Orbital Slots and Spectrum: Scarce Resources in Space

Why positions in geostationary orbit and radio frequencies are valuable, limited resources, and how they are shared among countries.

Satellites need two scarce resources: a place in orbit and radio frequencies to communicate with Earth. Both must be shared among countries and companies.

Geostationary slots

Satellites in geostationary orbit, about 36,000 kilometres above the equator, circle Earth at the same speed as it rotates, so they appear fixed in the sky. This makes them ideal for television and communications, since dishes can point at one spot. But satellites must be spaced apart to avoid interference, so the number of useful positions, or slots, is limited.

Radio spectrum

Satellites send and receive signals using radio spectrum. If two satellites use the same frequencies in overlapping areas, they interfere. Spectrum is therefore a scarce resource that must be coordinated.

The ITU

The International Telecommunication Union, a United Nations agency founded in 1865, coordinates the use of orbital slots and satellite frequencies. Countries file applications for orbital positions and frequencies, and the ITU records them to avoid interference. Rules have traditionally worked on a mostly first-come, first-served basis, with some slots reserved for countries to ensure fair access.

Equity concerns

Developing countries have argued that first-come allocation favours countries that launched satellites early. In 1976, several equatorial countries signed the Bogotá Declaration claiming rights over the geostationary orbit above their territory, though this was not accepted internationally. The ITU later planned some frequencies and slots to guarantee each country a share.

New pressures

Mega-constellations in low Earth orbit have increased demand for spectrum and raised questions about how to share it between satellite and ground networks, such as mobile phone services. Domestic governments also decide how to assign satellite spectrum to companies, as India did in 2025.

Paper satellites

Because slots and frequencies are valuable, some countries and companies have filed applications for more satellite networks than they planned to build, sometimes called "paper satellites", to reserve resources. This can block others. The ITU introduced rules requiring satellites to actually be launched within set deadlines to keep their filings.

Thinking space is unlimited, so no rules are needed

Useful orbits and radio frequencies are limited and can be congested. International coordination is essential to prevent interference and ensure fair access.

Key takeaways

Geostationary orbit slots and radio spectrum are scarce resources.
The ITU, founded in 1865, coordinates orbital slots and satellite frequencies.
First-come allocation raised equity concerns for developing countries.
Mega-constellations have increased pressure on spectrum.