Posted on

Extraction of oxygen from lunar regolith using solar pyrolysis

Experimental apparatus of an experiment to characterize solar pyrolysis of lunar regolith simulant, a) Flowchart of the setup with the reactor, solar concentrating system and the various peripheral equipment, b) Picture of the pyrolysis reactor during sample exposure to concentrated solar energy. Note glass reactor clouding due to the deposition of the vaporized materials. Credits: Figure 2 with minor text edits from article by Jack Robinot et al. / Used under CC by 4.0

A team of European researchers have for the first time, quantified oxygen production via solar pyrolysis, a process that uses concentrated sunlight to heat lunar soil to release oxygen as a gas. Jack Robinot and collaborators report their results in Advances in Space Research. The findings of this study mark a significant milestone in space manufacturing technology, providing the first-ever direct experimental quantification of oxygen yield from the thermal decomposition of lunar regolith using focused solar energy.

As space settlement advocates are aware, the primary bottleneck for long-term human habitation on the Moon and elsewhere in the solar system is the logistical challenge of resupply of resources from Earth. They know that In-Situ Resource Utilization (ISRU) is the key to long term sustainability by harvesting and processing local materials into valuable resources like oxygen, water, and metals.

Oxygen is obviously of particular importance, not only because it’s needed for human life support, but also for rocket fuel. Liquid oxygen typically constitutes approximately 80% of the mass of rocket propellant. Producing oxygen directly on the Moon could dramatically reduce the cost of lunar and deep-space missions by eliminating the need to transport heavy fuel up from Earth’s gravity well. And of course it is a component of breathable air for settlers.

The lunar surface is covered in regolith composed mainly of silicate minerals and metal oxides. Despite the absence of an atmosphere, oxygen is the most abundant element on the Moon, making up about 45% of the regolith by weight.

When comparing the over twenty techniques that have been proposed for oxygen extraction—including carbothermal reduction and molten salt electrolysis—most require imported consumables like hydrogen or methane. Solar vacuum pyrolysis is advantageous because it:

  • Requires no consumables as it utilizes only solar energy and natural vacuum, both in abundance on the Moon.
  • Reduces logistics as there are no reagents to recycle or transport from Earth.
  • Lowers reaction temperatures because the low pressure of a vacuum environment favors the reduction of metal oxides, allowing the process to occur at more manageable temperatures.
  • Provides high efficiency via solar concentrators which can deliver high thermal power densities (up to 350 W/kg) without the energy conversion steps required by electrical systems.

By way of historical context, the concept of vaporizing lunar regolith was first explored in 1971 using samples of lunar soil returned by Apollo 12. Early researchers like Steurer (1982) proposed the theory of solar pyrolysis, calculating potential yields of 17%, but no solar experiments were conducted at that time.

Subsequent studies by Senior (1992) and Šeško (2024) successfully heated simulants and observed qualitative evidence of oxygen release, such as pressure increases or changes in material composition. However, technical challenges—including glass window breakage and the limitations of mass spectrometry—prevented these researchers from precisely quantifying the amount of oxygen produced. The current study bridges this gap by introducing a new analytical method using a trace analyzer to quantify oxygen within a carrier gas.

Before conducting experiments, the researchers modeled the behavior of heated lunar regolith through thermodynamic analysis of EAC-1 simulant (European Astronaut Centre-1, a high-fidelity lunar regolith simulant developed by the European Space Agency). They used the Gibbs energy minimization method via HSC Chemistry 10 (a process modeling platform widely used in the metallurgical and chemical industry). The model simulated the behavior of EAC-1 regolith simulant—which closely matches the oxygen content of real lunar soil (approx. 44%)—under temperatures up to 3000°C and pressures ranging from 10 mbar to 3 X 10-15 bar.

The key findings of the analysis included:

  • Temperature Dependence: At a pressure of 10-2 bar, the optimal reaction temperature was roughly 2600°C.
  • Pressure Impact: Lowering the pressure significantly reduces the required reaction temperature. At lunar surface pressures, the reaction could occur at temperatures as low as 950°C.
  • Oxygen Species: High temperatures and low pressures promote the formation of monoatomic oxygen (O), though this study focused on quantifying diatomic oxygen (O2).

The researchers noted that while the model provides a “target” for yield, it assumes a closed system at equilibrium. In practice, the experimental reactor will be an open system where species are constantly removed, shifting the equilibrium to promote further reduction via Le Chatelier’s principle.

Digging in to the setup and methodology, the experiments were conducted using a specialized solar reactor at the French national laboratory PROMES (Procédés, Matériaux et Énergie Solaire, or in English, Processes, Materials and Solar Energy), which is managed by the French National Centre for Scientific Research (CNRS).

The components of the apparatus included:

  • Solar Concentrator: A 2-meter diameter parabolic dish focusing sunlight into a 2 cm focal spot.
  • Tracking and Control: A heliostat provided real-time solar tracking, and a system of shutters precisely modulated the solar flux delivered to the sample.
  • Reactor Chamber: A glass vacuum sphere where the regolith pellet sat on a water-cooled steel holder.
  • Gas Analysis: An argon carrier gas was injected to sweep released oxygen into a high-precision oxygen trace analyzer (0.1 ppm to 1% range).
  • Condensation System: A refrigerated copper condenser and a porous stainless steel filter captured volatilized metal species to protect the vacuum pump.

The procedure was initiated by placing a 3.38-gram pellet of EAC-1 simulant in the reactor. The chamber was evacuated and then pressurized with 10 mbar of argon. Solar power was increased in stages with the following observations:

  1. 380 W: Initial melting was observed, but no oxygen was released.
  2. 650 W: A brief oxygen peak occurred, likely due to the reduction of volatile oxides like Na2O and K2O.
  3. 1200 W – 1460 W: Sustained oxygen production began as the sample reached approximately 1800°C.

