Introducing the 10 technologies set to purify water frozen in the Moon’s soil

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.

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.

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.

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.

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”.

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.

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.

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.

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.

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.