A study published in Nature Astronomy identified regions of the south pole of the Moon where water has remained frozen for at least 1.5 billion years. These areas, known as “cold traps”, are located in deep craters that never receive direct sunlight and where temperatures drop below -160 °C, conditions that allow for the preservation of ice throughout the Moon’s geological history.
The science behind the discovery
The work was led by Oded Aharonson from the Weizmann Institute of Science (Israel), along with an international team. Using thermal models and orbital data from the Lunar Reconnaissance Orbiter (LRO), the researchers reconstructed the evolution of these regions and concluded that some have accumulated ice continuously for billions of years.
The low axial tilt of the Moon creates areas in permanent shadow, where thermal conditions are stable. However, the study reveals that billions of years ago, the tilt was greater, implying different solar exposure. Over time, the axis stabilized and increased the number of craters in perpetual darkness, transforming them into natural deposits of frozen water.
Implications for space exploration
The finding has a direct impact on NASA’s Artemis program, which seeks to establish a sustained presence on the Moon over the next decade. Lunar ice would not only be a source of drinking water for future crews but also a strategic energy resource: through electrolysis, it can be broken down into hydrogen and oxygen, essential components for producing rocket fuel.
This opens up the possibility of turning the lunar south pole into a refueling platform for more ambitious missions, such as manned trips to Mars.
New exploration strategies
The study also redefines exploration priorities. Some craters traditionally considered strategic may not be the most efficient for accumulating water, while other less explored regions show more stable conditions.
This new map serves as a guide for future robotic and manned missions, which will seek to obtain direct samples of lunar ice.
A limited resource
Scientists warn that lunar ice is not a renewable resource. Unlike Earth, where there is an active hydrological cycle, on the Moon, water accumulates through sporadic processes, such as comet impacts or interactions with the solar wind.
Once extracted and used, it is lost in the vacuum of space. Therefore, its exploitation poses technological, political, and environmental challenges, in a context where there are still no global agreements on the management of extraterrestrial resources.
The discovery of cold traps redefines the lunar exploration strategy and reinforces the interest in establishing permanent bases outside of Earth. The ice of the lunar south pole could become the resource that makes the difference between temporary missions and a true sustained human presence in space.