The key results of the experiment achieved the first direct determination of oxygen reaction yield for this process:

  • Total Oxygen Extracted: 35 mg.
  • Mass Yield: 1.05% of the total processed sample weight.
  • Extraction Efficiency: This represents 2.47% of the total oxygen available within the regolith simulant.
  • Energy Yield: Approximately 31 mg of O2 per kWh.

The study observed that oxygen production happens in distinct stages: an early release during initial melting followed by a more sustained extraction period at peak temperatures. During the process, the vaporized material caused visible “opacification” (clouding) of the reactor’s glass window, which likely reduced the amount of solar energy reaching the sample toward the end of the run.

For characterization of the by-products, after the experiment the researchers analyzed the remaining residue and the deposits found throughout the reactor using SEM/EDS, XRD, and Raman spectroscopy.

With respect to mass balance, of the original 3.38 g sample, 1.82 g remained as a “glassy residue” on the holder, while approximately 1.1 g was vaporized and deposited elsewhere. The final mass recovery was 92%.

An elemental and phase analysis revealed:

  • Residue: Contained non-volatile elements like Aluminum (Al), Calcium (Ca), and Titanium (Ti), along with some Magnesium (Mg) and Silicon (Si).
  • Deposits:
    • On the holder: High concentrations of Sodium (Na) and Iron (Fe).
    • On the window: Primarily Silicon (Si) and Iron (Fe).
    • On the condenser: Mostly Silicon, with some Iron and Magnesium.
  • Crystalline Phases: XRD analysis of the original EAC-1 sample showed it was highly crystalline (containing minerals like augite, forsterite, and anorthite), whereas the residue present in the experiment was largely amorphous glass.

In the Discussion section of the paper the researchers found that the experimental yield of 1.05% was slightly lower than the 1.37% predicted by the thermodynamic model for conditions of 10 mbar at 1800°C. The discrepancy was attributed to several factors:

  1. Open vs. Closed System: The model assumes everything stays in the reactor, while the experiment continuously pumps gases out.
  2. Kinetics: Real-world reaction rates and temperature distributions within the pellet are not accounted for in basic equilibrium models.
  3. Argon Dilution: The argon carrier gas is a “double-edged sword.” While it allows for accurate quantification and prevents oxygen from recombining with metals, its presence increases the total pressure, which works against the pyrolysis reaction.

Although these numbers do not sound significant, the study demonstrates that solar vacuum pyrolysis is a viable, reagent-free method for extracting oxygen from lunar regolith. Beyond oxygen, the results suggest that fractional separation of metals is possible, as different elements vaporize and condense at different locations and temperatures. These findings are promising to inform follow-on studies to develop in-situ metal refining processes to provide feedstock for building lunar infrastructure.

Future work will focus on lowering operating pressures to further increase oxygen yield, customizing the reactor to allow for high carrier gas flow without increasing total chamber pressure, and development of advanced kinetic models that account for temperature gradients within the regolith.

By successfully quantifying the oxygen yield, this research achieves an important benchmark for designing the next generation of hardware intended to support a sustainable human presence on the Moon. Once scaled up, solar pyrolysis factories could supply breathable air in situ for hotels like those planned by GRU Space and other dwellings in communities envisioned by Lunar Cities, a StellarWorld company.

Illustration depicting a stroll down a boulevard with shops, cafes and restaurants in an underground lunar community called District 1 planned by the company Lunar Cities, which could be supplied with oxygen harvested from lunar regolith via solar pyrolysis. Credit: Lunar Cities

Posted on

Room with a view on the Moon

Artist rendering of what could be the first hotel on the Moon. Credit: Galactic Resource Utilization Space

Galactic Resource Utilization (GRU) Space published a white paper in January outlining their ambitious plans for a combination lunar base and hotel on the Moon. They believe this plan will accelerate humanity’s transition to an interplanetary species. Authored by the founder of the startup Skyler Chan (a recent UC Berkeley graduate with experience in space hardware and software), the document critiques the current state of the space industry and proposes a private-sector-led approach centered on lunar tourism as the catalyst for broader infrastructure development. GRU Space, backed by Y Combinator, was founded last year.

Chan asserts that humanity stands at a pivotal moment where becoming an interplanetary civilization is achievable within our lifetimes. He argues that the current legacy space ecosystem relies heavily on two pillars: government-subsidized exploration (such as NASA’s Artemis program) and massive launch capabilities (e.g. the Space Launch System and SpaceX’s Starship). However, a true commercial “lunar economy” remains virtually nonexistent. The industry suffers from a stagnation cycle—companies wait for government contracts to fund development, while agencies demand proven hardware before committing funds. This creates a deadlock where advanced technologies (e.g. lunar robotics, power systems, comms) exist in isolation without real customers or demand drivers.

GRU Space rejects this dependency on slow government timelines and “customer discovery” phases. Instead, the company aims to create immediate, tangible value for people on Earth to jumpstart economic activity off-world. Their core thesis: space tourism, specifically a lunar hotel, is the fastest and most practical “wedge” to bootstrap a self-sustaining lunar economy. Chan’s proposed solution: GRU Space’s flagship project to build and operate the first hotel on the Moon, initially as a high-end tourism destination for short multi-day stays. This hotel would serve paying customers (with reservations already open for deposits ranging from $250,000 to $1 million) while simultaneously demonstrating and de-risking technologies essential for permanent lunar infrastructure. GRU’s innovations and phased approach include:

  • Mission I (2029): A small ~10 kg payload delivered via a Commercial Lunar Payload Services (CLPS) lander to test core habitation technologies, particularly an inflatable structure featuring an airtight bladder, structural fabric, micrometeoroid shielding, and thermal/UV protection layers.
  • Mission II (2031): Deployment of a lunar cave base using inflatable systems positioned near a lunar pit or lava tube skylight for natural radiation shielding and resource access. Although not in their current plans, this could pave the way for eventual pressurization of a lava tube for habitation, a concept that has already had preliminary studies completed and covered by SSP.
  • Mission III (2032): Delivery of the first operational lunar hotel via a heavy-lift launch vehicle and lander, accommodating up to four guests initially (with plans to scale to 10 in later versions) located in scenic locals, featuring stunning views of Earth and thrilling extravehicular activities.

