Arianespace Soyuz ST-B successfully launches four O3b satellites

by William Graham, Chris Bergin

An Arianespace Soyuz ST-B successfully lofted four O3b satellites from the Kourou Spaceport in French Guiana on Thursday – following launch at 18:55 GMT. This mission was part of the next installation of O3b Networks’ creation of a space-based constellation to deliver telecommunications and Internet services with the speed of a fiber-optic network.

Arianespace Soyuz Mission:

This latest mission, on the behalf of O3B Networks, followed on from last year’s Soyuz ST-B mission that lofted the first four satellites for this constellation.

ATKThis Soyuz mission was designated Flight VS08 in Arianespace’s launcher family numbering system.

As such, this was the eighth liftoff of the medium-lift workhorse from French Guiana since its 2011 introduction.

O3b’s Ka-band satellites were built by prime contractor Thales Alenia Space, and are to be positioned at a medium-orbit altitude of approximately 8,062 kilometers – offering high speed, low cost, low-latency Internet and telecommunications services to emerging markets.

O3B SatsThe spacecraft have a trapezoidal-shaped main body, which helped facilitate their integration on the payload system, which is a tube-shaped dispenser system, with the satellites mated to the upper and lower attach points.

Each bird had a liftoff mass of approximately 700 kg, designed to create a constellation of satellites providing telecommunications and Internet services over Asia, Africa, South America, Australia and the Middle East.

The four O3b-F2 satellites are designated as FM3, 6, 7 and 8. They were set to be launched in September of last year, ahead of a number of delays to their flow.

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

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

A third configuration, the Soyuz-2-1v, 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).

This vehicle was launched on its debut mission at the end of 2013.

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.

Soyuz’ Fregat upper stage – as was used on this mission- 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.

For this mission, the Fregat conducted three main burns during its orbital profile to deliver the four satellites. A quick fourth burn was conducted in-between the deployment of the satellites, which were released two at a time.

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.

New Soyuz PadLocated 12 kilometers northwest from the existing Ariane 5 launch complex, the 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 is 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.

Soyuz launching out of KourouArianespace had already conducted numerous Soyuz launches from French Guiana, beginning with the workhorse medium-lift vehicle’s historic inaugural Flight VS01 at the Spaceport in October 2011 – which orbited two Galileo IOV (In-Orbit Validation) navigation satellites for Europe.

It was followed by Flight VS02 inDecember 2011, carrying a mixed payload of France’s Pléiades 1A dual-use imaging platform, the Chilean SSOT observation satellite and four French ELISA micro-satellite demonstrators.

Flight VS03 was performed in October 2012 with two more Galileo IOV spacecraft, and Flight VS04 occurred in December 2012 to deploy the Pléiades 1B payload.

The fifth mission involved the launch of four O3B satellites last summer – followed by VS06 and VS07 flights, launching the Gaia space observatory and Sentinel-1A mission respectively.

(Images via Arianespace, O3b and L2.)

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