What Are Orbital Slots?

The term ‘Orbital Slots’ refers to specific locations in the geostationary orbit (GSO) of a planet, where a satellite can be placed for communication purposes. The GSO is a circular orbit around the Earth at an altitude of approximately 36,000 km. In this article, we will discuss in detail what orbital slots are and their significance in satellite communications.

What is an Orbital Slot?

An orbital slot is a specific position in the GSO where a satellite can be placed to provide communication services to a particular region. The position of each slot is defined by latitude and longitude coordinates, which can be measured using sophisticated tracking equipment on the ground.

Why are Orbital Slots Important?

Orbital slots are essential for satellite communications because they allow satellites to provide coverage to specific regions on the Earth’s surface. Each orbital slot has its own unique coverage area, which is determined by the satellite’s beam width and power output.

For example, a satellite placed at an orbital slot over North America would provide coverage to all of North America and parts of South America. However, it would not be able to provide coverage to Europe or Asia because its beam width and power output would not be sufficient to reach those regions.

How are Orbital Slots Regulated?

The International Telecommunication Union (ITU) regulates the use of orbital slots through its Radio Regulations. These regulations ensure that there is no interference between satellites operating in adjacent slots.

Satellite operators must apply for permission from their respective national governments to use a particular orbital slot. Once permission has been granted, they must then coordinate with other satellite operators who are using adjacent slots to ensure that there is no interference between their satellites.

How Many Orbital Slots are There?

There are only a limited number of orbital slots available in the GSO due to limited spectrum availability and physical space constraints. The ITU currently allocates 1,492 orbital slots in the GSO, with each slot having a width of 0.05 degrees of longitude.

What Happens if an Orbital Slot is not Used?

If a satellite operator fails to use an assigned orbital slot within a specified period, usually three years, the ITU may revoke the assignment and make it available for other satellite operators to use. This ensures that valuable resources are not wasted and that the limited number of available slots are used efficiently.

Conclusion

In summary, orbital slots are specific positions in the GSO where satellites can be placed to provide communication services to specific regions on the Earth’s surface. They are regulated by the ITU to ensure that there is no interference between adjacent satellites and that they are used efficiently.

Understanding orbital slots is essential for anyone involved in satellite communications, as it allows them to select the best location for their satellites and ensure optimal coverage for their customers.