The Fregat upper stage for Arianespace's upcoming Soyuz launch from French Guiana has been moved to the Spaceport's S3B facility, where it will be fueled and integrated with the mission's two Galileo navigation satellites. Fregat is an autonomous, highly flexible orbital vehicle that can be restarted up to 20 times in flight - enabling it to carry out a wide variety of complex mission profiles.

Built by Russia's Lavochkin Research and Production Association, the Fregat upper stage incorporates an array of six welded spherical tanks - with four spheres serving as the propellant tanks, while the other two operate as sealed instrumentation bays containing the flight control system, along with radio and telemetry systems.

The Fregat to be used on Arianespace's next Soyuz mission from the Spaceport underwent its initial checkout at the launch site's dedicated MIK vehicle assembly building for the Russian-built launcher, and was transferred by road this week to the S3B facility.

To support Arianespace's Soyuz launch activity in French Guiana, the S3B site has been configured for final preparation of Fregat upper stages, along with the mating of their payloads.

This is the fueling location for Fregat, and it contains the integration stand where satellite passengers are installed atop the upper stage, along with the payload fairing.

The upcoming Soyuz mission is set for the second half of 2012, carrying two more In-Orbit Validation (IOV) spacecraft for Europe's Galileo navigation satellite system. These two spacecraft are to join another pair of Galileo IOV satellites that were launched by Arianespace in October 2011 on Soyuz' maiden flight from French Guiana.

Having all four IOV spacecraft in orbit will enable the first computation of on-ground positioning based solely on Galileo satellites, marking a significant step in the European program.

This will be followed by deployment of additional satellites and ground segment elements to achieve the Full Operational Capability status, allowing Galileo navigation and positioning services to be provided for users.

The Galileo IOV spacecraft are produced in a European industry consortium led by the Astrium division of EADS and Thales Alenia Space.

Galileo is an initiative of the European Commission and European Space Agency, and is designed to create an independent global satellite navigation system for Europe - while also being interoperable with the U.S. GPS and Russian Glonass networks for enhanced combined performance.

Arianespace is responsible for deploying the entire Galileo constellation of 30 satellites, using a mix of both its medium-lift Soyuz and Ariane 5 heavy-lift launchers.