GSTB v2B

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

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General

Designation	32781 / 08020A
Launch date	26 Apr 2008
Country of origin	Europe
Mission	Navigation
Perigee/Apogee	23222 km
Inclination	56°
Period
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.

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End of life

Out of service	Aug 2012
Cause
Decay

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External resources

http://www.giove.esa.int/

http://www.esa.int/esaNA/index.html
sat-index articles

Technical data

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Specifications

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
Stabilization
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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