Research team extracts cool water from moon dust

As part of an EU-funded project called LUWEX, experts from Germany, Poland, Austria and Italy worked together under the leadership of the German Aerospace Center (DLR) in Bremen and the Technical University (TU) Braunschweig. The goal was to show how water can be obtained from lunar regolith dust, which contains ice or to which ice adheres.

Think carefully about what goes in the moon suitcase
When you look in the direction of a moon base, which is repeatedly placed in hypothetical space by space agencies such as the European ESA or its American counterpart NASA, you have to think very carefully about what you take with you from Earth at a very specific moment. expensive price and what you win on the spot to keep it in circulation as long as possible, explains project partner Barbara Imhof from the Viennese space architecture platform Liquifer on the project website.

The expert and her partners think intensively about what can be used on the Earth satellite itself. For example, in 2023, a method of using concentrated sunlight to make paving stones from the lunar regolith was presented in the journal ‘Scientific Reports’.

But moon rocks or moon dust also contain water in the form of ice. How much of this is in places where future bases could be located is not clear. However, there are estimates that “up to ten percent of the water could be in the upper layers of the ground in the dark craters at the moon’s south pole,” according to DLR project manager Paul Zabel: “However, this still needs to be done .” confirmed by on-site investigation.”

Tests on “Komet” in Braunschweig, Germany
Nevertheless, the scientists took this as an opportunity to come up with technical solutions to extract the water from the dust. The approach was then investigated at the “Comet Physics Laboratory” (CoPhyLab) in Braunschweig. However, due to the lack of frozen moon dust, it had to be simulated first.

The team created a dust-ice mixture in extreme cold. A mixture was created containing spherical ice particles with an average radius of just 2.4 micrometers – equivalent to about one-twentieth the thickness of a hair, the team said in a press release.

The lunar water extraction system built by the German researchers was then brought into contact with the simulated moon dust in the CoPhyLab – a thermal vacuum chamber designed to mimic conditions on a comet down to minus 170 degrees Celsius. Up to 15 kilograms of ‘moon rock’ could be processed under conditions as close to the moon as possible.

In the system, the mixture was heated and stirred simultaneously. The ice then turned directly into water vapor, which then froze on the walls of extremely cold copper pipes. From there, the water can be collected again as ice, liquefied and purified.

The process needs to be further developed
This process seems promising, even though it is “already very energy intensive,” as Zabel admits. There are also some open questions about how to purify the water. On the one hand, it is difficult to remove any dust particles smaller than one micrometer from the liquid. “On the other hand, the moon rock has never come into contact with liquid water, so it is very likely that metals such as iron and aluminum or even methanol will dissolve from the dust and end up in the water. It is imperative that these contaminants are removed from the water,” says Zabel.

The approach has now “reached a certain level of technological maturity”. According to the DLR researcher, “further development steps are needed, which we want to tackle in the coming years,” until we are prepared for possible first tests on the lunar surface.

There is great potential for procedures
In any case, the potential is great: the water obtained in this way could be used outside Earth as drinking water, to produce oxygen or as a component of liquid rocket fuel – for the project partners “a decisive step in supporting sustainable research into solar system.”