The initial hotel will be constructed from inflatable modules shipped from Earth. Future expansions will transition to in-situ resource utilization (ISRU)—processing lunar regolith into durable bricks or structures using automated robotic systems. This reduces launch costs dramatically and enables scalable construction of roads, warehouses, mass drivers (proposed by Elon Musk recently), and other base elements including locally sourced oxygen. GRU’s team is staffed perfectly for these technologies. Cofounder and Member of Technical Staff Kevin Cannon is a planetary geologist and an authority on ISRU. He’s been the source for several posts on SSP and will know exactly where and how to access lunar resources needed for the effort.

The lunar hotel is envisioned to be a high-end destination that generates revenue from customers coming up from Earth, while simultaneously validating ISRU, habitation and life support technologies for more expansive infrastructure.

GRU Space’s broader vision after the hotel positions the company as an architect of long-term human presence on the Moon and Mars with a technical roadmap progressing as follows:

  • Solve the problem of off-world surface habitation via the hotel
  • Expand to support a full base with infrastructure including roads, resource processing, and storage.
  • Replicate the model for population centers on Mars for millions of people.

The approach leverages commercial transportation (e.g., from SpaceX or Blue Origin) and focuses on creating goods/services with Earth-side value (tourism experiences) to generate revenue and prove viability. This contrasts with government-led efforts by prioritizing private customers and rapid iteration.

Overall, the document combines technical roadmap details with economic philosophy, emphasizing self-reliance, revenue-driven development, and urgency in seizing the current window for interplanetary expansion. While ambitious and early-stage (with no operational hardware as of yet), it reflects a startup mindset applied to space settlement, backed by expertise in ISRU, robotics, and space systems from the founding team.

Chan concludes the white paper with a bold claim: by building the first lunar hotel, GRU Space will outflank the traditional space industry, create the initial spark for a lunar economy, and lay the groundwork for humanity’s multi-planetary future. He frames the project not merely as tourism but as a civilizational necessity—turning the Moon into a stepping stone for permanent, expanding human settlement beyond Earth. The last step in his “Top Secret” GRU Master Plan is humanity becoming a Kardashev Type III civilization! Now we know how he came up with the name!

Posted on

Modeling an ISRU-based energy storage system for sustainable lunar electricity production

Illustration of a Lunar ISRU Energy Storage and Electrical Generation concept (not to scale). The system utilizes three heat transfer fluid circuits. The collection loop in the receiver tube is heated by sunlight from a field of mirrors during the lunar day and circulates to the thermal mass raising its temperature. Upon lunar nightfall, a discharge loop transfers heat from the thermal reservoir to the Stirling engine for electricity production. While the engine is running a thermal regulation loop dissipates heat through the radiator. Credits: system layout by Mario F. Palos and Ricard González-Cinca, modified to add component labels; lunar landscape by Grok 2

One of the difficulties of designing solar power systems for use on the Moon is the challenge of energy storage during the 14 day lunar night at lower latitudes far from the peaks of eternal light at the poles. Such systems would benefit from technology that leverages in situ resource utilization (ISRU) for this critical function rather then expensively transporting batteries from Earth. It would be ideal to model these systems prior to use via computer simulations to optimize the design before bending metal. In the journal Advances in Space Research, Spanish physicists Mario F. Palos and Ricard González-Cinca explore this approach in a paper that examines an ISRU-based system for energy storage and electricity generation.

The architecture of the proposed system, dubbed Lunar ISRU Energy Storage and Electrical Generation (LIESEG), collects solar energy during the lunar day via a mirror field to concentrate sunlight on a receiving pipe containing a heat transfer fluid (e.g. molten sodium). The heated fluid flows to a thermal mass raising the temperature of the energy reservoir. The resultant stored thermal energy from the reservoir is discharged through a second fluid loop used to drive a Stirling engine for electricity production during both day and night. A third heat rejection loop thermally regulates the system by transferring heat from the cold side of the heat engine to the radiator. This modular design balances efficiency and durability under extreme lunar conditions.

The ISRU implementation angle of the study emphasizes the use of lunar regolith and other local materials to minimize reliance on Earth-based supplies. This not only reduces launch costs but also aligns with long-term sustainability goals for lunar habitats.

To analyze the LIESEG system performance, simulations were carried out using EcosimPro software, a tool used by the European Space Agency in multiple aerospace applications, to assess power output, efficiency, and scalability. A comprehensive theoretical model based on the thermodynamics of the subsystems under lunar conditions was developed to analyze the energy flow and efficiency of the system. The study evaluated the specific power performance (power output divided by launch mass) of the system, highlighting its potential to be superior to other conventional methods like photovoltaic systems or nuclear reactors in terms of mass efficiency and sustainability. It also discusses the influence of key factors like the thermal conductivity of lunar regolith, the size and orientation of solar collectors, and the efficiency of the Stirling engine.

The authors conducted a detailed trade-off analysis of technologies, considering criteria like transportability, installation complexity, operational reliability, scalability, and lifespan. Solar collection and thermal conversion technologies were highlighted as critical components for achieving operational stability.

The proposed LIESEG system offers a promising approach for sustainable energy production on the Moon, potentially reducing reliance on Earth-launched resources and enabling longer, more autonomous missions. The system’s feasibility was demonstrated through computer modeling whose results show LIESEG to be practical for initial lunar missions with lower energy needs, as well as for later advanced bases requiring higher power outputs (up to 100 kWe and beyond). This research shows that a LIESEG system has merit for planning future development of energy infrastructure supporting initial lunar outposts and eventually, permanent settlements on the Moon.

