Two Galileo Satellites Attached to Joint Dispenser

On October 20, the European Space Agency (ESA) plans to launch the first two satellites of its Galileo satellite navigation constellation. The spacecraft are now installed into their joint supporting dispenser, which will release them into their respective orbits, once they are in space.

The maneuver took place at ESA's South American spaceport, in Kourou, French Guiana, on Tuesday, October 4. The Galileo In-Orbit Validation satellites are called PFM and FM2, respectively. They are the first working spacecraft to be orbited as part of the ambitious European project.

The October 20 event will also mark another important milestone from the agency. The two satellites will launch aboard a Russian-built Soyuz delivery system, which will take off from an especially-built launch pad at Kourou.

ESA finished constructing the facility this year, under a contract with the Russian Federal Space Agency (RosCosmos). The reason for doing this is so that Europe can launch its own satellites on Russian missiles from its own facility. This reduces the costs associated with bringing Galileo online.

Everything is currently progressing smoothly towards the critically-important launch. The pad has been double- and triple-checked, the satellites' vital signs are in order, and the Soyuz rocket is also ready to use. PFM and FM2 were also fueled last week, with enough propellant to last them 12+ years.

“The Galileo launch dispenser, designed for Arianespace by RUAG Space Sweden, secures the satellites in place during the take-off of their Soyuz ST-B. The satellites remain attached to the dispenser for a total of four hours after launch,” an ESA press release announces.

After the Russian rocket reaches orbit, its Fregat-MT upper stage will fire up its engines, and deliver the dispenser to an altitude of about 23,222 kilometers (14,430 miles). Once in position, the device will fire a pyrotechnic charge that will send the satellites flying in opposite directions.

The dispenser is scheduled to be integrated with the Fregat-MT upper stage next week. ESA also plans to have the Soyuz rocket integrated with the upper stage at that time, and then move both to the pad.

“The Fregat upper stage, meanwhile, was transferred on Thursday [October 6] from its fueling hall in S3B to the Upper Composite Integration Stand in that same building where it awaits the arrival of the payload stack for final upper-stage integration on Monday,” October 10, the statement adds.

“The first two Galileo IOV satellites, launched this month, will be followed next year by two more. This quartet of satellites, built by a consortium led by EADS Astrium Germany, will form the operational nucleus of the full Galileo satnav constellation,” the release concludes.