Lunar Water
What We Know and What’s Still a Mystery
On Wednesday, January 16th 2025, a SpaceX Falcon 9 Block 5 launched two private lunar missions from Kennedy Space Center in Florida: the U.S.-led Blue Ghost Mission 1 ( Firefly Aerospace) and the Japanese-led HAKUTO-R M2 “Resilience” (ispace, inc.). If proof was still needed, this launch confirmed the geopolitical and strategic urgency of developing reliable lunar landers to deliver payloads to the Moon.
Firefly’s Blue Ghost aims to touch down on March the 2nd, carrying ten payloads, while ispace’s Resilience targets a landing in May-June with six payloads, including their own micro-rover, TENACIOUS.
Amid the excitement over the successful launch of these missions, it’s worth taking a moment to reflect on the bigger picture: why are we making all this effort? What goals are we trying to achieve, and how will the funding allocated over the next decade shape these ambitions? These questions underline the competitive drive among nations to establish technological and strategic dominance on the Moon.
If You Are Lazy
· How much water is on the Moon? We don’t know.
· Where is the water? In minerals, regolith, and polar ice caps.
· What can we do with lunar water? Drink it, irrigate with it, and turn it into rocket propellant.
· Want a good reference? Check out the USGS “Assessment of Lunar Resources Exploration in 2022”, an accessible summary of what we know—and don’t know—about lunar water.
· Which future missions should you follow? NASA’s PRIME-1 (planned for February 2025) and China’s Chang’e-7 (scheduled for 2026). Both target the South Pole with similar objectives.
Based on current estimates, a regolith containing 10 ppm of water would require around 100 truckloads to extract just one liter of water.
Lunar Landers Are Just the Start of a Long Journey
Lunar landers steal the spotlight, but let’s not forget they’re just the beginning of the process. Landers are merely delivery systems; they wouldn’t exist without payloads to carry or objectives to achieve once they reach the Moon.
Yes, the landing is the critical first step. But what happens next—payload deployment, data collection, transmission, and, most importantly, the interpretation and application of that data—is equally crucial. Unfortunately, much of this work remains hidden due to industrial and governmental secrecy or simply because what happens on the Moon sometimes literally stays there.
It’s also essential to view today’s progress within the broader context of history. While it feels like we’re making monumental strides, we’re still in the early stages of a very long journey. Consider this: over the past 60 years, humanity has attempted nearly 100 lunar landings with landers or rovers. Of these, only 26 were successful, and only six were crewed. Just one landed on the Moon’s far side, and only one (Intuitive Machines) was conducted by a non-governmental agency.
The vision of history changes with time. What seems groundbreaking today will someday be seen as just another step in the journey. Our aspirations to use the Moon as a stable base remain far on the horizon, and our path to achieving that goal is just beginning.
Building the Moon: The Blueprint for a Spacefaring Future
What are we trying to accomplish on the Moon? The ultimate goal is to transform the Moon into what Venice was for the world in the Middle Ages—a thriving hub for trade, exploration, and expansion—serving as a gateway to the rest of the solar system while bypassing Earth’s expensive gravity well.
To achieve this, we need to take several crucial steps: producing energy and materials directly on the Moon, creating in-situ structures, and developing robotic production systems that operate with minimal human oversight. Ideally, such systems would be coordinated by a handful of humans on or near the Moon and managed remotely from Earth.
To build this complex infrastructure, we must master how to manufacture essentials like energy, materials, and water directly on the Moon. Equally critical is establishing a reliable communication system that enables robots to work autonomously (in this sense Intuitive Machines really got the right name for the company). If we crack the code for constructing a remote industrial base on the Moon, we can replicate the process on Mars and other celestial bodies, moving closer to becoming an interplanetary species. After all, once you know how to build a boat, you can sail.
What Blue Ghost and Resilience Tell Us About Lunar Resource Extraction
Each component of the Moon strategy—minerals, energy, water, communication, life support, and propellant for future interplanetary missions—warrants detailed analysis because of the unique challenges involved. However, water stands out as a key variable, connecting many of these goals. It’s worth focusing on lunar water as a starting point.
A recent PNAS Special Feature, Water on the Moon and Mars, highlighted the critical importance of lunar water in the broader context of a lunar economy. Water isn’t just a resource—it’s the linchpin for enabling sustainable exploration.
Looking at the payloads aboard the Blue Ghost and Resilience landers, it’s clear that lunar water remains a high-priority area of study.
