Treaty guide

Outer Space Treaty Article II

The non-appropriation principle and its practical governance questions.

What it is

Article II provides that outer space, including the Moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, use, occupation, or any other means.

Why it matters

Modern missions raise questions about how to distinguish lawful use, safety control, resource support, and impermissible appropriation.

CGI work

OSTGAP studies Article II as one of the core treaty provisions where domestic implementation and operational practice need careful analysis.