Outer Space Treaty

27 January 1967 · London, Moscow and Washington

Cold War & arms control

Background

The basic law of space. Countries may explore space freely but cannot place weapons of mass destruction in orbit or on celestial bodies, are responsible for their national space activities, and are liable for damage caused by their space objects.

Signed by

Opened for signature by the USA, UK and USSR

Why it matters

Bans nuclear weapons in space and says no country can claim the Moon or other celestial bodies.