Posted on

Lunar Outpost Eagle to fly on Starship – blazing a trail for lunar highways

Artist rendering of the Lunar Outpost Eagle Lunar Terrain Vehicle. Credit: Lunar Outpost

Space News recently reported that Colorado-based Lunar Outpost has signed an agreement with SpaceX to use Starship to deliver their lunar rover, known as the Lunar Outpost Eagle, to the Moon. Announced November 21, the contract supports the Artemis program with surface mobility and infrastructure services. The agreement positions Starship as the delivery vehicle for Lunar Outpost’s Lunar Terrain Vehicle (LTV), which is a contender for NASA’s Lunar Terrain Vehicle Services (LTVS) program. The exact terms of the contract, including the launch schedule, were not disclosed in the announcements. Lunar Outpost has assembled a contractor team under the banner “Lunar Dawn” to execute the company’s LTV solution. The collaborative development program includes in industry leaders Leidos, MDA Space, Goodyear, and General Motors.

Rover Design Features

  • Mobility and Functionality: The Lunar Outpost Eagle is designed to support both crewed and autonomous navigation on the lunar surface. It’s built to operate even during the harsh lunar night, exhibiting resilience against the Moon’s extreme temperature changes.
  • Collaborative Development: The Lunar Dawn team brings expertise in spacecraft design, robotics, automotive technology, and tire manufacturing, ensuring a robust and versatile design.
  • Size and Capacity: Described as truck-sized, the Eagle LTV is intended to be a valuable vehicle for lunar operations, capable of transporting heavy cargo to support NASA’s Artemis astronauts and commercial activities.
  • Testing and Refinement: The design has undergone human factors testing at NASA’s Johnson Space Center, with feedback from astronauts being used to refine the vehicle’s usability and functionality.

Future Plans

  • NASA’s LTV Program: Lunar Outpost is one of three companies selected by NASA for the LTV program to develop rovers to support future Artemis missions. The other two companies are Intuitive Machines and Venturi Astrolab. After a preliminary design review (PDR), NASA will select at least one company for further development and demonstration, with the goal of having a rover operational in time for Artemis 5, currently scheduled for 2030.
  • Commercial Operations: Beyond NASA’s usage, the rovers will be available for commercial operations when not in use by the agency, aiming to support a sustainable lunar economy. This includes plans for infrastructure development and scientific exploration.
  • Series A Funding: Lunar Outpost has recently secured a Series A funding round to accelerate the development of the Lunar Outpost Eagle, ensuring that the rover project moves forward regardless of the outcome of NASA’s selection process.
  • Long-Term Vision: The company’s vision extends to enabling a sustainable human presence in space, with plans to leverage robotics and planetary mobility for development of infrastructure to harness space resources.

This partnership with SpaceX and the development of Eagle under the Lunar Dawn program are pivotal steps in advancing both NASA’s lunar exploration goals and commercial activities on the Moon.

Once delivered to the Moon by Starship, the Eagle rover will drive over harsh regolith terrain which, as discovered by Apollo astronauts when driving the Lunar Roving Vehicle, presents several unique challenges due to the Moon’s distinct environmental conditions. First, lunar dust is highly abrasive and can become electrostatically charged sticking to surfaces and mechanisms resulting in wear and degradation of wheels, bearings, and sensors potentially leading to equipment failure. The Moon’s low gravity can make traction difficult. Rovers might slip or skid becoming less stable when accelerating, braking or turning. Terrain variability and nonuniformity on loose powdery dust or sharp, rocky outcrops could cause stability issues.

These problems can be solved by creating roads with robust, smooth surfaces for safe and reliable mobility on the Moon. Initially, the regolith could be leveled by robots with rollers to compact the regolith to make it less likely to be kicked up by rover wheels. Eventually, technology being developed by companies like Ethos Space for infrastructure on the Moon using their robotic system for melting regolith in place for fabricating lunar landing pads, could be used to build smooth, stable roads.

A network of roads could be constructed to transport water and other resources harvested at the poles to where it would be needed in settlements around the Moon extending from high latitudes down to the equatorial regions. As envisioned by the Space Development Network, this system of roads could be created to provide access to a variety of areas to mine valuable resources as well as thoroughfares to popular exploration and tourism sites. The development of the highway system could start at the poles with telerobots, then eventually be expanded to include equatorial areas and would be fabricated autonomously prior to the arrival of large numbers of settlers.

Longer term, a more efficient method of transportation on the Moon could be magnetic levitation (maglev) trains. Research into this technology has already been proposed by NASA which is actively developing a project named “Flexible Levitation on a Track” (FLOAT), which aims to create a maglev railway system on the lunar surface. This system would use magnetic robots levitating over a flexible film track to transport materials, with the potential to move up to 100 tons of material per day. The FLOAT project has advanced to phase two of NASA’s Innovative Advanced Concepts (NIAC) program.

Artist’s rendering of the Flexible Levitation on a Track (FLOAT) maglev lunar railway system to transport materials on the Moon. Credit: Ethan Schaler / Jet Propulsion Laboratory
Posted on

ESA launches the Second Space Resources Challenge

Conceptual illustration of lunar regolith extraction and beneficiation operations creating feedstock for an oxygen production factory on the Moon. Credits: Grok 2

The European Space Agency (ESA) on October 24 initiated their Second Space Resources Challenge. The Space Resources Challenge is an initiative aimed at stimulating innovation in the field of in-situ resource utilization (ISRU) for lunar and potentially other planetary bodies’ development. Launched in partnership with the Luxembourg Space Agency and their joint European Space Resources Innovation Centre (ESRIC), the competition encourages participants from various backgrounds—including students, startups, and established companies—to develop technologies that can collect, process, and utilize resources on the Moon. The challenge focuses on extracting valuable resources like oxygen for human life support and rocket fuel, as well as metals for construction, from lunar regolith. By fostering a competitive environment, ESA seeks to advance technologies that could reduce the dependency on Earth-supplied materials, thereby making long-term lunar missions more economically viable. The competition not only aims to develop new ISRU technologies but also to build a community of innovators interested in the value of space resources, potentially leading to commercial opportunities in the burgeoning space economy.

