GOLDEN, Colorado — Interlune, a Seattle-based company of former Blue Origin technologists, has set its sights on the moon’s supply of Helium-3 — a rare heavy isotope deposited into lunar regolith by solar wind that was found in samples brought back during NASA’s Apollo missions. More recent, astrogeological research, however, suggests significant technological and logistical challenges in harvesting this particularly scarce and difficult-to-extract isotope.
Specifically, a U.S. Geological Survey (USGS) astrogeologist said that harvesting the quantities of Helium-3 that Interlune envisions would require processing millions of tons of lunar regolith, an undertaking comparable to operating a copper mine on Earth.
Interlune CEO Rob Meyerson told SpaceNews that, despite initial skepticism even from the company founders, the company has identified uses for Helium-3 that justify the endeavor. The company now seeks to develop and deploy a harvesting system “akin to a terrestrial agricultural operation using five harvesters that are each the size of a large sport utility vehicle,” acknowledging that it would take years to make a financial return.
Highs and lows
“Helium-3 has been bombarding the surface of the moon for billions of years,” Meyerson told SpaceNews. “Over geologic time, meteorite impacts on the lunar surface have stirred up the fluffy regolith, with Helium-3 being distributed down to 3 meters [10 feet] in depth. That’s the depth that Jack Schmitt and two other crews got,” he said.
Schmitt, a geologist who walked on the moon during Apollo 17, is executive chairman of Interlune, founded in 2020 to harvest lunar resources.
Helium-3 now commands a stable price of around $20 million per kilogram, said Meyerson. Interlune is sharply focused near-term on extracting Helium-3 for superconducting quantum computing applications. The Helium-3 itself is used to cool the devices to as close a temperature to absolute zero as possible. “Quantum computing is the key demand generator for us.”
Meyerson explained that Helium-3 could also fuel nuclear fusion reactors on Earth — a use that Schmitt has championed in the past, though investors have shown little interest, prioritizing other applications such as quantum computing that would yield faster returns.
“We have ways we can go meet that need in the future,” Meyerson said, in addition to mining the moon for water, propellant, and industrial metals for in-space applications. Helium-3 can also be used in medical imaging purposes and radiation detecting technology.
Meyerson envisions meeting the demands of these industries by eventually harvesting and returning to Earth tens of kilograms of Helium-3 per year, he said, “and at that price and at the quantities we can produce, we think that’s sustainable.”
“Demand is growing and every quantum computer company we talk to recognizes the need and the future demand. That demand is going to start to come in the three-to-seven-year time frame,” said Meyerson. “And that’s why we think the time is now to go do this.”
Meyerson said that, despite the uneven distribution of luanr Helium-3, the company has ideas of where they should target based on data from NASA’s Lunar Reconnaissance Orbiter.
Meyerson declined to say where on the moon Interlune is targeting for competitive reasons, sharing just that it was near the equator. Meyerson added that Interlune won’t target the comparative abundance of Helium-3 in permanently shadowed regions near the moon’s south pole due to the difficulties of operating in that environment.
However, Laszlo Keszthelyi, a research geologist and lead spokesperson on lunar resources for the USGS Astrogeology Science Center in Flagstaff, Arizona, is less optimistic that lunar Helium-3 is as easily available for harvesting as Interlune would like.
Keszthelyi recently led a USGS assessment of lunar resource exploration that classified lunar Helium-3 “as an inferred unrecoverable resource” — it’s present, thanks to solar wind, but there’s a paucity of measurements to support its viability as an extractable resource.
Keszthelyi told SpaceNews that lunar regolith brought back during Apollo missions contained very small concentrations of Helium-3 ranging from 2.4 to 26 parts per billion, he explained.
“You have to process somewhere between 100,000 to 1 million tons [of regolith] to get a kilogram [of Helium-3], but it is there and it is measurable,” Keszthelyi said. “We do mining operations on Earth, such as copper mines that, in terms of size, are even larger.”
