The moon is the province of all mankind, and activities on the moon are subject to international law. We have a legal framework that governs outer space that applies to State parties to the space treaties. There are actually five space treaties.
The main one was signed in 1967 and is considered the Magna Carta of outer space. It’s called the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, Including the Moon and Other Celestial Bodies, and is commonly referred to as the Outer Space Treaty or OST. The treaty has been ratified by 104 jurisdictions and signed by a further 25. While signing is not as strong as ratification, it’s an acknowledgement that those countries signing also agree with governing principles.
"If you want to do something on the moon as a UK national then the UK is ultimately responsible for your actions."
Although not every country in the world has ratified The Outer Space Treaty, parts of it are still accepted as globally binding. It’s what the legal community would refer to as customary international law and states adhere to the regulations out of a sense of legal obligation or opinio juris.
However, even though the OST allows for private space actors, at the end of the day it’s all about countries being responsible for the actions of their nationals. If you want to do something on the moon as a UK national then the UK is ultimately responsible for your actions – which is why it is so important that so many countries have signed up to the treaty.
https://www.youtube.com/embed/na7vlnK_XT4?wmode=opaque
So what can’t you do? There are three main things. You can’t do anything that exploits or contaminates the moon, you cannot colonise it or appropriate it and you cannot carry out any military action or testing of weapons. The OST states that it’s forbidden to install weapons of mass destruction on the moon or to station them in outer space. The building of military bases or fortifications and military manoeuvres are also prohibited on the moon.
However, states are allowed to use military personnel for scientific research or peaceful purposes and countries can explore the moon and carry out scientific investigations, providing those explorations are for the benefit and in the interests of all countries.
"Any building or development on the moon must rely on cooperation and mutual assistance between nations."
So one country could build a space station, put vehicles on the moon, erect military buildings or fortifications on the moon, providing these activities are all for peaceful purposes and are for the use and benefit of all countries – any building or development on the moon must rely on cooperation and mutual assistance between nations.
Many people think that you can’t carry out commercial activities in outer space but this isn’t true – telecommunication satellites, for example, make huge sums of money but they don’t appropriate any areas of outer space, or damage it. A satellite company may have the right to use a certain slot in space, but they don’t own it.
https://www.youtube.com/embed/eAAc6iDS01U?wmode=opaque
There is currently huge momentum in space law with international agencies looking towards further cooperation – in the future we could see a moon village which would be multi-user and multi use, built as a collaborative effort between nations to help learn more about the moon and further scientific research within the international community.