The replacement for the old Outer Space Treaty of 1967. The new treaty's key clauses and later protocols include:
Environmental Protection: The treaty prohibits certain industrial processes in Earth-Lunar (and Martian) space, including self-replicating von Neumann machines and large-scale antimatter production.
Homesteading: The treaty contains vague language granting property rights to nations or corporate entities engaged in economic development of particular areas, known as 'zones of common courtesy.'
Orbital Engineering: Altering the orbit of asteroids, comets, or moons is regulated, especially into Earth-Lunar and Martian space, and flight plans must be filed with international agencies.
Space Propulsion: The treaty prohibits Orion drives (which use external nuclear explosions for propulsion) and regulates the use of fission or antimatter drives within Earth's atmosphere or LEO.
Terraforming: The treaty bans new terraforming operations without international consensus.
Weapons in Space: Deployment of 'defensive' weapon systems in space is permitted, but weapons of mass destruction are prohibited.
Although the Revised Outer Space Treaty is broadly accepted as a good compromise, it remains just that; strengthening, altering, weakening, or abolishing it is a major objective of many rival interests. Black holes have fallen through a loophole in the OST, and negotiations on a protocol are in progress.