One option to avoid the high thermal variations is to bury any base buildings within the lunar regolith. This powdery material that covers the Moon’s surface has a low thermal conductivity and a high resistance to solar radiation. This means that it possesses strong thermal insulator qualities, and the deeper the colony the greater the thermal protection. Also, as a base will be heated, and heat transfer is very low on the Moon due to the lack of atmosphere, this can reduce thermal stresses further.

However, while burying a colony is an accepted idea, doing it in practice may be an enormous challenge. “I have not yet seen a design which can already handle this,” says Volker. “I assume it would be robotic ‘construction’ machines, which could be operated remotely.”

Crash or cover?

Another method by which this could be achieved is through the landing itself. Penetrators that pierce the surface on impact have already been suggested (on a much smaller scale) for several Moon missions, such as Japan’s Lunar-A and the UK Space Agency’s MoonLite proposal (now shelved, although the idea of a penetrator landing was so compelling that Esa have given it further consideration as a high-speed delivery mechanism for sampling and analysing the surface and subsurface of a planet or moon). The advantage of this concept is that the base is buried at impact, meaning it would only be exposed to relatively moderate thermal conditions before it is protected.

However, there would still be the problem of power supply, since a typical penetrator design offers only very limited options for using solar power. There are also the problems of the high-acceleration loads at impact and the pinpoint accuracy required for guidance control. “The impact force necessary for burying a structure would be extremely difficult to reconcile with necessary features of a manned base,” says Trollope.