Every satellite depends on infrastructure on the ground. Satellite ground systems include the antennas that talk to spacecraft, the networks that connect them and the control centres that operate missions. This article explains the building blocks of satellite ground infrastructure and shows how the large agency networks are organised.
The building blocks of a satellite ground system
- Ground station antennas: dish antennas that track the satellite across the sky, send commands and receive telemetry and payload data.
- Ground network: several stations at different locations, connected to each other, so that a satellite can be contacted more often.
- Mission control centre: where the satellite is operated, contacts are planned and data is processed.
- Data links and processing: terrestrial connections and data centres that deliver the data to users.
Example: ESA's Estrack network
ESA's tracking station network, Estrack, is a global system of ground stations that links satellites in orbit with ESOC, the European Space Operations Centre in Darmstadt, Germany. According to ESA, the core Estrack network comprises six stations in six countries. The network was established in 1975, with a first 15 metre station at Villafranca del Castillo in Spain.
Example: NASA's Deep Space Network
NASA's Deep Space Network uses three complexes near Barstow in California, near Madrid in Spain and near Canberra in Australia. They are placed so that, as the Earth rotates, another site can pick up a distant spacecraft's signal before it sinks below the horizon at the previous one. According to NASA, each site has one 70 metre antenna, one 26 metre antenna and several 34 metre antennas. In April 2024, all six antennas at the Madrid complex received data from Voyager 1 at the same time, a technique called arraying that combines the receiving power of several antennas, as shown on the cover image.
Commercial ground station networks
Most commercial operators do not build their own global network. They book antenna time from providers such as KSAT, SSC or AWS Ground Station. This ground station as a service model lets small teams operate satellites without owning antennas.
Planning the ground segment
- The orbit decides how often a satellite passes over each station. Polar and sun-synchronous satellites benefit from stations at high latitudes.
- Antenna size and frequency band must match the satellite's data volume and its frequency licences.
- Ground and space segment should be planned together, well before launch.
More basics are covered in our guide to ground stations and the ground segment.
Sources
- ESA: Estrack, ESA's global ground station network
- NASA: Deep Space Network
- KSAT: About us
- SSC: Ground Station Services
- AWS: What is AWS Ground Station?
Cover image: All six antennas of the Madrid Deep Space Communication Complex arrayed to receive data from Voyager 1, April 2024. Credit: NASA/JPL-Caltech, MDSCC/INTA, Francisco Moreno (PIA26147).