Kilometre-high towers made of lunar concrete and covered in solar panels could potentially be used to power a crewed base on the moon.
The moon’s poles have long been eyed for human habitation. Both poles have regions known as “peaks of eternal light”, where sunlight shines almost constantly, while the south pole has an abundance of permanently shadowed craters that contain water ice.
These two features could theoretically provide solar power and liquid water for a crewed base, but the surface region of permanent sunlight is only a few square metres in size. At altitude, the area of sunlight is much larger, spanning several hundred square kilometres.
Sephora Ruppert at Harvard University and her colleagues suggest building towers on the moon to access this sunlight, using concrete made from lunar soil. The towers could be made by extracting sulphur from the lunar surface, mixing it with the soil and heating the mixture to bind it together.
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The moon’s low gravity means such towers could theoretically be built to great heights without buckling, so in practice the height is limited by the available materials.
The team found that a realistic height for such a tower would be 1 or 2 kilometres, requiring 760 and 4100 tonnes of concrete respectively, stacked in blocks like a concrete igloo. With wide bases tapering upwards, the towers could be covered in solar panels, generating large amounts of power.
“From half a kilometre to 2 kilometres, you can have several gigawatts,” says Ruppert.
Thanks to the low gravity, the construction of such towers on the moon would be easier than on Earth, where the tallest tower – the 830-metre Burj Khalifa in Dubai – took six years to build.
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