Missile Technology Control Regime
A voluntary multilateral export-control arrangement (established 1987) that restricts the proliferation of missiles and the technology to build them, including many space launch and propulsion systems.
The MTCR is an informal, voluntary partnership among member states that coordinates national export licensing to limit the spread of unmanned delivery systems capable of carrying weapons of mass destruction.
Its Equipment, Software and Technology Annex divides controlled items into Category I (complete rocket and unmanned aerial vehicle systems and major subsystems, subject to a strong presumption of denial) and Category II (a broader range of components and technologies). Because launch vehicles and many propulsion technologies overlap with missile technology, space programmes routinely encounter MTCR-controlled items.
Membership is not a treaty; states implement the regime through their own national export-control laws.