Interlune

Helium-3 is genuinely scarce on Earth and genuinely abundant in lunar soil, where the solar wind has been implanting it for billions of years. Abundant is relative. It sits at roughly twenty to fifty parts per billion, so about 33,000 tonnes of regolith have to pass through a machine to yield a single gram. Interlune's answer is an excavator built with Vermeer that swallows a hundred tonnes an hour while moving continuously, feeding a sorter, a thermal extractor that bakes the volatiles out of the soil, and a separator.

Harrison Schmitt has been arguing for lunar helium-3 since the 1980s, and as the only professional geologist to have walked on the Moon he is difficult to dismiss on the geology. He co-founded the company with Rob Meyerson, who ran Blue Origin, and Gary Lai, who was chief architect of New Shepard. What has changed since the 1980s is the demand side: dilution refrigerators for quantum computers need helium-3 and cannot easily substitute it. Maybell Quantum, Bluefors and the Department of Energy have all agreed to buy, and Interlune puts its binding purchase agreements at close to half a billion dollars.

Almost nothing on the lunar side is demonstrated. The excavator has run on Earth, and no part of the chain has operated in vacuum, in one-sixth gravity, or in lunar dust. The US Geological Survey classifies lunar helium-3 as an inferred unrecoverable resource, meaning present but not shown to be extractable, and one of its astrogeologists has compared the required throughput to running a copper mine on the Moon. At the excavator's design rate a single machine yields something on the order of two hundred litres a year, so a ten thousand litre contract implies dozens of them running continuously. The first lunar mission is not a mining test but a camera, riding another company's rover on a lander that has slipped repeatedly. Meanwhile the clearest result Interlune has produced is Cold Capture, which pulls helium-3 out of ordinary terrestrial helium at 99 per cent purity and needs no Moon at all. Roughly twenty-eight people and something under $40 million raised stand behind delivery commitments that begin in 2029.