Galileo Full Operational Capability satellite on top of a measuring machine to check physical properties such as the satellite's centre of gravity, centre of mass, moment of inertia and product of inertia. This is a requirement for compatibility with Galileo’s two types of launch vehicle types – Soyuz and Ariane 5 – as well as helping with controlling their orientation in a fuel-efficient way, elongating their working lifetimes in orbit. The top side of the satellite is seen, with thrusters visible. On top can be seen the S-band telemetry, tracking and telecommand antenna (left) and the C-band antenna for navigation message corrections (right).