The mission campaign for Arianespace’s fourth Soyuz flight from the Spaceport in French Guiana is entering a new phase as preparations begin for the integration of its Pleiades 1B satellite passenger on the launcher’s Fregat upper stage.
Pleiades 1B – a dual-use, very-high-resolution imaging satellite – has received its hydrazine propellant load in the Spaceport’s S5 payload preparation center, while the Fregat upper stage was fueled during separate operations performed several kilometers away in the S3B processing building.
All is now ready for the integration of Pleiades 1B atop the Fregat stage, followed by its encapsulation by the two-piece Soyuz payload fairing. This will occur in the S3B facility, using a multi-level integration stand.
Pleiades 1B will be orbited on a November 30 nighttime flight from the Spaceport’s ELS launch complex, marking the fourth Soyuz liftoff from French Guiana since this medium-lift vehicle’s service entry in October 2011 – and the second performed this year.
The 1-metric-ton-class Pleiades 1B spacecraft is designed to provide optical observation coverage with 50-centimeter resolution for the French and Spanish defense ministries, civil institutions, and private users. Operating from a 695-km. quasi-polar heliosynchronous orbit, it will accompany the twin Pleiades 1A spacecraft that was lofted by Arianespace last December on Soyuz’ second mission from the Spaceport.
The Astrium division of EADS built both Pleiades satellites for the French CNES space agency, which is prime contractor and system architect. They are based on smaller, less expensive and more agile platforms than their predecessors – the highly-successful Spot satellite series, which was launched by Arianespace beginning in 1986 on Ariane family launchers.
Arianespace Soyuz missions from the Spaceport use the autonomous, highly flexible Fregat upper stage, which is an 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 the Lavochkin Research and Production Association in Russia, this 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.
