Scientists want to turn moon dust into solar panels
Although solar panel technology was available during the NASA Apollo missions, none was used on any mission, whether en route to the Moon, orbiting it, or during lunar landing missions. Silver-zinc batteries or hydrogen-oxygen fuel cells were used instead. Part of the reason was based on weight vs. fuel, and part was based on the short-term needs. Even experiments performed on the Moon did not use solar panels. Depending on what phase of daylight the Moon was in, there was also a problem of being in total darkness for two weeks at a time. Skylab, established in 1973, was the first laboratory in space to use solar panels. Researchers are now reconsidering their use for long-term Moon bases that could potentially be established. Their concepts are meant to get around the problem of packing heavy panels for the one-way trip.
On September 12, 2023, I posted about NASA conceiving of a levitation system called FLOAT on the moon to transport materials. It involves a magnetic robot ore carrier system powered by solar panels. Bringing anything to the Moon (people, water, food, construction supplies, etc.) adds weight and high cost to each mission. But, if things could be made with lunar materials, that would simplify matters and lessen the costs. This concept is called In-Situ Resource Utilization (ISRU), whether it is being developed for the Moon, Mars, or any other body in space.
In a June 2025 article in Chemical Engineering Journal, examples are described for ISRU conversion of materials found on Mars to potentially make rocket propellants, water, and oxygen.
ISRU techniques have been considered even before the 1969 Apollo 11 moon mission. To date, none have ever been employed. It is considered too risky to depend on an ISRU technique to extract water as the only source for the astronauts, so just for safety, any missions that might take place would have to bring their own water as well as the equipment to extract it. Gerald Sanders (NASA Space Center) and William Lawson (NASA Kennedy Space Center) published a 2011 paper with 4 examples of testing ISRU on Earth.
The first was design and testing of a bulldozer blade called LANCE (Lunar Attachment Node for Construction and Excavation ), which was meant to flatten areas and scoop lunar "soil" (regolith) into protective barriers and landing pads, or to cover buildings and protect them from solar radiation. It was tested at the rolling sand dunes at Moses Lake, Washington (2008) and Flagstaff, Arizona (2009).
Sand dunes are different from lunar regolith. Something closer to that material is needed, so a second series of ISRU test were done at Mauna Kea, Hawaii in 2008. It had volcanic material (tephra) with a grain size and mineral properties similar to regolith. Two Lunar Outpost-scale Hydrogen Reduction process systems were built for mixing and heating with hydrogen, water vapor removal and collection, water electrolysis, and oxygen storage. A second one called ROxygen stirred and heated the regolith to extract oxygen.
In 2010, the third and fourth ISRU tests were performed, again at Mauna Kea. Part one had a different system (a solar concentrator) to melt regolith before extracting water, and this time water was electrolyzed into oxygen and hydrogen. Part two stored the hydrogen produced from water electrolysis tanks and later used it to power a solar concentrator and water electrolysis subsystems. The oxygen from the water was used to fire a small liquid oxygen/methane thruster to burn (sinter) volcanic ash into harder material and to power a communications display.
But what about building solar panels, not just extracting water and electrolyzing it, and not just piling moon regolith for construction purposes? Panels are far more complex. A panel consists of solar modules, which are each made up of solar cells.
The U.S. satellite Vanguard-1 (launched on March 17, 1958) was the first satellite ever to use solar power. It consisted of a spherical body 16.5 cm (6.4 inches) in diameter, with 30 cm (12 inches) long antennae forming an X shape. Its purpose was as follows:
- Test the launch capabilities of the Vanguard rocket system.
- Study Earth’s shape and atmospheric density by measuring its orbit.
- Serve as a test of solar cell technology in space.
Its chemical batteries provided 10 milliwatts of power to send data to Earth for early tracking and to help get Vanguard-1 into orbit. These died in 21 days as expected. Solar cells provided only 5 milliwatts and were less reliable, but they continued to operate to send data back for 6 years. The solar cells eventually failed due to radiation damage, temperature cycling, or electronics failure.
