Soyuz ST-B launches Galileo twins successfully to orbit

An Arianespace Soyuz ST-B rocket launched from the Kourou Spaceport in French Guiana on Friday, lofting two Galileo IOV (In-Orbit Validation) satellites – the early stages of what will eventually be a 30 satellite-strong European Naviation System constellation – to orbit. Lift-off was on schedule at 18:15pm UTC.

Soyuz ST-B Launch:

The Spaceport’s Soyuz launch site combines the proven design elements from the long-existing site at Baikonur Cosmodrome with satellite integration procedures that are in concert with the spacecraft processing used for Ariane missions.

Located 12 kilometers northwest from the existing Ariane 5 launch complex, the new Soyuz facility extends the Spaceport’s operational zone further up the French Guiana coastline.

The launch vehicle’s assembly building is 92 meters long, 41 meters wide, and 22 meters tall, allowing the vehicle to be assembles horizontally, prior to rolling out to the launch site, which is configured after the Russian Baikonur and Plesetsk Cosmodromes, albeit with a new mobile launch service tower.

The Soyuz’ transfer to the Spaceport’s launch zone is performed with the launcher riding horizontally atop a transporter/erector rail car.  Soyuz was then raised into position on the pad, and in contrast with the Baikonur Cosmodrome processing flow, is protected by a gantry that moves into place for payload integration.

The Soyuz-2-1 rocket is a descendent of the R-7 Semyorka, the world’s first intercontinental ballistic missile. The R-7 was designed by Sergei Korolev, and first flew in 1957. A modified version was used to launch the first satellite, Sputnik 1, on 4 October of that year.

The R-7 formed the basis for the Luna, Vostok, Voskhod, Molniya and Soyuz families of rockets, and to date all Soviet and Russian manned spaceflights have been launched using rockets derived from the R-7.

The Soyuz, which first flew in 1966, was a modification of the Voskhod rocket featuring an upgraded and lighter telemetry system, and more fuel efficient engines. It was initially used to launch only Soyuz spacecraft; however with the introduction of the Soyuz-U in 1973 it began to launch other satellites as well.

The Soyuz-U, which remains in service, is the most-flown orbital launch system ever developed, having made around 750 flights to date, plus around 90 more in the Soyuz-U2 configuration optimised to use synthetic propellant.

The Soyuz-2 was developed from the older Soyuz models, and features digital flight control systems and modernised engines. It first flew in 2004, and this is its twelfth launch.

Two variants are currently in service; the Soyuz-2-1a, and the Soyuz-2-1b which features an RD-0124 third stage engine which provides additional thrust.

The RD-0124 is a staged-combustion engine powered by a multi-stage turbopump, which is spun by gas from combustion of the main propellants in a gas generator. These oxygen-rich combustion gases are recovered to feed the four main combustion chambers where kerosene – coming from the regenerative cooling circuit – is injected.

This will be the first use of the RD-0124 since it’s involvement in the December, 2011 failure of Soyuz’s attempt to send the Meridian-5 satellite into orbit.

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.

A third configuration, the Soyuz-2-1v, is currently under development and is expected to make its maiden flight next year. It features an NK-33 engine in place of the RD-108A used on the core stages of the other configurations, and does not include the strapon boosters used by other configurations. Exclusive documentation on this vehicle was acquired by L2 (LINK).

The Soyuz-2 forms the basis for the Soyuz-ST rocket, which made its maiden flight from Kourou in French Guiana. The Soyuz-ST is optimised to fly from Kourou, and also incorporates a flight termination system and a modified telemetry system.

The launch of the Soyuz-ST (VS03) will carry two Galileo IOV satellites into orbit, FM3 and FM4. Weighing 700 kg. each, they will join the initial two IOV spacecraft orbited on Arianespace’s historic VS01 flight on October 21, 2011 – which marked Soyuz’ introduction at the Spaceport.

The mission is set to last just under 3 hours, 45 minutes. During this period, the Fregat upper stage will 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.

Galileo is a European initiative, with this navigation system being developed in a collaborative effort of the European Union and the European Space Agency.

The four satellites launched on Arianespace’s VS03 and VS01 missions will form an operational mini-constellation that enables a validation of the Galileo system. All four spacecraft were built by a consortium led by the Astrium division of EADS, with assembly and testing performed by Thales Alenia Space.

Once the four IOV satellites are in orbit, they will provide the minimum information needed for space-based navigation: latitude, longitude and altitude data, along with ranging accuracy; enabling assessment of the Galileo system’s performance, while also allowing suppliers to realistically check their receivers and services against actual signals.

Each satellite combines the best atomic clock ever flown for navigation – accurate to one second in three million years – with a powerful transmitter to broadcast precise navigation data worldwide.

Based on ESA research and development dating back to the early 1990s, two separate atomic clock technologies have been developed and qualified in Europe, then proved suitable for the harsh environment of space by the two GIOVE missions.

GIOVE-A launched on a Soyuz rocket from Baikonur Cosmodrome in Kazakhstan on 28 December, 2005, followed by GIOVE-B – again on a Soyuz rocket from Baikonur – on 27 April, 2008.

The full compliment of hardware includes two Passive Hydrogen Maser atomic clocks; two Rubidium atomic clocks; Clock monitoring and control unit; Navigation signal generator unit; L-band antenna for navigation signal transmission, C-band antenna for uplink signal detection, two S-band antennas for telemetry and telecommands and a search and rescue antenna.

Arianespace has been chosen to deploy the entire Galileo constellation of 30 satellites. This began with the launch of the first two experimental satellites, Giove-A and Giove-B, orbited by Arianespace’s Starsem affiliate on Soyuz launchers from Baikonur Cosmodrome in 2005 and 2007.

The remaining 24 Galileo constellation satellites will be orbited through 2015, using six additional Soyuz vehicles carrying two spacecraft each, along with three Ariane 5s configured with four per launch.

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