The idea of a base on the Moon is a staple of science fiction. After all, since it’s so close, it’s obviously the place to start. But is it so obvious? The book I’m reading for research, Entering Space by Robert Zubrin, has disabused me of that idea. Here is the thinking behind the Moon base:
The possible discovery of water on the Moon gives new life to an idea that has been discussed in both science fiction and the astronautical engineering literature for some time—that of using a lunar base as a staging point for missions to worlds beyond. The idea is that since the Moon has only one-sixth Earth’s gravity and no atmosphere, it’s possible to reach any destination in space much easier from the Moon than it is from the Earth’s surface. Thus, if indeed rocket propellant can be made available on the lunar surface, the Moon could well turn into an excellent refuelling station and port of call for interplanetary traffic.
Zubrin then goes on to explain how fuel would be created on the Moon from local rocks, but it is not an easy procedure. It could be used for fuelling spaceships for their return to Earth or for hopping around the Moon, but not for further travel. Because the spacecraft, its equipment, and most of its provisions would have to come from Earth, it actually takes more fuel to get to the Moon than to Mars. (He does explain the detail but I didn’t take it in.)
So if we can’t make money from the Moon’s resources or viably colonise it, why should we go? For science.
The Moon is the perfect place for astronomical observatories. It has no obscuring atmosphere and only rotates once every 28 days, so a telescope there can gather much more light from distant stars. It is also seismically dead and so provides a rock-steady platform. The development of telescope arrays enable much more detail to be recorded, but relies on knowing the distance between the telescopes in the array down to a millionth of a metre, something not possible on seismically-vibrating Earth or in free-floating space.
Optical astronomy would not be the only branch of humanity’s oldest science to benefit from a lunar base. The Moon’s lack of atmosphere makes it an ideal platform for conducting cosmic-ray, gamma-ray, x-ray, and ultraviolet astronomy. These techniques, which are difficult to impossible to perform through Earth’s thick atmosphere, are key to examining high-energy processes in the universe. The low temperatures available in the Moon’s permanently shadowed craters make them ideal locations for stationing infrared telescopes. The Moon’s far side is the only place in the solar system that is shielded from terrestrial civilisation’s massive radio chatter, and so is the best place for positioning radio telescopes. In addition, because the Moon has no ionosphere, a radio telescope positioned on the surface of the Moon can pick up low frequency (30 MHz or less) radio waves from space that the Earth’s ionosphere completely masks from reception by ground-based instruments here. Each of these windows in the electromagnetic spectrum offers unique advantages and opportunities to discover physical phenomena, and all of them can best be studied from the Moon.
As Zubrin later remarks: What the Moon lacks in amenities, it makes up for with the view.
The last thing considered, is building a beanstalk. What?
Since 1960 there have been various proposals for building some sort of elevator to lift thing from Earth into orbit. Generally known as a beanstalk, the theory is great, but in practice it’s impossible, because gravity would necessitate the tether being millions of tons in weight. However, on the Moon the gravity if one-sixth that of Earth, so it might just be possible.
To misuse a famous saying: Watch that space.