Improvements in solar cell technology were made over time to allow stronger power applications. For example, the International Space Station's 272,000 solar cells (in an area of about 27,000 square feet, or 2,500 square meters) generate hundreds of kilowatts of power (1 kilowatt = 1,000 watts = 1,000,000 milliwatts).
So, how do solar cells work and how are they constructed?
Each solar cell has two layers of silicon semiconductor: one has loose electrons flowing in it (N-layer), and the other has holes that can be filled by the electrons (P-layer). Photons from the sun pass through the protective glass coataing, then hit the area where these layers meet, knock off electrons, and start the process of electron flow. It moves through the N-layer out of the cell, to a place where it can be used or stored, and then back again to the P-layer through the aluminum sheet on the bottom if it isn't stored.
Recently, German scientists and engineers at the University of Potsdam have proposed two ways to improve the situation of sending heavy materials to the Moon to serve as solar panels. One is to use lunar regolith to make the glass component of solar cells, and the other is to use a promising new technology to make more efficient cells altogether.
Maria/Lowland material basalt because it was formed when meteors hit and allowed subterranean magma to rise up and fill the impact area. They are richer in iron and magnesium. Lunar terrae are older by 0.2-0.7 billion years and consist mostly of an igneous mineral called anorthosite, a type of feldspar with more alumina and lime. Which one is better to make "moonglass"?
Based on analysis of rocks returned by Apollo missions, the researchers at the Technische Universität Braunschweig (TUBS) in Germany used 100% materials from Earth to make simulated regolith from terrae and maria. They were called TUBS-T and TUBS-M for terra and mare simulants, respectively.
They melted each simulant at 1,500ºC in an electrical resistance furnace (think ultra-high-powered toaster oven capable of generating 3,000ºC). Because of the greater iron and titanium content, the TUBS-M material resulted in a black glass which did not permit light to pass. However, the TUBS-T material with more aluminum oxide and calcium oxide produced a yellowish transparent glass.
Optical and structural properties were similar to regular glass, although the yellow color reduced transmistion of light from 95% to 44%. Removing the iron with some sort of magnetic technology is thought to increase light transmission to 90-95%. But the presence of iron itself is actually a benefit that researchers will have to take into account before deciding how much to remove. Normally, a 0.1 millimeter-thick glass covers a solar cell in space, and although that's enough to protect the cell from radiation, it becomes damaged with extended radiation exposure, causing darkening and even cracks which affect the output of the cell. Glass can be treated to minimize this, but it is expensive. TUBS-T moonglass, however, seems to show radiation resistance due to the presence of its iron.
The University of Potsdam researchers also proposed a different way to make solar cells. Instead of using silicon, they conceived of perovskites. Perovskite (in the singular form) is a mineral of calcium, titanium, and oxygen (CaTiO3). But the word perovskites (in the plural form) is a generic name for a classification of minerals with the same crystal structure as perovskite, even though they may contain different elements to replace the three already there in its three-part structure. Pevroskites has a generic label of A, B and X in an interchangeble configuration with the same crystal shape.
Silicon-based solar cells, as shown above, have a positive and negative layer sandwiched together, and the sunlight activates the electrical charge where they meet. Pevrokite-based technology puts a pevoskite layer between two similar positive and negative layers of non-silicone material. When light hits the pevroskite, it energizes it to begin a flow of electrons to one of the other layers.
- Melting regolith would have to be done with a solar furnace, not an electric resistance furnace. That has to be shipped in pieces first, then assembled.
- TUBS-T was made on Earth to certain specifications, but samples of actual regolith may not be as pure.
- The mixing process for pevroskites may not be as uniform on the Moon with its 1/6 gravity of Earth. So, centrifugal or other types of mixing procedures need to be worked out.
- It is not known how evenly the pevroskite solution can be sprayed evenly with lighter gravity, and the apparatus needs to be shipped there.
- In addition to the moonglass and pevroskite (or silicon if pevroskite is abandoned) are still only 2 components of a solar cell and its larger version of a panel. Those materials also need to be sent.