Launched on October 24, the second Challenge will focus on extraction and beneficiation of lunar regolith, critical steps in establishing a sustainable human presence on the lunar surface. Teams have until February 20th 2025 to submit proposals. Competition winners can claim €500K for the best performing team and will be awarded a development contract for a feasibility study. A second place prize worth €250K will be awarded to the best team in the category of beneficiation.

The first Challenge, which targeted resource prospecting, took place in 2021 and featured a competition between robotic protypes in ESA’s Lunar Utilisation and Navigation Assembly (LUNA) facility, an advanced research and simulation center designed to support Europe’s efforts in lunar exploration. Located within ESA’s European Space Research and Technology Centre (ESTEC) in the Netherlands, LUNA serves as a testing ground for technologies and systems intended for lunar missions. The facility includes a moon-like environment where various aspects of lunar landing, operations, and human habitation can be simulated.

The Second Resource Challenge will focus on:

  • Extraction: The collection, hauling and handling of lunar regolith. In LUNA this will be modeled using lunar simulant, which mimics the Moon’s soil. The problem to be solved in this area of the challenge involves designing robotic systems that can collect and transport material efficiently in the harsh lunar environment.
  • Beneficiation: a term adapted from the terrestrial mining industry, is the process whereby the economic value of an ore is improved by removing the gangue minerals, resulting in a higher-grade product. In the context of ISRU on the Moon, beneficiation will convert regolith into a suitable feedstock through particle sizing and mineral enrichment, preparing it for the next step in the value chain. On the Moon the next process could be extracting valuable resources like oxygen for life support and rocket fuel, and metals for construction or manufacturing, which will be essential for sustaining a long-term human presence on the Moon.

The technology development program will award the teams with the most innovative robotic systems that exhibit autonomy, durability, efficient handling and processing of regolith in the extreme conditions of vacuum, temperature extremes and dust expected in the lunar environment.

Alignment with Strategic Roadmap:

The Second Space Resources Challenge is a pivotal part of ESA’s Space Resources Challenge strategic roadmap to build out the ISRU Value Chain. The next phase of the program will focus on “Watts on the Moon”, i.e. reliable surface power sources for lunar operations. Subsequent phases will develop ISRU applications including extraction of oxygen and water for life support and rocket fuel, with the goal of sustainable in situ factories in the 2030s providing resource supply chains for settlements and the cislunar economy. Integrated systems downstream in the Value Chain, such as Pioneer Astronautics’ (now part of Voyager Space) Moon to Mars Oxygen and Steel Technology (MMOST) application to produce oxygen and metallic iron/steel from lunar regolith, are already under development.

Space Resources Challenge strategic roadmap depicting gradual progression of ISRU development activities. Challenges are planned to be solicited every three years. Credits: ESA

The Second Space Resources Challenge competition is a critical forward-thinking step in ESA’s plans for space development. By concentrating on the extraction and beneficiation of lunar regolith, ESA is not only preparing for the logistics of long-term lunar habitation but also setting a precedent for how future space missions might operate autonomously and sustainably. This challenge underscores ESA’s commitment to innovation, sustainability, and the strategic use of space resources, paving the way for humanity’s next steps in the settlement of the Moon and other worlds in the Solar System.

Update October 2025: This month the challenge resulted in a field test at the LUNA facility. Eight teams demonstrated robotic systems designed to collect and process lunar regolith. The participating teams hailed from six countries including Canada, Denmark, Germany, Luxembourg, Poland and the United Kingdom. A contract for detailed design development will be awarded by ESA next month to the most promising team, which could see flight hardware for mission to the Moon (timeline dependent on future funding).

Posted on

Ethos Space has ambitious plans for the Moon and beyond

Conceptual illustration of a SpaceX Starship on a lunar landing pad made from in situ materials by Ethos Space, which plans to use lunar resources for space development. Credits: Starship image: SpaceX; Lunar landing pad and landscape: Grok 2

Kevin Cannon, one of our favorite researchers on ISRU here on SSP, recently appeared on The Space Show to discuss his new position as Senior Lunar Geologist for Ethos Space, a Los Angeles based lunar infrastructure startup that just emerged from stealth last June. Near term (by 2028), the company plans to support the Artemis program by attempting to robotically building landing pads for Starship using lunar regolith, an application SSP covered last year in a ground breaking trade study. Ethos also hopes to extract oxygen from lunar regolith which makes up 80% of rocket propellant and could be a major market segment in a cislunar economy. Incidentally, a few years ago Cannon looked into where on the Moon is the best place to source oxygen.

Long term (20 – 30 years from now) Ethos hopes to use lunar materials to manufacture a sunshade commissioned by world governments that would be placed at the L1 Sun-Earth Lagrange point to combat global warming by blocking 2% of sunlight that reaches our planet. Ethos Space CEO, Ross Centers, is founder of the nonprofit Planetary Sunshade Foundation which issued a report on the state of space based radiation modification about a year ago.

