Inventors on hunt for way to make clean water on moon

Inventors hope to crack how to create a reliable clean water supply on the moon – and it may involve a microwave oven from Tesco.

The goal to set up a crewed lunar base was launched many moons ago but has yet to come to fruition. With reliance on water supplies from Earth risky and expensive, one of the many challenges is how to extract and purify water from ice lying in craters at the lunar south pole.

Such a supply would not only provide a resource for drinking and growing crops, but the water could also be split into hydrogen, for use as rocket fuel, and oxygen for residents to breathe.

Now the UK Space Agency has announced that it is awarding £30,000 in seed funding, with expert support, to each of 10 UK teams who are vying to solve the problem.

Lolan Naicker of Naicker Scientific Ltd, one of the UK finalists of the Aqualunar Challenge, said throwing open the conundrum to the public allows people with very different approaches to problem-solving, and very different backgrounds, to put forward potential answers.

“It’s extremely difficult to actually come up with a viable solution,” he said.

Naicker added that the first part of his team’s plan is to microwave the dirty lunar ice. “I’m literally going to go out today, buy a microwave oven from Tesco across the road, and strip it down, take out the magnetron and then try to incorporate that into the first part of my process,” he said.

Naicker and his team members are working on a “SonoChem System” that will use powerful sound waves to generate millions of tiny bubbles in lunar water, within which high temperatures and pressures are produced. That, Naicker said, produces highly reactive substances known as free radicals that break down contaminants in the water.

But while the team have a core idea, there is much more to do.

“Remember, we need to get from this dirty ice to liquid water first. And we need to do this in an environment that’s -200C – it’s vacuum conditions,” he said.

The teams only have seven months to develop their ideas before a winner and two runners-up are chosen in spring 2025, with the selected trio to share a further £300,000 to continue work on their solutions. In addition, approximately £600,000 is being dedicated to rewarding solutions from Canadian-led teams.

Meganne Christian, a UK Space Agency reserve astronaut and chair of the Aqualunar Challenge judging panel, said it is early days for Nasa’s Artemis mission, supported by the European Space Agency and others, which aims to put humans back on the moon.

“So it’s the right moment to have innovators looking into how to purify water on the moon – and to be fair, we didn’t actually know that there was water on the moon until relatively recently,” she said.

Christian added that the Aqualunar Challenge – which is funded by the UK Space Agency’s International Bilateral Fund and managed by Challenge Works in collaboration with the Canadian Space Agency – has a hugely diverse range of finalists, with teams also considering how the technologies could be applied on Earth.

Naicker said his team has a number of plans. “We could build a slightly bigger system, put it on the back of a van and drive it out to a war-torn area,” he said. “We could develop smaller appliances for the developing world where access to clean water is really challenging.”

Christian added the idea is that the new technologies could be also used on other space missions where there is water ice.

“We know that there’s water ice on Mars, for example. So absolutely, these technologies could be adapted for use on Mars and other planetary bodies, wherever we decide to go in the future,” she said.

The nine other UK finalists in the Aqualunar Challenge include:

Nascent Semiconductor Ltd, which is developing a compact system called the Titania-Diamond Annular Reactor (TiDAR). This will break down contaminants in lunar soil using a titanium dioxide catalyst activated by LED-based UV light with diamond electrodes.

The British Interplanetary Society in London, which has come up with Ganymede’s Chalice – a device in which a curved mirror focuses the Sun’s rays on an air-locked crucible containing lunar ice. The components within the ice can then be boiled in turn, and stored.

Queen Mary University of London, whose team is creating AquaLunarPure: a reactor that heats lunar ice to leave behind solid material then heats it to more than 373C at 220 bars of pressure to turn it into “supercritical water”, whereby contaminants are removed by oxidation.

Minima Design Ltd, Suffolk, which has developed a Cyclic Volatile Extractor (CVE) – in which dirty ice is heated within a novel closed chamber under variable pressures, allowing different contaminants to be removed and stored.

RedSpace Ltd, which has come up with Frank, a Filtered Regolith Aqua Neutralisation Kit, in which lunar soil is heated to remove volatile gases before the remaining material is passed through a membrane to separate solid particles and liquid. The latter is then distilled to obtain water.

Perspective Space-Tech Ltd, which has created an innovative lunar water resource system called I-LUNASYS, in which lunar samples are heated to remove impurities as gas. Reverse osmosis is then used to separate water molecules from the sample, with the final step involving a UV filtration system.

Shaun Fletcher and Dr Lukman Yusuf from the University of Glasgow, who plan to melt dirty ice, remove large soil particles and then pump the water through an ultrasound system. This will remove gases, destroy pollutants and clump together any lunar dust, before the water is filtered to remove remaining contaminants.

Regolithix Ltd, who are developing a Regolith Ice Plasma Purifier for Lunar Exploration (RIPPLE), in which dirty lunar ice will be heated, with water vapour and solid particles separated by a device akin to a salad spinner. The vapour can then be split using a plasma torch, and the hydrogen and oxygen isolated using a molecular sieve.

Interstellar Mapping, which have come up with a Static Water Extraction System (SWES) to sublimate different volatile substances in the lunar soil at lower temperatures than ice and water are extracted and stored. The sample is then heated again to turn the water to steam which is extracted and cooled.