I love the language in the United Nations Treaties and Principles on Outer Space (related General Assembly resolutions and other documents) (PDF).
Here’s Article Number 1:
The exploration and use of outer space, including the Moon and other celestial bodies, shall be carried out for the benefit and in the interests of all countries, irrespective of their degree of economic or scientific development, and shall be the province of all mankind.
Outer space, including the Moon and other celestial bodies, shall be free for exploration and use by all States without discrimination of any kind, on a basis of equality and in accordance with international law, and there shall be free access to all areas of celestial bodies.
There shall be freedom of scientific investigation in outer space, including the Moon and other celestial bodies, and States shall facilitate and encourage international cooperation in such investigation.
The rest is in this embedded document:
You can find the Treaties and other space-related documents and databases, including the Online Index of Objects Launched into Outer Space, on the United Nations Office for Outer Space Affairs website.