The European Space Agency’s sustainability chief revealed that research into using lunar regolith for solar panel production was accelerating as germanium shortages threatened traditional space power systems.
The European Space Agency (ESA) is researching the use of lunar regolith (moon soil) for solar panel production as part of its strategy to address critical mineral supply challenges that threaten space-based power systems, according to the agency’s Chief Climate and Sustainability Officer.
In an exclusive interview with Fastmarkets at the Economist Impact 10th anniversary Sustainability Week conference held in London from March 10-12, 2025, Andrea Vena, ESA’s sustainability chief, revealed that the agency is actively studying alternatives to traditional germanium-based solar cells as export restrictions and price volatility create supply chain vulnerabilities.
The interview comes as ESA prepares to celebrate its 50th anniversary in 2025, marking five decades since European countries joined forces to pursue space exploration through collaboration.
“On the moon, we have an abundance of regolith,” Vena said. “This is the main material, and we are studying the possibility [of using] regolith for solar panels because those are the ones that can give energy to our satellites.”
The research is increasingly relevant as germanium, a key material for space-based solar applications, faces significant supply pressures following China’s implementation of export controls in August 2023.
However, outside of resource utilization on the moon, regolith itself is not typically considered a suitable alternative to germanium. The metal, primarily extracted from zinc ore, is a semiconductor material used in electronics and solar panels.
“For us, mining and exploitation of resources will be necessary if we want to increase our knowledge of other celestial bodies,” Vena said. “It is not conceivable that we are bringing everything from Earth. If we have to put a base there, we have to learn to use materials that are in place and we bring technologies to reuse materials.”
Germanium supply vulnerabilities
Germanium’s primary space application is as a substrate for gallium arsenide solar cells, which are core to space photovoltaic technology. Each standard satellite requires approximately 6,000-15,000 germanium wafers for high-efficiency solar cells, with larger satellites requiring about tens of thousands, according to Nebula Public Library, the knowledge bank of ESA’s research and development programs.
Fastmarkets sources anticipate strong demand for germanium wafers in the satellite sector, driven by increasing satellite launches. A market source told Fastmarkets in December 2024 that production processes result in raw material losses, meaning germanium wafer supply won’t increase at the same rate as raw material availability.
China implemented export controls on germanium-related items on August 1, 2023, leading to a sharp decline in exports and global supply chain disruption, with export levels yet to return to pre-control figures, according to Chinese customs data.
European price trends have reflected this supply disruption. Fastmarkets’ most recent price assessment for germanium 99.999% Ge min, in-whs Rotterdam was $3,000-3,300 per kg on March 26, up by 114% from $1,400-1,550 per kg on August 2, 2023.
Germanium was listed among the top 10 priority materials that could face significant supply chain disruption, according to the UK Criticality Assessment published by the UK Critical Minerals Intelligence Centre on November 28, 2024.
“If you take the example of germanium, that has been the basis for solar panels for years, now we can use other… replacement materials that can be used instead,” Vena said. “Already today we are studying biomaterials that can replace on Earth germanium and gallium arsenide to make our solar panels for space.”
Circular economy approach for space exploration
Vena emphasized that circularity principles are fundamental to ESA’s approach to space exploration.
“For me, as a sustainability practitioner, I would say that fundamental for the future space exploration is circularity. We have to learn to reuse, recycle, repurpose and redesign as much as possible the resources that are in situ,” he said.
This approach addresses the challenges posed by germanium supply constraints. According to ESA documentation, standard triple-junction solar cells are grown on a foundation of 150 micrometers of germanium — a rare and expensive material amounting to around 30% of the cost of each individual cell. However, only 10-20 micrometers are actively used, creating significant waste.
To address this inefficiency, ESA has been supporting projects to recover and recycle germanium. One such initiative, completed in 2021, implemented a recycling process that allows for 80% of the germanium to be recovered from manufacturing processes.
Gallium nitride: Promising space semiconductor
ESA is also investing in gallium nitride (GaN) technology as a “key enabling technology for space.”
In 2022, the ESA described the radiation-resistant GaN as the most promising semiconductor compound since silicon, operating better at much higher voltages and temperatures than comparable materials such as silicon and the widely-used gallium arsenide (GaAs).
In 2024, Andrew Barnes — overseeing ESA’s work in GaN — has said on official ESA platforms that “In terms of communications for space, GaN offers a five- to ten-fold increase in communications power, while requiring no additional cooling systems.”
Fastmarkets assessed gallium 99.99% Ga min, in-whs Rotterdam at $600-690 per kg on March 26, unchanged from the previous session on March 21. This represents an increase of approximately up to 68% from $350-420 per kg on August 2, 2023, before China implemented its export controls.
AI data centers in space
Vena revealed that ESA is investigating broader energy innovations that could transform space exploration and benefit Earth.
“If we find a way to generate power that can be used on Earth from space, we are going to solve a lot of problems on Earth because this is going to be the real renewable energy,” he said.
One concept involves positioning data centers in space to reduce Earth’s energy consumption. “Data centers with artificial intelligence coming are going to be the major source of electrical consumption on Earth,” Vena predicted. “The idea is to put them in space. They are closer to power, and they are in very cold temperature, so there is no real need to cool them down.”
“And then you have to transfer the data from space to Earth, but this is something that we [already] know we can do,” Vena continued. “So there are real projects in place for putting data center farms in space. This is something that is under development.”
However, Vena pointed to the problem of space debris.” We have a lot of space debris orbiting around the Earth… [becoming] more and more crowded,” he said. “Without a responsible approach to that, we have no business up there.”
Vena acknowledged the technological challenges ahead. “There are many challenges — the technology that is needed to capture the energy, the technology that is needed to transfer the energy and the power,” he said, but remained optimistic: “Nobody was thinking even 100 years ago that we could ever land on the moon and we have done it. It is a matter of investment and it is a matter of working together.”
According to Vena, major European aerospace companies including Airbus and Thales are exploring these concepts, with ESA providing technical oversight and funding through contracts that represent 85% of the agency’s budget. Fastmarkets confirmed Airbus and Thales among the entities which have received more than €15,000 of EU funds in the form of a Copernicus Space Component contract in 2024.
