Galileo prototype GIOVE-A switched off after 16 years in orbit

Wed, 24 Nov 2021 04:00:00 GMT
ESA Navigation

Europe’s first prototype satellite for Galileo, GIOVE-A, has today been formally decommissioned...

Europe's first prototype satellite for Galileo, GIOVE-A, has today been formally decommissioned after 16 years of work in orbit.

"If not for GIOVE-A the 26 Galileo satellites in orbit today would not exist," comments Paul Verhoef, ESA's Director of Navigation.

"At the time there was a lot of uncertainty: would we make it or not?" recalls Javier Benedicto, Head of the Galileo Project Department in ESA "GIOVE-A transmitted its first Galileo signal-in-space on 12 January 2006, meaning that Europe was formally in the navigation business."

The mission also carried a prototype rubidium atomic clock - proving their functionality for the operational Galileo satellites that would follow - as well as a radiation instrument.

A second Galileo prototype, GIOVE-B, followed its predecessor in 2008, this mission hosting a prototype passive hydrogen maser - the second type of atomic clock that Galileo relies on - along with an enhanced payload able to transmit for the first time the GPS-Galileo common signal.

Once the first Galileo satellites were in orbit and working well, ESA ended use of GIOVE-A in 2012.

"Actually, the satellite itself is still operating well," explains Sarah Lawrence of SSTL. "The reason for ending the mission is software obsolescence in our control centre. The decommissioning procedure involved transitioning the satellite to Earth pointing mode, turning off the reaction wheels and setting the attitude and orbit control system to standby mode, before finally switching off the on-board computer and transmitter."

SSTL went on to provide navigation payloads for operational Galileo satellites.

Today there are 26 Galileo satellites in orbit and Galileo has become the world's most precise satnav system, delivering metre-scale accuracy to more than 2.3 billion users around the globe.

Galileo is currently the world's most precise satellite navigation system, serving more than two billion users around the globe.

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