Lunar habitation may be possible underground

A number of countries are preparing to send astronauts to the Moon.

It is likely, this time the missions won't just be flying visits but part of the work towards establishing a permanent presence of men and women on the Moon.

There are many motivations driving this. First of all, the Moon will be an excellent jumping off point for exploration of the Solar System and maybe beyond. In current space missions, the biggest obstacle is our practice of launching spacecraft from the Earth's surface. Those huge first stages and solid boosters are needed just to lift the spacecraft against the Earth's gravity and out of the atmosphere.

Launching a spacecraft from the Moon's surface means fighting a gravitational field about a sixth the strength of the Earth's. In addition, there is no need to climb above the densest part of the atmosphere before acceleration to interplanetary speeds. With almost no atmosphere to fight through, there would be no need to streamline the spacecraft. As in the case of the Apollo lunar landers, they can be configured uncompromisingly to carry out the tasks they are required to do.

The advent of tens of thousands of satellites in Earth’s orbit, providing global Internet and other services, is making life hard for ground-based radio astronomy. That makes the far side of the Moon a good place for high-sensitivity radio astronomy. The radio cacophony radiated by our planet would be blocked out. Astronomy at other wavelengths would benefit too, with no atmospheric blockage, no cloudy weather and the ability to see the stars even during the lunar day.

Using the Moon as a “Grand Central Terminal” providing connections to the rest of the Solar System and beyond and the operation of major science facilities will require a base providing long-term homes for lots of people. However, the advantages of the Moon for astronomy and space exploration will be partially lost if all the bits for spacecraft or telescopes need to be hefted up from the Earth's surface.

It would be better to source them locally. At least some of them can be mined from the lunar crust. With copious solar energy available during every lunar day materials can be mined, refined and made into much of what is needed. For many processes, the almost vacuum of the lunar atmosphere will help.

So how can we live on the Moon, with its extremes of temperature, high solar radiation, unblocked by any atmosphere, and the ever-present vacuum? The most likely option is underground. A few metres below the lunar surface, the temperature is constant and the solar radiation is blocked out.

In the past, thinking was that we would have to dig the holes from scratch, but recent discoveries offer a much easier option, lunar lava tubes.

In Hawaii and other places, there are underground hollow tubes where lava once flowed. Today they are dark, cool, and in the case of the Hawaii tubes, wet. However, a look at the walls of the tubes show they once contained flowing molten rock.

There are places on the Moon where round holes give us views into great, underground lava tubes. These look big enough to accommodate a huge base. It could be that large lengths of tunnel could be sealed off and pressurized, although, to start with, home for the astronauts is more likely to be a pressurized habitat imported from Earth and installed in one of those lava tubes.

The resource that would make colonizing the Moon easier is the local availability of water. In addition to providing something to drink, cook and wash with, it can be used to make oxygen to breathe and to make rocket fuel. There are science fiction stories where lunar colonies became hugely rich by providing the gateway for space exploration. The next decade or two will be interesting.

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• Venus is very low in the sunset glow, and getting hard to find.

• Around midnight Saturn lies low in the south, with Jupiter and Mars high in the southeast.

• The Moon will reach its last quarter on Oct. 24.

This article is written by or on behalf of an outsourced columnist and does not necessarily reflect the views of Castanet.