Fifty years ago, on 27 January 1967, the Outer Space Treaty was opened for signature. As a successful undertaking in international diplomacy, and one that helped foster the global development of outer space as a realm of humankind’s activities, the importance of this event warrants reflection.
Many experts in international law believe that the fundamental provisions of treaty are so well-observed and respected that they exist as an entirely different set of legal rules, outside of the textual treaty, as “customary” international law.
At signing ceremonies in Moscow, London, and Washington, 62 countries participated in the political act of signing the Outer Space Treaty. Its full title bears repeating: Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies. Rather than a treaty solely about space exploration and human spaceflight, the treaty was principally developed with international peace and security in mind. At the Washington signing event, President Lyndon B. Johnson spoke about the security and non-armament aspects of the treaty and how it would help lessen the threat of conflict.
The Outer Space Treaty entered into force as a binding legal instrument between signatory states on 10 October 1967. Fifty years later, 104 states of the international political order are now parties to the Outer Space Treaty. These include major space powers like the US, Russia, China, Japan, and the European members of the European Space Agency, as well as emerging space powers like Brazil and India. States that merely use or benefit from space technologies and capabilities have also signed the treaty in order to avail themselves of its rights. Many experts in international law believe that the fundamental provisions of treaty are so well-observed and respected that they exist as an entirely different set of legal rules, outside of the textual treaty, as “customary” international law. And, as customary international law, the Outer Space Treaty reflects rules that bind even those states who are not formal parties to the treaty itself.