis of Moon dust collected by China’s Chang’e-5 lander has revealed that a mineral within the dust contains an astonishing amount of water—so much so that water constitutes 41 percent of its weight. This mineral is similar to novograblenovite, a rare substance first identified in basaltic rock from Russia’s Kamchatka Peninsula only a few years ago. Both the lunar and terrestrial minerals share the chemical formula (NH4)MgCl3·6H2O and have comparable crystalline structures.

The discovery of this water-rich mineral on the Moon is not only intriguing for what it tells us about lunar water but also for the clues it may provide about the Moon’s geological history and the origins of its water. The fact that we can study a similar mineral on Earth allows scientists to draw parallels and hypothesize about how water became trapped in the Moon’s surface materials.

Unraveling the Mystery of Lunar Water

The origin, presence, and distribution of water on the Moon have long puzzled scientists. Understanding where this moisture came from and where it is now is crucial for piecing together the history of the Earth-Moon system. Furthermore, identifying water sources on the Moon is vital for future lunar exploration, as water is essential for human survival.

In past lunar missions, water has been detected in older samples, often trapped in tiny glass beads formed when surface material melts into spherules. Additionally, water signals have been detected in the spectrum of light reflected from the Moon’s surface, suggesting that there could be more water than previously thought.

One prevailing theory is that water on the Moon is bound up in minerals within the lunar regolith, the layer of loose, fragmented material covering solid rock. However, previous studies have hinted that the hydrogen and oxygen in Moon dirt might be part of other hydroxyl molecules—compounds similar to water but with different proportions of hydrogen and oxygen.

When the Chang’e-5 lander touched down on the Moon in December 2020, it made a groundbreaking discovery—the first in situ detection of what seemed to be water within a boulder on the Moon. However, it wasn’t clear whether this detection was actually molecular water or another hydroxyl molecule, necessitating further analysis.

Confirming Lunar Water Through Advanced Analysis

Led by physicists Shifeng Jin and Munan Hao of the Chinese Academy of Sciences, researchers conducted a thorough analysis of the samples returned to Earth by Chang’e-5. Using techniques such as X-ray crystal diffraction and chemical isotope analysis, they confirmed the presence of molecular water within the lunar regolith. Specifically, the mineral (NH4)MgCl3·6H2O was found to contain up to six water molecules.

Novograblenovite, the Earthly counterpart to this lunar mineral, forms under specific conditions, typically when hot basalt interacts with volcanic gases rich in water and ammonia. Although the lunar version of the mineral differs slightly—particularly in the composition of its chlorine isotopes—it likely formed through a similar process.

This discovery suggests that both water and ammonia were present on the Moon during periods of volcanic activity in its distant past. According to a statement from the Chinese Academy of Sciences, “Thermodynamic analysis shows that the lower limit of the water content in the lunar volcanic gas at that time was comparable to that of the driest volcano on Earth today, Lengai Volcano.”

Implications for Lunar Exploration and Beyond

The discovery of hydrated salts as a new source of water on the Moon is particularly significant. Unlike water ice, which is mostly found in shadowed craters at the lunar poles, these hydrated salts are more stable and could exist even in sunlit areas of the Moon. This stability means that future lunar missions may not have to rely solely on polar ice for water, opening up new possibilities for sustainable exploration and habitation.

Ultimately, this breakthrough reveals a more complex history of lunar volcanic activity and water retention, providing valuable insights into the evolution of the Moon and laying the groundwork for future exploration.

By Impact Lab