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Raumfahrt - ESA startet Galileo-Satelliten mit Sojus-ST-B-Rakete

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The two Galileo satellites and their upper stage have been enclosed within their protective fairing, and moved to join the Soyuz rocket on the launch pad.
 
The halves of the fairing were sealed together around the satellites, their supporting dispenser and Fregat-MT upper stage on Friday, within the Upper Composite Integration Stand of building S3B of Europe’s Spaceport in French Guiana.
Yesterday, the Upper Composite was moved to the launch site, for vertical mating to its three-stage Soyuz ST-B rocket.
The 4.1 m-diameter fairing protects the satellites from the stresses of launch and flight through the bulk of the atmosphere. It will be ejected about three and a half minutes into the flight, when the upper stage reaches the top of the atmosphere.  
Fregat, modified to carry extra propellants, will fire for the first time about 10.5 minutes after launch, raising the satellites up to orbital velocity and their operating altitude of 23 222 km.
As it climbs, Fregat will spin slowly in ‘barbecue mode’, to keep the temperatures of the satellites even.
From launch to final deployment, when the dispenser releases the satellites sideways in opposite directions, will take three hours and 44 minutes.
The launch is scheduled for 18:15:00 GMT (20:15:00 CEST) on 12 October. 
Galileo taking shape
 
This follow-up launch marks a major step for Europe’s own satellite navigation system.
Four is the minimum number of satellites needed to achieve a navigational fix on the ground, with one satellite each to measure latitude, longitude, altitude and provide a time reference.
So once this second pair of satellites has been commissioned and tested, the quartet will form a completely operational mini-constellation that will be used to validate the Galileo system. 
 
 
The performance of the satellites in space together with the worldwide ground infrastructure serving to maintain Galileo’s service accuracy will be assessed in depth, to prepare the way for the launch of further satellites and then deliver initial services by mid-decade and finally build up to full operational capability.
These two new satellites are also the first to carry search and rescue antennas to pinpoint aircraft and ships in distress as part of the international Cospas–Sarsat system. 
Quelle: ESA
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Update: 10.10.2012 / 23.30 MESZ
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This photo series highlights the VS03 Soyuz’ rollout and final integration at the Spaceport. At left, the launcher emerges from the MIK assembly building for its transport to the launch zone. The Spaceport’s mobile gantry moves into place around Soyuz, which is held in position over the launch pad (image #2). In the third photo, the launcher’s payload fairing containing two Galileo satellites and the Fregat upper stage is ready for transfer to the launch zone, where it was raised to an upper level of the mobile gantry for integration atop Soyuz (image #4).
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Soyuz Flight VS03
Arianespace’s next medium-lift Soyuz is now fully assembled in the launch zone for its upcoming Spaceport mission, ready for the final steps leading to a Friday afternoon liftoff from French Guiana with two Galileo navigation satellites.
This flight is designated VS03 in Arianespace’s mission numbering system, and it will be the Spaceport’s third launch since Soyuz was introduced at this near-equatorial facility one year ago.
The VS03 Soyuz carries a second pair of Galileo In-Orbit Validation (IOV) satellites, which are to join the first two spacecraft orbited by Arianespace’s historic VS01 flight on October 21, 2011, marking Soyuz’ introduction at the Spaceport.   Once all four are operational in space, they will provide the minimum number of satellites required for navigational fixes – enabling system validation testing when all are visible in the sky.
For this latest Arianespace mission, the basic three-stage Soyuz vehicle was transferred yesterday from its MIK assembly facility to the ELS launch zone.  This process used the traditional horizontal rollout procedures employed in some 1,790 flights of the Russian-produced Soyuz family from Baikonur Cosmodrome in Kazakhstan and Plesetsk Cosmodrome in Russia.
In procedures that are specific to the Spaceport’s processing flow, Soyuz was transferred without its payload.  After the vehicle was raised vertically over the launch pad, a purpose-built 52-meter-tall mobile gantry moved into position around the Soyuz – providing a protected working environment for yesterday evening’s integration of the launcher’s payload fairing, which contains the two Galileo satellites as well as the Fregat upper stage.  This vertical procedure enables payloads to be installed as traditionally performed with Western launch systems – including the heavy-lift Ariane 5 and light-lift Vega members of Arianespace’s launcher family.
The VS03 launch is scheduled exactly at 3:15:01 p.m. local time in French Guiana on October 12, with the mission lasting just under 3 hours, 45 minutes.  During this period, the Fregat upper stage is to perform two propulsive burns – positioning the Galileo satellites for their deployment into a circular medium-Earth orbit of 23,222 km., inclined 55.345 deg.
As a European initiative, the Galileo satellite navigation system is being developed in a collaborative effort of the European Union and the European Space Agency.  The In-Orbit Validation (IOV) satellites weigh 700 kg. each and were built by a consortium led by the Astrium division of EADS – which produced the platforms and has responsibility for the payloads; while Thales Alenia Space handled the assembly and testing tasks. 
Total payload lift performance for the VS03 flight is 1,580 kg., which includes the two spacecraft, their dual-payload dispenser and other integration hardware.
The VS03 mission continues a busy year of activity for Arianespace, during which it already has performed five heavy-lift Ariane 5 flights from the Spaceport (orbiting eight telecommunications relay platforms and one Automated Transfer Vehicle for International Space Station servicing); along with a Soyuz mission from Baikonur Cosmodrome, conducted by the company’s Starsem division to loft a European weather satellite. 
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Quelle: arianespace
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