Outer Space Treaty - History in Perspective
Treaty forbids countries, not individuals from property claims in space
The Outer Space Treaty of 1967, signed by a majority of the nations of Earth, is the primary governing instrument concerning Space Law. Article 2 states that Outer Space shall not be subject to national appropriation, thus forbidding nations from extending their borders outside of Earth. This does not, however rule out the possibility of a private citizen executing a property claim in Outer Space.
During the space race, it became evident that the two major
players, the USA and the Soviet Union, might very well take the
imminent threat of nuclear war on Earth into the realm of Outer
Space. The Outer Space Treaty, forged in 1967 through the United
Nations, is perhaps the most important nonproliferation treaty
in existence, primarily aimed at preventing the weaponization of
space.
At the time, there was a high cause for concern that one of the two countries racing towards the Moon
would attempt
to annex it in the name of nationalistic pride. 
In the infancy of space exploration, rules and regulations concerning private citizens were left open for determination by future generations. This was no accident, no loophole, the silence of the Outer Space Treaty on private property rights was very intentional.
Put yourself in the shoes of the framers of the treaty – you have two nuclear superpowers are at the table to agree on how not to their conquests in space destroy the Earth. The mere mention of private property rights-the most deep rooted idealogical disagreement between the United States and Soviet Union – would have been counter-productive to the treaty making process, to say the least.
No provision whatsoever was made to forbid or provide for the sovereign rights of private citizens outside of Earth. With the Outer Space Treaty of 1967, the UN accomplished exactly what it was founded to do - prevent war. No judge, jury, congressional act or presidential decree on the can 'grant' or 'deny' ownership of deep space resources, since territorial jurisdiction by nations was explicitly forbidden by Article II. Article II effectively forbids countries from annexation of territory in Outer Space.
Jurisdiction of nations are forever confined to Earth's surface, and interstellar space is not the venue for territorial conquest in the name of the nation-state. Outer Space regulations are expressed through international treaties, negotiated on mankind's behalf, under the auspices of the United Nations Committee on Peaceful Uses of Outer Space. Nations and international governmental organizations party to the Outer Space Treaty are responsible for reflection of its principles through ratification into domestic law in a manner consistent with one another.
There is nothing in Article II, or anywhere else in the aforementioned treaty prohibiting exercise of territorial sovereign rights by private individuals/natural persons in Outer Space. Unlike similar international instruments relating to territorial sovereignty outside national jurisdiction, any attempt at exclusion of off-planet property claims for 'natural persons' is completely absent from the treaty.
Nevertheless, actions on the international level over the past 50 years have made necessary a formal confirmation of the legality of private property claims in Outer Space under the current legal framework, in order to settle the 50 year old argument on the subject.