France: With the initial satellites of the Galileo constellation working well in orbit, ESA decided to end the mission of its pioneering GIOVE-A navigation satellite. Launched on 28 December 2005, this first experimental satellite performed the vital task of securing the radio frequencies provisionally set aside for Galileo by the International Telecommunications Union.
ESA formally ended GIOVE-A’s mission at the end of June, although it will go on being operated for now by prime contractor Surrey Satellite Technology Ltd of Guildford, UK, to gather radiation data and performance results from a GPS receiver.
“GIOVE-A had a design life of only 27 months, so to continue operating for 78 months is impressive,” said Valter Alpe, managing GIOVE activities for ESA.
“In August 2009, the satellite was moved into a graveyard orbit around 100 km above its normal 23 222 km to make way for the Galileo validation satellites.
“The first two of these were launched on 21 October 2011 and are performing well, so while GIOVE-A has served ESA well it no longer has a job to do.”
Built to a tight deadline by SSTL, GIOVE-A carries a rubidium atomic clock accurate to three seconds in a million years.
On 27 April 2008 it was joined by GIOVE-B, built by an Astrium-led consortium, which carries an even more accurate passive hydrogen maser clock – the first to be flown in space for navigation, accurate to one second in three million years – as well as a second rubidium clock. Operational Galileo satellites carry two pairs of both kinds of clock, for redundancy.