The twin Galileo satellites were glimpsed for the very last time by human eyes yesterday as they were enclosed within their upper stage Soyuz launch fairing in preparation for their 20 October launch.
The previous week saw the pair of Galileo In-Orbit Validation satellites attached to their supporting dispenser. On Monday, the combined satellites plus dispenser were mated to the Fregat-MT upper stage that will transport them into their final 23 222 km orbit.
The mating complete, the halves of the Soyuz fairing were closed around the stack on Wednesday to form the ‘Upper Composite’.
The Galileo launch team watched intently as Russian technicians completed the encapsulation.
The satellites are now out of sight but hardly out of mind: they are monitored continuously via the data and power umbilicals that connect them to the outside world.
Two days before launch they will be subjected to a full launch dress rehearsal along with their Fregat.
On Friday the Upper Composite is due to be moved from the Upper Composite Integration Stand of building S3B to the Soyuz launch site, where it will be mated vertically to its three-stage Soyuz ST-B rocket, using the mobile tower.
Soyuz from French Guiana
This month’s launch will be historic: the first Soyuz launch from a spaceport outside Baikonur in Kazakhstan or Plesetsk in Russia.
As a medium-class vehicle, Soyuz will complement Ariane and Vega to extend the flexibility and competitiveness of Europe’s launcher family.
These first two Galileo satellites will be followed next year by two more. This quartet, built by a consortium led by EADS Astrium Germany, will form the operational nucleus of the full Galileo satnav constellation.
They combine the best atomic clock ever flown for navigation – accurate to one second in three million years – with a powerful transmitter to broadcast precise navigation signals.