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Return to the Moon
Dr Duncan L Copp
June 2008
Return to the moon | Written in the rocks | A grand observatory | Space resource | A manned return? | The driving force | Find out more
Space resource
It seems then that a return to the moon has considerable scientific merit, but could it be made economically viable? Does the moon hold any economic value? The answer is yes, though not in terms of modern-day economic mining – the moon isn't like the fictitious South American city El Dorado, abounding in gold. But from its crustal rocks and lunar soil, oxygen, hydrogen, iron, aluminium and some rare earth elements can be extracted and used to produce water and rocket fuel (hydrogen and oxygen).
Why would we want to go to the moon to make oxygen when our atmosphere teems with it? Dr Heather explains: 'Once a mining facility is established, it is cheaper to extract these elements from the moon and bring them to low Earth orbit than it is to launch them on a rocket from Earth.' This again is owing to the moon's weaker gravity – energy needed to move materials, weight for weight, is much less on the moon. 'The moon provides a ready supply of life-supporting substances that can be used both on the lunar surface and in space. If we are clever, we need ferry only a fraction of the materials needed to live and work in space, the rest already lies waiting for us in orbit on the moon.' Obviously a major economic advantage for space exploration.
Lunar soil also has its uses, as a crude building material. It can be utilised to make glass, ceramics and concrete, and these can be used to protect against the harsh lunar environment. A space pod or station buried beneath two metres of lunar soil would be protected from solar and cosmic radiation, in the same way that Earth is protected by its atmosphere and magnetic field.
But it's another lunar resource which may have substantial benefits for a planet faced with the very real threat of climate change. Harrison Schmitt, now Adjunct Professor at the Fusion Technology Institute (FTI) at the University of Wisconsin, and his colleagues are very excited by it. 'There is a very important and environmentally-friendly fuel on the moon called Helium-3 (3He) locked in the lunar soil. When fused with itself it can produce protons that can be converted directly to electricity,' says Schmitt. 'The reaction produces no radioactive waste in the process and is highly efficient. The moon is our principal resource for 3He.'
Schmitt estimates there are about 1 million tonnes of 3He on the moon, enough to power the world for thousands of years. Approximately 25 tonnes could supply the entire United States' energy needs for a year. A considerable amount of energy is required to mine 3He, (producing 70 tonnes of 3He requires heating a million tonnes of lunar soil to around 800oC). But there is a ready supply of solar power on the moon as there's no obscuring atmosphere and, because the moon rotates much more slowly than Earth, each moon 'day' is equivalent to 14 Earth days.
Next: A manned return? >
In the Shadow of the Moon >
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