Nature: The European Space Agency (ESA) will begin testing the Galileo navigation system on 20 October with the launch of two navigation satellites. Galileo will eventually consist of 27 operational and 3 spare satellites in three orbital planes and will broadcast on a wider range of frequencies than either the US GPS system or the Russian GLONASS system. It’s anticipated that Galileo will augment information from the other two systems, with its wider bandwidth providing more accurate measurements of Earth’s surface features. ESA anticipates that enough satellites will be in orbit to provide some services by 2015, with the full constellation in orbit by the end of the decade.