Resilience, for example, carries a water electrolyzer system developed by Takasago Thermal Engineering Co. This device aims to test electrolysis, a method for extracting oxygen from regolith. Resilience will land at Mare Frigoris (56°N latitude), a site identified by orbital remote sensing as potentially containing hydrogen-bonded molecules. These molecules may exist in impact glass within the soil or in the voids between regolith grains. The lander also carries the TENACIOUS micro rover, equipped with a shovel to collect lunar regolith samples for further analysis.
Blue Ghost, on the other hand, carries 10 payloads, at least two of which focus specifically on studying the regolith. The Lunar Instrumentation for Subsurface Thermal Exploration with Rapidity (LISTER), developed by Honeybee Robotics, will measure heat flow from the Moon’s interior by drilling to depths of 2–3 meters. This pneumatic drilling technology is a vital tool for exploring the presence of subsurface water. Blue Ghost also carries the Lunar PlanetVac (LPV), a regolith sample collector, and the Lunar Magnetotelluric Sounder (LMS), which will study the Moon’s mantle.
Lunar Water: What We Know and What We Don't
When scientists talk about “lunar water,” they’re referring to H-bearing molecules, which could exist as either OH molecules or H₂O. The key element here is hydrogen (H), as oxygen is relatively abundant. The challenge lies in identifying and quantifying the hydrogen needed to form water.
What we know about lunar water—H-bearing molecules in various forms—comes primarily from remote sensing via orbital instruments, with limited ground-truth validation. Another important source of data is the Apollo samples analyzed on Earth, which can provide a snapshot of water distribution in minerals in a specific location. As of today, we know that H-bearing molecules exist on the Moon, likely distributed throughout the soil, bonded to minerals, and trapped in the lunar ice caps—particularly in craters that are permanently shadowed. And that’s more or less the extent of what we know.
What we don’t know is how much water there actually is, in what form (as remote sensing cannot reliably distinguish between OH and H₂O), and how it is distributed spatially and vertically. It’s also unclear whether it’s a renewable resource or not. The long-held idea that the solar wind is the primary source of exogenous water has recently been called into question by a 2024 study by Thiemens et al.
Water in Minerals: Limited but Scientifically Significant
H-bearing molecules are present in various geological features. According to Prof. Andreas Pack, a co-author of a recent paper by Fischer et al. study and Professor of Geochemistry and Isotope Geology at the The University of Göttingen, in Germany, “Water within minerals is called indigenous water. It is bonded to minerals and is too sparse and inaccessible for human exploration.”
This indigenous water is found in minerals like olivines, volcanic glasses, apatite, and anorthosite. Measured on Earth using Apollo samples, it is crucial for understanding the Moon’s evolution and the origin of its water. However, its availability is so limited that it has little commercial potential for human use.
Regolith vs. Polar Ice: Where’s the Moon’s Real Water Supply?
The water of real interest for human exploration lies in two places:
The regolith (lunar soil), which contains H-bonded molecules.
The lunar polar caps, particularly in permanently shadowed craters at the poles.
H-bonded molecules in the regolith are either trapped in glass created by micrometeorite impacts or embedded in the voids between soil grains. These molecules have been identified at both low and high latitudes, using Apollo samples and remote sensing. Estimates suggest concentrations as low as 70 ppm at lower latitudes and up to 750 ppm at higher latitudes—amounting to less than 0.01 wt%.
A recent USGS report calculated that the global regolith layer (estimated to be 5–20 meters thick) might contain 30–100 billion metric tons of water-equivalent hydrogen, which means between 30 to 100 km³ (Lake Garda by comparison is 50 km³).
The Polar Ice Caps: A Speculative Treasure
The Moon’s polar craters—like Cabeus, Shackleton, Shoemaker, and de Gerlache—have been teasing scientists with hints of water since the 1960s. Evidence of water ice in these regions comes from various studies, but precisely mapping its location and quantity remains a challenge.
The only ground-truth measurement to date was made in 2009 by NASA’s LCROSS mission, which studied the plume created by an impact in Cabeus crater near the south pole. Analysis of the plume indicated that 5.6% of the material was water, with significant uncertainty (±2.9%). At the 95% confidence level, the water concentration could range from 0 to 11 wt% (Colaprete et al. 2010).
The USGS Report estimates that the lunar polar caps might contain 100 million to 1 billion metric tons of water ice—roughly the volume of 0.1 to 1 km³. For perspective, Lake Como holds 22 km³ of water.
