Let me ask you this: 'Who controls land ownership on the moon?'

(Ping Zhu)

The law of outer space is governed primarily by the Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies. Commonly referred to as the 'Outer Space Treaty', the agreement was opened for signature in 1967 and entered into force that same year.

Article I of the Outer Space Treaty declares that the exploration and use of outer space shall be "the province of all mankind". [It] designates outer space and the bodies contained therein, including the Moon, as res communes, ie, the property of everyone. What this means in practice is that space is treated just like a commons on Earth. Anyone can make use of the commons, but no one has any property rights while they are in situ. Subsequent practice has established, however, that resources, once removed, become the property of the removing party.

The Agreement Governing the Activities of States on the Moon and Other Celestial Bodies (the 'Moon Treaty'), opened for signature in 1979 and entering into force in 1984, attempted, without great success, to redefine the nature of property rights for outer space. The Moon Treaty expressly prohibited any form of property rights for in situ outer space resources pending the creation of an international property rights regime. That regime has yet to be developed. Moreover, such a regime is unlikely ever to be created under the auspices of the Moon Treaty, given that the agreement has been ratified by (and thus only applies to) a tiny handful of states – none of which has significant, independent, space-faring capability.

While it is currently impossible for any entity to purchase or claim a fee simple interest in non-terrestrial property, there is, nonetheless, one small loophole that would entitle an entity to temporarily exercise rights similar to a property claim for a limited region on, for example, the Moon. The OST does permit a nation, and by extension one of its citizens, to exercise a zone of control around a landing site for safety purposes. Thus, as long as you were actually present, you could exercise effective control of the landing site and its immediate environs. You could prevent others from intruding and extract mineral resources for use at the site or even for sale. You might even be able to sell your lunar installation to a new occupant so that they, in turn, could make use of the local environment. That said, no official fee simple interest accrues as a result of your presence. As soon as you (or your successor) abandoned the site, it would be legally indistinguishable from any other portion of the Moon, ie, it would have the status of a commons.

Lawrence D Roberts, Space Law & Policy Academic

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