bild

Galileo satellite network, illustration. The European Space Agency's Galileo navigation system will consist of 30 satellites orbiting over 23, 000 kilometres above the Earth. Galileo satellites are placed along three orbital planes so that a minimum of four satellites will be visible to receivers at any point on Earth once the constellation is complete. The Galileo network is scheduled for completion in 2020.(KEYSTONE/SCIENCE PHOTO LIBRARY SPL/P. Carril/EUROPEAN SPACE AGENCY/SCIENCE PHOTO LIBRARY)