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Galileo System Test Bed, also called Giove B (Galileo In Orbit Validation Element)


Designation 32781 / 08020A
Launch date 26 Apr 2008
Country of origin Europe
Mission Navigation
Perigee/Apogee 23222 km
Inclination 56°
Launch vehicle Soyuz #885

To demonstrate the Passive Hydrogen Maser (PHM), which should be the most accurate atomic clock ever launched into orbit (stability better than 1 nanosecond per day). Two PHMs will be used as primary clocks onboard the operational Galileo satellites, with two rubidium clocks serving as backups.

Worth EUR 72.3 million.

Had some problems shortly after launch with the fourth reaction wheel. Was promptly fixed. Went into safe mode on 9 Sep 2008 following a surge of radiation.

The signals produced by the satellite in operational mode are satisfactory for production stage.

End of life

Out of service Aug 2012

External resources


sat-index articles

Technical data


Prime contractor Astrium
Platform Proteus
Mass at launch 523 kg
Mass in orbit  
Dimension 0.95 x 0.95 x 2.4 m
Solar array 2 x 4.34 m
DC power 1100 W
Design lifetime 3 years

The payload is based on payload equipment supplied directly by ESA.

It incorporates a radiation-monitoring payload to characterise the space environment at the altitude of the Galileo constellation, as well as a laser retroreflector for high-accuracy laser ranging.

Downlinks 3 signals in L-band.

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