Soyuz ST-B launches with four O3b satellites
An Arianespace Soyuz ST-B rocket successfully launched four O3B satellites from the Kourou Spaceport in French Guiana on Tuesday. The launch – the second Soyuz to lift-off in close succession – was scheduled for 18:54 UTC. However, due to a red hold, the teams opted for a launch 33 minutes later.
Soyuz ST-B Launch:
The mission is utilizing a Soyuz-STB/Fregat-MT, a Soyuz-2-1b optimized for commercial launches from the Centre Spatial Guyanais in French Guiana, with a Fregat upper stage.
The payload is the first four communications satellites for O3b. These will be the first satellites of Jersey, a small island in the English Channel which is a British Crown Dependency, but is not part of the United Kingdom.
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 8,060 kilometers – offering high speed, low cost, low-latency Internet and telecommunications services to emerging markets.
The 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.
In addition to the first batch of spacecraft lofted by the upcoming Soyuz mission in June, another Arianespace flight is scheduled to orbit four more later this year, followed by an additional set of four in 2014.
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 optimized to fly from Kourou, and also incorporates a flight termination system and a modified telemetry system.
Designated VS05 in Arianespace’s launcher family numbering system – this mission involves a flight duration of 2 hours and 22 minutes.
After the powered phases for the Soyuz ST-B vehicle’s first three stages, the Fregat-MT upper stage performed four burns, allowing deployment of the O3b spacecraft.
The Soyuz’ total lift performance for Flight VS05 was estimated at 3,200 kg., which includes a combined mass of approximately 2,800 kg. for the four satellites.
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 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.
Arianespace had already conducted four 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 in December 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.
Despite both the Soyuz for this mission and the Soyuz carrying Resurs-R launching around two hours apart – a coincidence caused by a 24 hour scrub due to weather constraints for the O3B mission – Tuesday’s launches did not set a record for the shortest gap between two launches of the same family of rocket.
That record is was broken on 18 August 1960 when the US Air Force conducted two Thor launches less than two minutes apart – involving a Thor DM-18 Agena-A lifting off from Vandenberg Air Force Base, followed by a Thor DM-21 AbleStar from Cape Canaveral, which failed to orbit.
The next Soyuz launch after the O3b mission is expected to occur on 27 July, with a Soyuz-U orbiting Progress M-20M, a cargo spacecraft bound for the International Space Station.
Before that, Russia’s next launch is currently scheduled for Thursday, with the Strela rocket making its much-delayed second launch carrying a Kondor radar imaging satellite.
(Images via ESA).