Ahead of Galileo satellites like this one going to space, they are switched on as if already operating there within ESA’s Maxwell EMC Facility. This test procedure is a check of the satellite’s ‘electromagnetic compatibility’, with all its systems running together to detect any harmful interference between them.

Once Maxwell's main door is sealed, its metal walls form a ‘Faraday Cage’, screening out external electromagnetic signals. The ‘anechoic’ foam pyramids covering its interior absorb internal signals – as well as sound – to prevent any reflection, mimicking the infinite void of space for satellite testing.

Seen here sheathed in multi-layer insulation, the 2.5m by 1.2 m by 1.1 m satellite’s main 1.4-m diameter antenna transmits L-band navigation signals down to Earth. To its left is the hexagonal search and rescue antenna that picks up distress signals and relays them to local emergency services, contributing to the saving of more than 2000 lives annually.

To the bottom right of the navigation antenna are a pair of infrared ‘Earth sensors’ whose task is to keep the navigation permanently locked onto Earth by homing in on the contrast between the heat of Earth’s atmosphere and the cold of deep space. Above them is the laser retro-reflector: lasers are shone up to this from the stations of the International Laser Ranging Service to perform an independent check of the satellite’s orbital position down to an accuracy of less than a centimetre, as a backup of standard radio ranging.

Above that is the circular C-band antenna which every 45 minutes or so receives the navigation messages from the Galileo ground segment. These signals incorporate corrections for slight clock errors, orbital drift or satellite malfunctions that user receivers can process as they perform positioning fixes, helping ensure Galileo remains the world’s most accurate satellite navigation system, delivering metre-scale positioning to users around the globe.

What resembles a white baton on the end of the satellite is its S-band antenna, employed to return ‘housekeeping’ telemetry data to mission control on Earth and pick up telecommands in turn to operate the satellite platform and payload – as well as performing the ranging used to estimate the satellite’s position in space.

The Maxwell EMC Facility is part of the ESTEC Test Centre in ESA’s technical heart in Noordwijk, the Netherlands – Europe’s largest satellite testing facility, which has flight-tested all but two of the 28 Galileo satellites already in orbit, and is currently doing the same for the next 10 satellites planned to join the constellation.

About Galileo

Galileo is currently the world’s most precise satellite navigation system, serving more than three billion users around the globe.

The Full Operational Capability phase of the Galileo programme is managed and funded by the European Union. The European Commission, ESA and EUSPA (the EU Agency for the Space Programme) have signed an agreement by which ESA acts as design authority and system development prime on behalf of the Commission and EUSPA as the exploitation and operation manager of Galileo/EGNOS. “Galileo” is registered as a trademark in the database of the European Union Intellectual Property Office (n° 002742237).