It was only a matter of time: with resources on Earth mostly claimed, and with technological costs constantly on the decline, private entrepreneurs are looking to harvest resources in outer space (here is just one example).

But is private enterprise legal outside of Earth’s orbit?  Can companies engage in the buying and selling of outer space resources?

Currently, the answer is probably no.

The law of outer space is governed by a series of treaties, the most important (and oldest) being the 1967 Outer Space Treaty.

Article I of the Outer Space Treaty declares outer space to be the “province of mankind”.

Article II declares, “Outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means.”

Article IX requires countries to conduct their exploration of outer space (including the Moon) “so as to avoid their harmful contamination”.

Under the language of this treaty, it would be difficult to argue that a private company had authority to conduct the same type of resource exploitation that gets done here on Earth.

“Province of mankind” and rejection of “national appropriation” suggests an outer space commons; and avoiding “harmful contamination” suggests a prohibition on the types of practices that led to the Gulf Oil Spill and the Fukushima Crisis.

Ninety-eight countries, including the United States, have ratified the Outer Space Treaty.  Under international law, ratification serves as a promise to other countries that the terms of the treaty will be honored.  And under national law, treaties are the “Supreme Law of the land.”

A much stronger treaty, the 1979 “Moon Treaty,” explicitly prohibits private property on the Moon.

Article 11 declares that the Moon and its natural resources are “the common heritage of mankind,” and that no part of the surface or subsurface of the moon shall “become the property of any State, international intergovernmental or non-governmental organization, national organization or non-governmental entity or of any natural person.”  The treaty requires an international regime for any exploitation of resources.

The Moon Treaty, however, has not been ratified by any Moon-faring nation, and likely lacks weight in international law.

The thing about any treaty, though, is that it is only as good as the promise to honor it.

Five hundred years ago, after Columbus landed in the West Indies, the Spanish didn’t think twice about sending more people over to see what they could find and conquer.

To avoid disputes, they signed the Treaty of Tordesillas and split up the world with the Portuguese, who went East instead.

The Treaty of Tordesillas has little weight today.

Should the US (or Russia, or China, or India) discover some dynamite resource on the Moon, international politics will have a much greater influence on how resources get treated then current legal language.

Today, there are a variety of countries with the technology and military might to challenge US space dominance.

In such a world, sharing may be the preferred outcome than conflict.

And of course, there is always the idea of leaving outer space alone until countries can figure out how to clean up some of the giant messes here on Earth.

Pushing the limits of technology can create grave problems, as people in the Gulf and Japan are realizing.

And technological feasibility doesn’t automatically make something a good idea.