Giant, regolith-based solar panels under development for ESA’s lunar outpost
Image credit: Guillermo Ferla | Unsplash
Researchers based at Estonia’s Tallinn University of Technology (TalTech) are working to develop technology for the production of solar cells to provide electricity to future lunar outposts of the ESA and its partners.
ESA hopes, over a timescale of decades, to establish a lunar output on the South Pole of the Moon. Previous Moon missions, such as Nasa’s Apollo or the Soviet Luna mission, landed relatively near the Moon’s equator, rather than in the rugged polar moonscape.
However, the Moon’s South Pole has been identified as the possible region for a future lunar outpost, given its perpetual exposure to sunlight and the possible existence of water (hinted at by recent orbiting missions).
At TalTech, scientists are hoping to contribute to this mission through the development of solar cell technology. The researchers have presented a sandpaper-like solar cell containing thousands of sunlight-absorbing microcrystals (diameter 50μm) embedded in a polymer, in one continuous layer. The microcrystals are then coated with a buffer and window layers, allowing each crystal to function as a tiny solar cell and generate electricity.
According to the scientists, this type of solar cell has many advantages over conventional solar cells. For instance, the solar cell technology combines the advantages of highly efficient mono-crystalline materials with low-cost roll-to-roll panel production. This enables the manufacture of flexible, lightweight and cost-efficient solar panels to cover huge areas at minimal cost; in theory, there is no limitation on the size and shape of solar panels that could be constructed using this approach.
As space agencies consider ambitious plans for crewed bases on other astronomical bodies, such as the Moon or Mars, they must consider how to sustain the base and its inhabitants using the materials available, such as developing additive manufacturing tools that work with regolith.
In this case, the microcrystals used in the monograin layer solar cell could be produced from elements found in the soil and regolith on the surface of the Moon. Specifically, the TalTech team suggest using pyrite (FeS2), better known as 'fool’s gold', creating solar cells with efficiency up to 25 per cent. The constituent elements of pyrite, iron and sulphur are quite abundant in the lunar regolith.
“TalTech scientists have been working on monograin-layer solar cell technology for terrestrial applications for a couple of decades already,” explained Dr Marit Kauk-Kuusik, head of the university’s photovoltaic materials lab. “The core innovation is the unique light absorbing layer made of the single-crystalline powder, which contains abundant and low-cost elements. Solar cells based on this technology will bring innovation to the building-integrated solar power field.”
According to the scientists, they started to work with ESA around six years ago, when they came across their monograin-layer solar cell technology and considered it potentially valuable for space applications. After their first collaborative project with ESA, they developed the idea of implementing the technology – using materials available in the lunar regolith – to power a future lunar outpost.
Madis Võõras, head of the Estonian Space Office, commented: “We are glad to see, that Estonian membership in the ESA brings practical results. It has opened the doors for PhD level scientists, and doctoral students, also for master level trainees who can work in ESA laboratories, and be part of the ESA science community. The benefit from that can’t be overestimated.”
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