Understanding COPUOS
How COPUOS is structured
The full committee meets once a year in Vienna, but its detailed work is done in two standing subcommittees that also meet annually. Every decision is taken by consensus — no votes are held — which makes agreements durable but slow, and explains why much of the committee's recent output is voluntary guidance rather than binding law.
| Body | What it handles |
|---|---|
| Scientific and Technical Subcommittee (STSC) | Space debris, near-Earth objects, nuclear power sources, space weather, and the use of satellite data |
| Legal Subcommittee (LSC) | Status of the space treaties, national space legislation, registration of objects, and space-resource activities |
| Full Committee (plenary) | Reviews the subcommittees' reports and forwards recommendations to the UN General Assembly |
The five UN space treaties
Every one of the United Nations' five space treaties was negotiated in the COPUOS Legal Subcommittee before the General Assembly adopted it. See our entries on the Liability Convention and Registration Convention for detail on how responsibility and record-keeping work in practice.
| Treaty | Year | Core principle |
|---|---|---|
| Outer Space Treaty | 1967 | Space is free for all to use, cannot be claimed by any state, and must be used peacefully |
| Rescue Agreement | 1968 | States must assist astronauts in distress and return recovered space objects |
| Liability Convention | 1972 | A launching state is liable for damage caused by its space objects |
| Registration Convention | 1975 | Launching states must record their objects in a UN index |
| Moon Agreement | 1979 | The Moon and its resources are the "common heritage" of humankind |
Debris, sustainability and the limits of soft law
Since the treaty era ended in 1979, COPUOS has shifted to voluntary "soft law". Its 2007 Space Debris Mitigation Guidelines and 2019 Long-Term Sustainability (LTS) Guidelines — 21 measures agreed after nearly a decade of negotiation — ask operators to limit debris, passivate spent hardware and remove satellites from useful orbits at end of life. They matter because the tracked population of space debris keeps climbing, raising the risk of Kessler syndrome, a runaway collision cascade. Because these guidelines are non-binding and consensus-bound, some spacefaring nations have also pursued faster, like-minded frameworks such as the Artemis Accords outside the committee.
COPUOS versus the ITU
Two UN bodies share responsibility for space and are easy to confuse. COPUOS handles the law, policy and coordination of activities in outer space. The International Telecommunication Union (ITU) is separate: it allocates the radio spectrum and geostationary orbital slots that satellites need to operate without interfering with one another. In short, COPUOS governs conduct in space; the ITU governs the airwaves and orbital positions used from it.