The Realities of Water Extraction
It’s important to emphasize that all measurements regarding the quantity and distribution of water on the Moon remain highly speculative. However, with reasonable scientific certainty, we can say that H-bonded molecules are indeed present across the lunar surface, with their abundance increasing at higher latitudes.
While the soil component is more widely distributed and accessible, it comes in extremely low concentrations and requires significant processing to extract hydrogen from the rest of the regolith. Based on current estimates, a regolith containing 10 ppm of water would require around 100 truckloads to extract just one liter of water.
The ice component is potentially purer and may require less processing, but it is significantly harder to access due to the extreme cold in permanently shadowed craters and the steep, challenging terrain where the ice is located. Key variables, such as the thickness of the ice deposits and their depth, remain unknown.
Both water from regolith and water from ice caps are currently highly speculative resources, with uncertain availability for future lunar commercialization. Water ice, in particular, is considered speculative and likely unrecoverable at present. It is also viewed as a finite resource. In contrast, hydrogen bonded to soil appears to be a somewhat more stable (though still inferred and unrecoverable) resource that, if confirmed, might have a longer shelf life.
Lunar Propellant Production Plants
Lunar water has two immediate and transformative applications: supporting life through hydroponic cultivation and human necessities, and serving as propellant for future missions to the Moon and Mars. A 2019 paper published in REACH (Reviews in Human Space Exploration) examines the opportunities, challenges, and potential payoffs of a private business harvesting and processing lunar ice as the cornerstone of a lunar, cislunar, and Earth-orbit economy.
The paper outlines the entire lunar water mining value chain, from sampling and extraction methods to propellant storage and the power required to operate a full-scale lunar propellant production plant. The study estimates an annual demand for 450 metric tons of lunar-derived propellant, which equates to processing 2,450 metric tons of lunar water and generating $2.4 billion in revenue annually.
The Next Leap?
Despite promising remote-sensing data, uncertainties remain about the availability and distribution of water and hydrogen-bonded molecules on the lunar surface. Bridging this knowledge gap will require rigorous studies and targeted funding over the next decade.
In this context, the cancellation of VIPER—the most compelling unmanned mission designed to confirm the presence of lunar ice—is perplexing. While speculative discussions about lunar water persist, the one mission that could have provided definitive answers has been shelved. For now, hopes rest on a series of upcoming missions:
Blue Ghost and Resilience: Currently en route, with the aim to land and provide initial insights into regolith physical characteristics.
NASA’s PRIME-1 (2025): A polar resource ice mining experiment targeting lunar volatiles.
Chang’e 7 (2026): A Chinese mission equipped with a rover for in-situ volatile and isotope analysis.
Canadian Lunar Rover Mission (2026 or later): The only mission planning to explore permanently shadowed regions for up to an hour.
ESA’s PROSPECT (2027): A drill aiming to detect icy volatiles up to one meter below the lunar south pole’s surface.
LUPEX (2028): An Indian-Japanese mission to study water distribution and quality in the south pole region.
These missions reveal significant geopolitical trends. Major space powers—such as the US, China, India, Europe, and Japan—are converging on the lunar south pole to assess volatiles, highlighting the global interest in determining whether investment in lunar water resources is worthwhile.
The private sector is also preparing for confirmation of lunar ice’s commercial viability. The 2019 REACH paper and the advanced instruments from companies like Honeybee Robotics, a Blue Origin Company and Takasago Thermal Engineering, featured on Blue Ghost and Resilience, suggest the industry is ready to pivot quickly if data confirm the resource’s potential.
While these missions share common objectives, they employ diverse approaches to test capabilities, instruments, and connectivity. From in-situ laboratories to -200°C survival tests for rovers, every aspect is being pushed to its limits.
With the US and China preparing to launch missions in 2025 and 2026, the race is intensifying. However, the road to large-scale commercial production is still long. We’re likely five to ten years away from a clear understanding of water distribution on the Moon, and 30 to 40 years from achieving commercial-scale production.
A bibliographic list of the articles I consulted to create this summary:
Colaprete et al., (2010), Detection of Water in the LCROSS Ejecta Plume, Science v. 330
Reiss P. (2024), Exploring the lunar water cycle, PNAS v. 121 N. 52 (2024)
Spudis P., (2018), How Much Water Is On the Moon?, Air & Space Magazine
U.S. Geological Survey (2023), Assessment of Lunar Resource Exploration in 2022, Circular 1507