Power infrastructure will be critical for any long-term space colony, and one of the most critical pieces of that power infrastructure, at least in the inner solar system, is solar cells. So in-situ research experts were thrilled when Blue Origin, ostensibly a rocket company, recently announced that they had made functional solar cells entirely out of nothing other than lunar regolith simulant.
The process, which the aptly named Blue Alchemist, has been in the works for some time. According to a press release, Blue Origin has been working on making solar cells and necessary support components, such as wire and cover glass, all from regolith since 2021.
At its heart is a relatively simple process – molten regolith electrolysis. Basically, that means that blue origin uses electricity to split constituent atoms from the oxygen they are bound to in the lunar soil. Normal electrolytic cells separate water into hydrogen and oxygen, but Blue Alchemist takes the process a step further and separates elements such as iron, aluminum, and, most importantly, silicon from the oxygen they are bound to on the lunar surface.
One advantage of this process is that the “waste” product is oxygen – itself an invaluable material for lunar exploration, both as a component of breathable air, but also a potential rocket fuel. Silicon is the basis for not only solar cells but also glass, which needs to cover solar cells on the Moon to allow them to last more than a few days in the harsh radiative lunar environment. And iron and aluminum are useful for structural materials and conductive wire, in aluminum’s case. All this comes from the “dirt” that completely covers the surface of the Moon.
Blue Origin went so far as to make their own lunar regolith simulant to prove their process works rather than buying one already commercially available. They seemed to think that the commercially available simulants were too similar to a mish-mash of “lunar-relevant oxides” that didn’t truly represent the material found in the samples brought back by the Apollo mission and others.
Whatever their inputs, their process seems impressive, resulting in 99.999% pure silicon of the type used to make effective solar cells. Even more impressively, they did all of this “with zero carbon emissions, no water, and no toxic ingredients or other chemicals.” As the company rightfully points out, that kind of process could be useful even here on Earth if they find enough of a supply of oxides similar to those on the Moon.
But for now, this is a considerable step forward in the ISRU space. If used properly, it will form the basis of power infrastructure throughout most, if not all, of the lunar power infrastructure that long-term human exploration programs will need. That in itself is impressive enough, notwithstanding any benefits, it might have back here on our own blue marble.
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A picture of the Blue Alchemist solar cell.
Credit – Blue Origin