“As an agency, we like to provide reliable information and let other people do what they are going to do with that information,” Keszthelyi said. “There are resources on the moon. It’s a question of how you want to use those resources.”
Step-by-step
Interlune is now blueprinting a resource development mission, planned for 2027, to measure the concentrations of Helium-3 at a future harvesting site on the moon and test out extraction on a small scale. Interlune CTO Gary Lai previously predicted that Interlune would return only “single digit to 20 kilograms of product back to Earth within the early years of our operation.” That would be followed in 2029 by the establishment of a pilot plant on the moon “to prove out every step, including getting lunar-derived Helium-3 into the hands of our customers,” Interlune CTO Gary Lai said.
Meyerson said that the group’s first lunar mission will hitch a ride via the NASA Commercial Lunar Payload Services initiative.
“We’re in the design process right now and talking to potential partners,” said Meyerson. “We wouldn’t take up the whole payload. We are raising private capital to go do that. We’ve already raised about $18 million to date and we’ll be fundraising again next year.”
Meyerson said Interlune can generate revenue without NASA as the sole customer.
To test their hardware in low-gravity environments, Interlune has been booking flights with the Florida-based Zero-G Corporation, a private group that uses a modified B-727-200 aircraft to mimic lunar gravity conditions during parabolic dives.
Robotic Helium-3 harvesters
Interlune has developed patent-pending compact, energy-efficient processing machinery for use on the moon, which Meyerson says is designed to fit entirely into a single Starship mission.
“The Interlune harvester reaches just three meters into the lunar regolith and then redeposits the regolith back onto the moon’s surface, leaving the surface like a tilled field,” he explained.
In early October, the company announced a $365,000 grant from the U.S. Department of Energy to pursue new technology that would produce a Helium-3 supply by separating the isotope from terrestrial helium. Currently, the only way to acquire Helium-3 on Earth is to produce the hydrogen isotope tritium, which decays into Helium-3. The grant is intended to increase the Helium-3 supply in the short-term while advancing technology to harvest Helium-3 on the moon, which Meyerson said is their long-term strategy.
Interlune also received a NASA TechFlights grant to advance its proprietary technology to process lunar soil earlier this year. In 2023, the company was awarded a National Science Foundation Small Business Innovation Research Phase I grant to develop technology to size and sort lunar regolith.
The profitability question
Gerald Sanders, NASA’s the lead for NASA’s in-space resource utilization Capability Leadership Team, acknowledged that there’s a large terrestrial market for Helium-3, but suggested that it isn’t immediately apparent whether Interlune’s plans would be profitable.
Other experts say that Interlune’s success and profitability will depend on how efficiently the company’s machinery can till the lunar regolith, and what concentration of Helium-3 the company encounters.
“It is known that certain minerals tend to trap more He-3 than others,” Chris Dreyer, director of engineering at the Colorado School of Mines Center for Space Resource, said. “Thus, He3 concentration could be greater where these minerals are found.”
But, Dreyer added, profitability would require Interlune to process a huge swath of lunar landscape to find enough of the isotope.
“There are many challenges to mining He3. The large area to excavate and process for profitability is one,” said Dreyer. “Long duration operation in the presence of lunar dust will pose a challenge.”
That said, the way to solve these challenges is to build, test, and iterate, Dreyer told SpaceNews. “In a time when rockets are regularly flying to space and back …when rockets are being caught out of the sky… it’s not hard to imagine that Interlune can solve the technical challenges of He-3 mining,” he said.
Exhuming Helium-3 from the moon is a matter of concentration, depth and extraction efficiency, said Paul van Susante, a space resources specialist and assistant professor in Michigan Technological University’s department of mechanical and aerospace engineering .
“If they can dig deeper, say 10 meters, then the surface area needed can be reduced. If they can only excavate the top few centimeters,” Susante added, “obviously a much larger surface area would need to be processed,” he said and the total amount of Helium-3 per year would be different.