Conceptual illustration of planetary sunshade fabricated from materials sourced on the Moon. Credits: Ethos Space
Diagram depicting the proposed location for a sunshade located at the L1 Sun-Earth Lagrange point (not to scale). Credits: Planetary Sunshade Foundation
Ray trace showing that the more acute umbra shadow of a sunshade would not reach Earth while the diffuse penumbra is what would cover our planet (not to scale). Credits: Planetary Sunshade Foundation

Cannon believes that a sunshade is a better geoengineering solution to cool the climate then cloud seeding with sulfur dioxide aerosols as at least one startup company, Make Sunsets, is proposing. Cannon believes this approach, which he says amounts to “using pollution to fight pollution”, will not be very popular with the general public. Make Sunsets counters this argument with an analysis available on their website showing that sulfur dioxide released high in the stratosphere is highly effective in counteracting the warming effect of carbon dioxide while dispersing to negligible levels globally reducing the chance of producing acid rain, the primary concern of sulfur releases in the lower atmosphere. In fact, a paper in Geophysical Research Letters published last August documents evidence that recent regulations on cargo ship emissions limiting sulfur pollutants may have actually contributed to global warming. In 2020 the International Maritime Organization (IMO) instituted new regulations reducing the maximum allowed sulfur emission per kg of fuel in ships by 80%. As a result, artificial clouds created by ship emissions decreased causing northern hemisphere surface temperatures to rise. This example reinforces the need to study geoengineering projects carefully to prevent unforeseen consequences. With respect to the sunshade, Cannon anticipates that international coordination will definitely be required as some countries may have farm land that would actually benefit from anticipated warming so may not want these regions shaded.

Back to the Moon: On The Space Show podcast Cannon mentioned that Ethos will be partnering with Astrolab, a Hawthorne, California based company which has already been awarded a NASA contract to develop a Lunar Terrain Vehicle for the Artemis program. Astrolab’s current concept, dubbed FLEX, is designed to carry two suited astronauts, has a robotic arm for science excavations, and can survive the extreme temperatures at the Lunar South Pole. The rover can be teleoperated remotely from Earth or driven by suited astronauts. The Ethos robotic system for fabricating lunar landing pads would be towed behind this rover while melting the regolith in place forming molten stripes over multiple passes that cool into igneous rock that would be very robust. The mechanism for how the regolith will be melted was not disclosed but if they are guided by the trade study mentioned above, microwave sintering makes the most sense.

Image of Astrolab’s FLEX rover which may tow the Ethos Space robotic system for melting lunar regolith to fabricate landing pads on the Moon. Credits: Astolab

In a post a few years ago on his blog Planetary Intelligence, Cannon makes the case that mining Luna for platinum group metals (PGM) would be more economically feasible than from near-Earth objects (NEO) because of transit times and operational difficulties due the typical NEO being an “…irregular shaped rubble pile–or basically a space sandcastle of loose dust and boulders–held weakly together by cohesion and microgravity, and spinning rapidly.” In addition, terrestrial ore grades are higher than in NEOs potentially making the economics challenging to compete with mines on Earth. The CEO of asteroid mining company Astroforge, Matt Gialich, begs to differ. He thinks there is a business case for mining NEOs and has venture capital backers that agree. Cannon actually collaborated with Gialich on a paper making the case for mining PGMs from main belt asteroids which SSP covered last year. However, the distances involved make near term profits difficult, and Astroforge is now focusing on NEO’s relatively close to Earth. Gailich also appeared on The Space Show this year and addressed the terrestrial ore grade question when I posed it to him, essentially saying that extraction of PGMs from NEOs could be economically competitive with terrestrial mines because they are so deep and have slim profit margins.

Both Ethos and Astroforge will have mission results in the next decade, although they are targeting completely different markets. Hopefully, both will succeed.

Posted on

Using energy from space to power in situ resource processing on the Moon

Conceptual illustration of a Lunar Power Station beaming power to facilities on the Moon for energy intensive in situ resource processing . Credit: Astrostrom GMBH

Settlements on the Moon will eventually need to “live off the land” via in situ resource utilization (ISRU). This approach is essential to make settlements economically feasible and self sustaining, obviating the need to expensively import materials up out of Earth’s gravity well. Before we can utilize resources in situ on the Moon we need to understand how to process them there. Researchers at the University of Waterloo in Toronto, Canada are developing technologies for in situ resource processing (ISRP) of lunar soil to produce useful materials, but they will need power. Lots of it.

In a paper presented last October at the 74th International Astronautical Congress in Baku, Azerbaijan, Waterloo Department of Mechanical and Mechatronics Engineering Master of Science Candidate Connor MacRobbie and Team describe how a space-based solar power (SBSP) satellite in lunar orbit could provide the juice for several energy hungry processes that could generate consumables and building materials from lunar regolith.

The study includes a survey of the scientific literature on lunar regolith processing techniques under development, some with experimental results, that would benefit future lunar settlements. Using electrolysis, chemical reduction, pyrolysis and other reactions these methods can be used to extract metals, oxygen, water and other useful commodities from lunar regolith. The techniques have well established pedigrees on Earth, but will need further development for efficient operations on the Moon and will require very elevated temperatures. Thus, the need for an abundant power source like SBSP.

One such promising process is Molten Regolith Electrolysis (MRE). In this method, lunar soil is heated to the melting point in an electrolytic cell. When voltage is applied across the cathode and anode in the cell, the molten regolith decomposes into metal at the cathode and oxygen at the anode, both of which can be collected and stored for use by settlers. No inputs or materials are needed from Earth, only a local power source to melt the untreated regolith.

One of MacRobbie’s supervisors is Dr. John Wen, director of the Laboratory for Emerging Energy Research (LEER) at Waterloo. With the help of Wen and LEER, the Team developed a novel material processing method for MRE. In molten regolith solutions, the constituents and their oxides can be separated by an applied voltage enabling extraction from the solution. Because each individual oxide decomposes at different values, stepping the voltage will facilitate sequential removal and collection of the lunar soil constituents, e.g. iron, titanium, aluminum, silicon, and others; which can be utilized for building and manufacturing. The new method could reduce the cost of processing and provide purer end products. The Team will continue working with LEER on the design of the equipment toward proof of concept with small batches aiming for accurate and repeatable successive extractions of materials using MRE. The only remaining step would be to qualify flight-ready hardware for experiments on the Moon.

