21 Oct 2011

First Galileo Operational Sat Nav Satellites Launched

The first two satellites in the European Galileo Sat-Nav system were successfully launched.

After difficulties the previous day delayed the launch, these were successfully resolved and the Russian Soyuz rocket was able to lift off from its new base in French Guiana at 07:30 local time (10:30 GMT; 11:30 BST).

The European Space Agency, ESA, launched two satellites, GIOVE-A and -B, in 2005 and 2008 respectively, as a precursor to the operational satellites. These initial two satellites were intended to reserve the radio frequencies for Galileo set aside by the International Telecommunications Union and to enable testing of the key Galileo technologies.

The two satellites launched on 21st October 2011 are the first two of four operational satellites being launched in 2011 and 2012. Their aim is to validate the Galileo concept in both space and on Earth. Once this In-Orbit Validation, IOV phase has been completed, additional satellites will be launched to reach Initial Operational Capability, IOC around 2015.

Galileo is the European version of the very popular America GPS – Global Positioning System or Navstar. Europe is investing billions of Euros in the system which it anticipates will bring significant return to EU member nations in the form of new businesses that can exploit precise space-borne timing and location data.

Although the launch has been successful, the overall mission to install the satellites in their orbit at an altitude of around 23 000 km will take many hours. The satellites first have to be installed in a low orbit, and then “catapulted” into an elliptical orbit that will take them to their final altitude, and then establish them in this orbit.

The Galileo system carries more accurate clocks than the American GPS, and should therefore be more accurate – figures of accuracy to 1 metre are expected, against GPS which gives accuracy levels of around 10 metres. The plan is to the systems interoperable, providing a considerably better service with greater accuracy, reliability and faster fixes.

However, this improvement will not be seen for some while. The testing must be completed and further satellites launched before the system is expected to be switched on around 2015.

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