Deep inside a locked laboratory at Lancaster University, rows of beer kegs sit on shelves, linked by spindly copper pipework. They do not contain prize ale. Instead, they hold one of the most expensive materials on Earth: helium-3, a gas that costs roughly $2,000 (£1,500) per litre. The lab has been running for half a century, and as Dima Zmeev, a senior lecturer, explains, “Back then, the helium was quite cheap. Our very wise predecessors stocked up.”
Helium-3 is an isotope of helium, distinct from the cheap version that fills party balloons. It is crucial for cutting-edge technologies: quantum computing and nuclear fusion. But the main source today is tightly controlled – it comes from the decay of tritium inside nuclear weapons. Around the world, tens of thousands of litres of helium-3 are likely produced this way every year, estimates David McCollum, a distinguished scientist at Oak Ridge National Laboratory in Tennessee. But future demand could far exceed that supply.
“Lancaster University stores helium-3, a $2,000-per-litre gas crucial for quantum computing, which may soon be mined on the moon.”
Zmeev uses the gas in physics experiments, such as filling tiny chambers to detect dark matter particles. When a dark matter particle strikes a helium-3 atom, the atoms jiggle, generating heat that can be measured. The helium-3 can be reused again and again. Mixed with helium-4 at ultralow temperatures, it creates the coldest known environment in the universe – down to the millikelvin range (-273C). This cooling effect, called dilution refrigeration, is essential for quantum computers and could one day power nuclear fusion reactors.
As supply tightens, some entrepreneurs and researchers argue that new sources are needed. Helium-3 exists on Earth in the ground, but at very low concentrations. However, samples of moon dust, or regolith, from the Apollo missions suggest it may be present on the lunar surface at relatively high concentrations. Plans are now afoot to recover helium-3 from the moon.