In another project LEER is investigating lunar regolith as an input to a power source in space for heating or manufacturing. The embedded metal oxides in lunar soil, when combined with a metal like aluminum, produce thermal energy via a thermite reaction. The aluminum could be sourced from defunct satellites in Earth orbit which has the added benefit of helping to address the orbital debris problem.

Other groups like Swiss-based Astrostom GMBH with their Greater Earth Lunar Power Station are already working on SBSP solutions to provide ample power for lunar surface settlements which could provide sufficient electricity for Waterloo’s ISRP technology. The Astrostom approach would place the power satellite at the L1 Earth-Moon Lagrange point, a location between the Earth and Moon at a distance of 60,000 km above lunar surface. Although not a gravitationally stable location, the station would could maintain a fixed point above a lunar ground station on the Moon’s nearside with minimal station keeping propulsion systems.

Posted on

JAXA’s Lunar Farming Concept Study

Cutaway illustration depicting a sublunar farm covered by regolith, providing food and augmenting life support for a settlement on the Moon. Credits: Microsoft Image Creator

The Japan Aerospace Exploration Agency (JAXA) published a report last November summarizing the findings of its Lunar Farming Concept Study Working Group. JAXA’s team, composed of professionals in universities and private experts, assumes that humans will eventually establish permanent communities on the Moon and conducted the study using cutting-edge agriculture science and biotechnology to design a plant factory that would provide nutritional sustenance and oxygen in a life support system for a lunar settlement.

The working group was composed of four subgroups: cultivation, unmanned technology, recycling, and overall system design. The cultivation subgroup focused on the farm’s environmental controls including light levels (provided by LEDs), irrigation and atmospheric conditions tailored to each crop type. The unmanned technology team dealt with robotic maintenance of the plant factory environment including autonomous monitoring, sowing, cultivating and harvesting. The recycling group ensured soil improvement and reuse of limited resources, inedible scraps and waste material. Finally, the overall system subgroup studied the farm as a whole taking into account each plant species.

The scale of the lunar colony in the study was spit into two scenarios. An initial settlement in the near future with a 6 person crew followed by a larger scale permanent community at a later date with 100 people. The objective was to define a scalable cultivation system that would provide energy and nutritional requirements for settlers without resupply from Earth. The design would leverage recycling to fullest extent possible, minimize the use of materials sourced on the Moon such as water and oxygen from the polar regions, and reduce supplies imported from Earth, realizing that the system would not be 100% closed. LED lighting was utilized to optimize wavelength for chlorophyll absorption as well as diurnal growth cycles during the 14 day lunar night, being necessary for crop illumination in an underground farming community protected from radiation by thick layers of regolith. Nuclear power was considered as a power source.

An important finding of the study leveraged a metric called the Equivalent Systems Mass (ESM), to evaluate the life support systems of the different lunar farm designs explored by the team. ESM is a mathematical formula used to perform trade studies to determine which options have the lowest launch cost and is calculated from the system variables mass, volume, power, cooling, and crew working hours. When comparing the ESM of several biomass production systems it was found that the mass of the system could be minimized by appropriate sizing of crop cultivation shelves and increased space utilization efficiency. It was shown that over a 10 year period an optimized design for a lunar farm would not have to be replenished with food from the Earth when building materials, water and oxygen were supplemented by sources on the Moon and nuclear power was assumed as a power source.

The JAXA study adds to the space farming body of knowledge needed for establishing life support systems for space settlement.

Posted on

Greater Earth (GE⊕) Lunar Power Station

Conceptual illustration showing the first iteration of the proposed design of a GE⊕ Lunar Power Station beaming power to facilities on the Moon. Credit: Astrostrom

In response to ESA’s Open Space Innovation Platform Campaign on Clean Energy – New Ideas for Solar Power from Space, the Swiss company Astrostrom laid out a comprehensive plan last June for a solar power satellite built using resources from the Moon. Called the Greater Earth Lunar Power Station (GE⊕-LPS, using the Greek astronomical symbol for Earth, ⊕ ), the ambitious initiative would construct a solar power satellite located at the Earth-Moon L1 Lagrange point to beam power via microwaves to a lunar base. Greater Earth and the GE⊕ designation are terms coined by the leader of the study, Arthur Woods, and are “…based on Earth’s true cosmic dimensions as defined by the laws of physics and celestial mechanics.” From his website of the same name, Woods provides this description of the GE⊕ region: “Earth’s gravitational influence extends 1.5 million kilometers in all directions from its center where it meets the gravitational influence of the Sun. This larger sphere, has a diameter of 3 million kilometers which encompasses the Moon, has 13 million times the volume of the physical Earth and through it, passes some more than 55,000 times the amount of solar energy which is available on the surface of the planet.”

GE⊕-LPS would demonstrate feasibility for several key technologies needed for a cislunar economy and is envisioned to provide a hub of operations in the Greater Earth environment. Eventually, the system could be scaled up to provide clean energy for the Earth as humanity transitions away from fossil fuel consumption later this century.

One emerging technology proposed to aid in construction of the system is a lunar space elevator (LSE) which could efficiently transport materials sourced on the lunar surface to L1. SSP explored this concept in a paper by Charles Radley, a contributor to the Astrostrom report, in a previous post showing that a LSE will be feasible for the Moon in the next few decades (an Earth space elevator won’t be technologically possible in the near future).

Another intriguing aspect of the station is that it would provide artificial gravity in a tourist destination habitat shielded by water and lunar regolith. This facility could be a prototype for future free space settlements in cislunar environs and beyond.

