Ten teams of innovators, engineers and scientists developing new technologies to provide a permanent crewed base on the Moon with reliable water supplies have been named finalists in the Aqualunar Challenge.
The challenge is part of a £1.2 million international prize funded by the UK Space Agency’s International Bilateral Fund. A collaboration with the Canadian Space Agency (CSA) and Impact Canada, the UK track of the challenge is awarding finalist teams £30,000 each to develop their technologies before a winner and runners-up are announced in spring 2025.
Around the lunar south pole, it’s estimated that 5.6% of the soil (regolith) is water frozen as ice. For a permanent crewed base on the moon to be possible, astronauts will need a reliable supply of water for drinking and growing food, as well as oxygen for air and hydrogen for fuel.
If the lunar ice can be successfully extracted, separated from the soil and purified, it makes NASA’s goal of establishing a base by the end of the decade viable. The Artemis campaign, as it is known, is supported by the UK Space Agency through its membership of the European Space Agency.
“The ambition to build a sustainable human presence on the Moon through the NASA-led Artemis Missions will only succeed if we have ways of generating a reliable supply of clean water,” said Paul Bate, CEO, UK Space Agency.
“Space exploration pushes our knowledge to its limit and spurs innovation, resulting in new products and services that can also benefit citizens on Earth. Congratulations to all the finalists who will now go on to develop their ideas further.”
UK Space Agency reserve astronaut and chair of the Aqualunar Challenge judging panel, Meganne Christian, said: “It is expensive and risky to send a continuous convoy of rockets from Earth to the Moon to keep a base supplied, which is why we need to develop the technologies that can purify the water that is already on the Moon.
“The lunar environment is unforgiving. With no atmosphere and parts of the surface having never seen sunlight, the ice in the soil is as hard as steel and heavily contaminated with lunar dust – known as regolith – which forms a grinding paste when wet.
“It is no small feat to melt the ice, separate it from the dust and other elements and make it usable. The technologies being developed must have minimal maintenance – they cannot rely on components being sent up from Earth and it won’t be possible for astronauts to regularly change filters and tighten nuts and bolts.”
It is hoped that the technologies developed for the harsh environment of space will also be deployed on Earth, particularly in water-stressed regions and where access to clean drinking water is limited.
The finalists
AquaLunarPure: Supercritical Water Purification on the Moon – developed by Queen Mary University of London
A reactor would first heat lunar ice to leave behind dust and rock particles, then heat it to more than 373°C at 220 bars of pressure to turn it into “supercritical water” – not a solid, a liquid or a gas, but a fourth state that appears like a thick vapour – in which oxidation will remove all the contaminants in one step. Direct heating and insulation contribute to the high energy efficiency of this reactor, compared to current state of the art technologies.
Cyclic Volatile Extractor (CVE) – developed by Minima Design Ltd, Suffolk
The CVE will use a novel closed chamber to heat a batch of dirty ice to liberate volatile contaminants. The volume of the chamber can be actively changed to moderate its internal pressure. By regulating the temperature and pressure, different contaminants can be vapourised, liberated, collected and concentrated in separate storage systems.
FRANK – Filtered Regolith Aqua Neutralisation Kit – developed by RedSpace Ltd, Aldershot/Cleethorpes/Richmond (North Yorkshire)
A three-stage approach designed to deliver a continuous flow of drinking-grade water in a lunar environment would first heat the lunar soil (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.
Ganymede’s Chalice: Solar Concentrator Distillation for Clean Water Production – developed by British Interplanetary Society, London
A solar concentrator uses a curved mirror to focus the Sun’s rays on an air-locked crucible where lunar ice is placed by a small, automated crane. The heat from the concentrated rays boils the ice components one by one, and the system uses different storage mechanisms and chemical processes to store each component in safe and compact forms, finally condensing pure, drinkable water at the end.
I-LUNASYS: Innovative lunar water resource system – developed by Perspective Space-Tech Ltd, London
Using motorised pumps controlled by sensors, samples are heated at a constant pressure to separate and remove impurities as gas (isobaric vaporisation, followed by isothermal distillation). Using membranes and carbon filters, reverse osmosis separates the water molecules from the sample before entering a final UV filtration system. The system would be designed to be maintained by robots and could have new processes easily plugged into the system using “fluidic circuitry boards”.
Lunasonic – developed by Shaun Fletcher and Dr Lukman Yusuf, School of Chemistry, University of Glasgow
Dirty ice would be melted and large soil particles removed, before the water is pumped into a “sonoreactor” which uses ultrasound to split and remove volatile compounds and gases, destroy pollutants and cause lunar dust to clump together for easy removal. It then passes the water through a filter bed of lunar soil (rich in calcium, magnesium and aluminium oxides) to remove final contaminants – similar to how a household water filter works.
Regolith Ice Plasma Purifier for Lunar Exploration (RIPPLE) – developed by Regolithix Ltd, West Yorkshire
Dirty lunar ice would be fed into a reactor and heated to a water vapour. The vapour and solid regolith particles are fed into a vortex phase separator – similar to how a salad spinner flings water from lettuce leaves, the vortex flings the solid particles to the edge of the vortex to drop to the bottom while the gas exits from the top. The gas is fed into a plasma torch which breaks it into its constituent parts and a molecular sieve isolates the hydrogen and oxygen for water and fuel.
SonoChem System – developed by Naicker Scientific Ltd, Gloucestershire
The SonoChem System employs a groundbreaking core technology to purify water derived from lunar ice. Harnessing powerful sound waves, it spontaneously forms millions of tiny bubbles in contaminated water. The extreme temperature and pressure created within each micro bubble generates free radicals (unstable atoms which are highly chemically reactive) which effectively removes contaminants.
Static Water Extraction System (SWES) – developed by Interstellar Mapping, London
Lunar soil (regolith) would be fed into a reservoir. Using series of pressure seals and heating elements, different volatile substances in the sample that can be sublimated (i.e. turned from a solid into a gas without becoming a liquid) at lower temperatures than ice/water are extracted and stored, then the sample is heated again to turn the water to steam which is extracted and cooled. The system has no moving parts and is envisaged to operate for years with little maintenance.
Titania-Diamond Annular Reactor (TiDAR) – developed by Nascent Semiconductor Ltd, County Durham
The compact system employs a combination of UV light from LEDs to activate a titania catalyst and robust diamond electrodes, which are durable enough to endure the abrasive lunar soil and the G-forces experienced during launch. This combined system rapidly breaks down harmful organic and inorganic components in the lunar soil to create safe drinking water and even useful materials, such as rocket fuel from methanol.