Why a Tesco microwave could play a key role in human life on the Moon

Without a reliable supply of water, human habitation on the Moon or Mars will always a remain a sci-fi dream. The developers of a new prize-winning prototype hope to start making it a reality – and are using some unexpected components to do so.

Designed to extract water from lunar soil, the SonoChem System from Gloucestershire engineer Lolan Naicker won the UK Space Agency’s Aqualunar Challenge in London last night (27 March).

Judging panel chair and reserve European Space Agency astronaut Meganne Christian said: “5.6% of the soil (known as regolith) around the Moon’s South Pole is estimated to be water frozen as ice. If it can be successfully extracted, separated from the soil and purified, it makes a crewed base viable.”

The ‘lunar regolith processing system’ from Naicker Scientific is designed to use microwaves to defrost the ice and then ultrasound to break down contaminants.

“Imagine digging up the soil in your back garden in the middle of winter and trying to extract frozen water to drink. Now imagine doing it in an environment that is -200°C, a nearly perfect vacuum, under low gravity, and with very little electrical power. That’s what we will have to overcome on the Moon,” Naicker said.

“If we can make the SonoChem System work there, we can make it work anywhere, whether that’s on Mars’ glaciers, or here on Earth in regions where accessing clean water is still a challenge.”

The prototype system adapts some commonplace items to demonstrate the technology. A wood pellet feeder normally used with barbecues continuously moves simulated regolith (building sand) into a domestic microwave, which Naicker previously said was going to be purchased from Tesco. Eventually, a robotic system will be used to feed the ‘hopper’ at the start of the process, with Naicker performing that role for now.

The system demonstrates the concept of continuous microwave heating of regolith, merging separate ideas investigated by NASA and the Open University. In the microwave, the soil is subjected to efficient volumetric heating that drives off frozen water and contaminants, leaving behind dry regolith. Dry regolith is continuously removed from the system and volatiles are directed to a secondary process for separation.

That process – sonochemical degradation – is a relatively new technology for water purification that is early in its adoption curve within the water industry and has not yet been used in space. It uses powerful soundwaves to spontaneously form millions of tiny bubbles in the collected water, creating extreme temperature (about 5,000ºC) and pressure (about 2,000 atmospheres) within each one. Those conditions are aimed at generating free radicals – unstable atoms which are highly chemically reactive – to effectively remove contaminants.

An experimental set up of a sonochemical reactor system, including an ultrasound transducer, has been built using laboratory grade equipment to create controlled conditions for testing.

Lolan Naicker harnesses the power of microbubbles (Credit: Max Alexander and Aqualunar Challenge)

Funded by the UK Space Agency’s International Bilateral Fund and delivered by Challenge Works – part of Nesta, the UK’s ‘innovation agency for social good’ – the Aqualunar Challenge’s £1.2m prize is designed to drive development of technologies that “make human habitation on the Moon viable by purifying water buried beneath the lunar surface”.

“NASA has set the goal of establishing a permanent crewed base on the Moon by the end of the decade,” Christian said. “The Artemis programme, as it is known, is supported by the UK Space Agency through its membership of the European Space Agency. Astronauts will need a reliable supply of water for drinking and growing food, as well as oxygen for air and hydrogen for fuel.”

The challenge is run in collaboration with the Canadian Space Agency and Impact Canada, with half the prize being awarded to UK-led teams, and half being awarded to Canadian-led teams.

Science minister Lord Patrick Vallance said: “By teaming up with our Canadian partners and harnessing the wealth of talent and creativity found across the UK, the challenge has uncovered a range of new ideas, including Naicker Scientific’s SonoChem system.

“Many of these ideas could not only fuel future space exploration, but also help improve lives and solve water shortages here on Earth – mitigating the impacts of climate change as we work towards a net zero future, a key ambition in our Plan for Change.”

Naicker Scientific was awarded the £150,000 first prize at a ceremony in Canada House in London’s Trafalgar Square, with two runners up winning £100,000 and £50,000 respectively.

The first runner up was Frank (Filtered Regolith Aqua Neutralisation Kit), developed by father and son team RedSpace, from Aldershot. The three-stage approach first heats the regolith sample in a sealed chamber to separate off volatile gases and leave a liquid of water, methanol and regolith fragments. The liquid is passed through a membrane to remove solid particles. The remaining liquid is distilled to separate the methanol from the water.

The second runner up was AquaLunarPure from Queen Mary University of London. In that process, a reactor melts lunar ice to separate the dust and rock particles, then heats it to more than 373°C at 220 bars of pressure to turn it into ‘supercritical water’ – a fourth state of matter that appears like a thick vapour – from which contaminants can be removed using oxidation.

The 10 finalist teams were each awarded £30,000 seed funding, expert mentoring and access to testing facilities in July 2024 to develop their technologies.

“Challenge prizes are open innovation competitions that level the playing field for innovators, whether they are well-established in a sector or coming to it for the first time – rewarding ideas rather than reputations. The Aqualunar Challenge successfully attracted new entrants to work in the space sector – a sector that already generates £19bn of income a year in the UK, but where there is great potential for growth,” said Holly Jamieson, executive director of Challenge Works.

“Competing teams have reported back that participating in the prize has helped them secure investment and open up commercial conversations to grow their businesses. There may only be one first prize, but the Aqualunar Challenge has produced many winners.”

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