Fabrication of the GE⊕-LPS would depend heavily on automated operations on the Moon such as robotic road construction, mining and manufacturing using in situ resources. Technology readiness levels in these areas are maturing both in terrestrial mining operations, which could be utilized in space, as well as fabrication of solar cells using lunar regolith demonstrated recently by Blue Origin. That company’s Blue Alchemist’s process for autonomously fabricating photovoltaic cells from lunar soil was considered by Astrostrom in the report as a potential source for components of the GE⊕-LPS, if further research can close the business case.

Most of the engineering challenges needed to realize the GE⊕-LPS require no major technological breakthroughs when compared to, for example (given in the report), those needed to commercialize fusion energy. These include further development in the technologies of the lunar space elevator, in situ lunar solar cell manufacturing, lunar material process engineering, thin-film fabrication, lunar propellent production, and a European heavy lift reusable launch system. The latter assumes the system would be solely commissioned by the EU, the target market for the study. Of course, cooperation with the U.S. could leverage SpaceX or Blue Origin reusable launchers expected to mature later this decade. With respect to fusion energy development, technological advances and venture funding have been accelerating over the last few years. Helion, a startup in Everett, Washington is claiming that it will have grid-ready fusion power by 2028 and already has Microsoft lined up as a customer.

Astrostrom estimates that an initial investment of around €10 billion / year over a decade for a total of €100 billion ($110 billion US) would be required to fund the program. They suggest the finances be managed by a consortium of European countries called the Greater Earth Energy Organization (GEEO) to supply power initially to that continent, but eventually expanding globally. Although the budget dwarfs the European Space Agency’s annual expenditures ( €6.5 billion ), the cost does not seem unreasonable when compared to the U.S. allocation of $369 billion in incentives for energy and climate-related programs in the recently passed Inflation Reduction Act. The GE⊕-LPS should eventually provide a return on investment through increasing profits from a cislunar economy, peaceful international cooperation and benefits from clean energy security.

The GE⊕-LPS adds to a growing list of space-based solar power concepts being studied by several nations to provide clean, reliable baseload energy alternatives for an expanding economy that most experts agree needs to eventually migrate away from dependence on fossil fuels to reduce carbon emissions. Competition will produce the most cost effective system which, coupled with an array of other carbon-free energy sources including nuclear fission and fusion, can provide “always on” power during a gradual, carefully planned transition away from fossil fuels. The GE⊕-LPS is particularly attractive as it would leverage resources from the Moon and develop lunar manufacturing infrastructure while serving a potential tourist market that could pave the way for space settlement.

Posted on

Artificial photosynthesis for production of oxygen and fuel on the Moon and Mars

Image of ice in a crater on the Martian plain Vastitas Borealis captured by the European Space Agency’s Mars Express orbiter. Credits: ESA/DLR/Freie Universitat Berlin (G. Neukum)

When we establish outposts and eventually, settlements on the Moon or Mars it would be economically beneficial if we did not have to create supply chains from Earth for water, breathable air and the fuel we will need for our rockets. This is why sources of water ice in the permanently shadowed craters at the lunar poles and in glaciers in the equatorial regions on Mars are so attractive as early destinations. Once we get there what equipment will we need to process this valuable resource? The typical way envisioned for cracking water in situ on the Moon or Mars to produce oxygen and hydrogen is through electrolysis. But this method requires a lot of power. There may be a more efficient way. New ESA sponsored research by scientists* in the UK and Europe examines a novel method that mimics photosynthesis in plants using a photoelectrochemical (PEC) device. The findings were published June 6 in Nature Communications.

PEC reactors are currently being studied on Earth for water splitting to produce green hydrogen from sunlight. Since they only rely on solar energy for power they are ideal for space applications. One type of device consists of a semiconductor photocathode immersed in an electrolyte solution that absorbs solar energy for a reaction to split hydrogen from water molecules. Oxygen is produced at the anode of the cell. PEC devices can be fabricated as panels similar to photovoltaic arrays. For use on Mars, the authors analyze another similar PEC technology using a gas-diffusion electrode to reduce atmospheric carbon dioxide in a reaction producing methane for rocket fuel.

The authors modeled the performance of these devices subjected to the expected environmental conditions on the Moon and Mars. Specifically, they looked at attenuation from the accumulation of dust on the PEC cells caused by micrometeorites pulverizing the lunar surface, coupled with the solar wind inducing an electrostatic charge in the resulting dust. And of course dust storms are relatively frequent on Mars which could significantly degrade performance. To address this problem self cleaning coatings are suggested as a solution. Solar irradiance was also considered as it would be reduced at the orbit of Mars. It was concluded that the PEC performance could be significantly boosted with solar concentrators by a factor of 1000 enabling higher production rates and power densities, especially on Mars.

An added advantage for space-based application of this technology is the elements needed to construct PEC devices are readily available on these worlds obviating the need to transport them from Earth and thereby significantly reducing costs.

“…in-situ utilization of elements on both, the Moon and Mars, is feasible for the construction of PEC devices.”

The technology is ideal to augment the production of oxygen in environmentally controlled life support systems of habitats that may not initially be 100% closed and cannot easily be resupplied with consumables from Earth. A competing technology for oxygen production which was recently demonstrated on Mars is the Mars Oxygen In-Situ Resource Utilization Experiment (MOXIE) which functions via solid oxide electrolysis of carbon dioxide. This process requires high temperatures and therefore, more energy presenting a challenge when increased production of oxygen will be required for large settlements. The author’s analysis show that the PEC devices are more energy efficient and can easily be scaled up.

“Oxygen production via unassisted PEC systems can … be carried out at room temperature … suitable to be housed in temperature controlled space habitats.”

* Authors of the Nature Communications article Assessment of the technological viability of photoelectrochemical devices for oxygen and fuel production on Moon and Mars: Byron Ross at the University of Warwick, UK; Sophia Haussener at Ecole Polytechnique Fédérale de Lausanne, Switerland; Katharina Brinkert, University of Bremen, Germany