A Galileo Full Operational Capability satellite inside the Maxwell test chamber of ESA's Test Centre in the Netherlands. Note its search and rescue antenna, left, and main navigation antenna, covered in silver 'single layer insulation' as it will be in space. Two further S-band telemetry, tracking and telecommand antennas are seen jutting out of the satellite body to its left and right sides. These 9 m-high spike-lined walls enclose the hushed interior of the chamber, isolating the satellite from all external influences to assess its electromagnetic compatibility. Once its main door is sealed, the metal walls of the chamber 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. The satellite’s systems are then switched on to detect any harmful interference as its various elements operate together.