The Fregat upper stage for Arianespace's third Soyuz mission from French Guiana is now undergoing pre-launch verifications in preparation for a flight in the second half of 2012 that will carry another two spacecraft for Europe's Galileo satellite navigation constellation.

After being moved into the Spaceport's Soyuz Launcher Integration Building - known by its Russian "MIK" designation - the Fregat was installed in a dedicated checkout station.

Soyuz' Fregat upper stage is an autonomous, highly flexible orbital vehicle built by the Lavochkin Research and Production Association. It can be restarted up to 20 times in flight - enabling the system to carry out complex mission profiles.

Fregat has an array of six welded spherical tanks, with four spheres serving as the propellant reservoirs, while the other two operate as sealed instrumentation bays containing the flight control system, along with radio and telemetry systems.

The three-stage Soyuz vehicle that ultimately will be integrated with this Fregat for Arianespace's upcoming mission also is at the Spaceport, having undergone regular maintenance checks earlier this year that are standard for the Russian-built vehicles that have been in storage prior to their missions.

This Soyuz is to carry Europe's next two Galileo In-Orbit Validation (IOV) satellites, joining the first pair of spacecraft lofted on Arianespace's initial flight of the Russian-built launcher from French Guiana in 2011.

The upcoming mission is designated VS03 in the numbering system for Arianespace's launcher family operated from the Spaceport - which is composed of the medium-lift Soyuz, heavy-lift Ariane 5 and light-lift Vega. The "V" represents the French word for "flight" (Vol), while "S" signifies the use of a Soyuz launch vehicle and its "3" denotes the third Arianespace mission of Soyuz from French Guiana.

Soyuz was first used from the Spaceport for its history-making maiden flight on October 21, 2011, which orbited the first two Gailieo IOV spacecraft, followed by a December 17, 2011 mission that lofted the French Pleiades 1 and Chilean SSOT satellites for civilian and defense image gathering, along with four French ELISA micro-satellite demonstrators for defense-related electronic intelligence gathering (ELINT).