Can helium-3 create a ‘gold rush’ on the moon? | Scientific Americanhttps://www.scientificamerican.com/article/can-helium-3-create-a-gold-rush-on-the-moon/A kilogram of helium-3 costs roughly $20 million on Earth, where the entire planet produces only a few kilograms of it per year — almost all through the radioactive decay of tritium, a hydrogen isotope used to boost thermonuclear weapons. Scientists estimate that around a billion kilograms of the rare isotope lie embedded in the lunar surface, deposited over billions of years by the solar wind. That gap between terrestrial scarcity and lunar abundance is now driving serious commercial interest in moon mining, with Seattle-based Interlune among the companies positioning themselves to extract it.
The appeal is not speculative. Helium-3 is a superlative coolant that enables quantum computers to reach their operating temperatures — fractions of a degree above absolute zero — and is also essential for advanced medical imaging, for detecting smuggled nuclear material, and holds promise as a fuel for future fusion reactors. Writing in Scientific American, Robin George Andrews quotes Clive Neal, a lunar geoscientist at the University of Notre Dame, who draws a sharp distinction between helium-3 and other touted lunar resources such as water ice: "Helium-3 is where the money is".
The reason so much accumulates on the moon comes down to exposure and mineralogy. Earth's atmosphere and magnetic field deflect the solar wind; the airless moon has no such protection. Sara Russell, a planetary scientist at London's Natural History Museum, describes the result as helium-3 being "spray-painted across the whole of the lunar surface". Much of it is retained by ilmenite, a mineral composed of iron, titanium, and oxygen, which Neal describes as "a sponge" for solar-wind gases. The richest deposits are expected in mare regions — the dark, ancient lava plains — particularly in near-equatorial areas and, more often than not, on the lunar far side, where solar-wind exposure tends to be strongest.
Extracting the gas is considerably harder than locating it. "It's like trying to mine spray paint from a wall", Russell says. Interlune, founded in 2020, has developed a prototype extractor with industrial partner Vermeer Corporation capable of processing 100 metric tonnes of lunar regolith per hour. NASA awarded the company a $6.9-million contract earlier this month to advance its hydrogen- and helium-capturing technology. The company's robotic Prospect Moon mission, planned for as early as 2028, will carry a robotic arm, a mass spectrometer, and three different extraction devices. "That's what we need to demonstrate our business case for full-scale operations on the moon", says co-founder and CEO Rob Meyerson.
Not everyone is persuaded the enterprise is either viable or desirable. Russell raises environmental concerns about unregulated strip-mining leaving mechanical scars potentially visible from Earth. "The moon belongs to everybody, surely", she says. Meyerson counters that Interlune plans to dig to around three metres, leaving behind no waste or pollutants, describing the aim as "leaving the site looking like a tilled agricultural field" — though the article notes this is an optimistic projection that no one can yet verify in practice. Even NASA administrator Jared Isaacman has expressed scepticism, recently suggesting that asteroid mining may offer a greater return than lunar helium-3.
There are also open scientific questions with industry-defining stakes. If the solar wind replenishes the moon's helium-3 supply quickly, it could function as something approaching a renewable resource. If regeneration takes centuries or more, reserves may not keep pace with surging demand from quantum computing and other applications. "If helium-3 is a renewable resource, then you've got long-term prosperity", Neal says. Robotic prospecting missions — including NASA's VIPER rover, expected by next year, and the joint Japan-India LUPEX mission planned for 2028 — should begin to answer that question. "We're going to hit the mother lode", Neal ventures. "If it's proven, it could change everything."