Four more Galileo satellites launched into orbit

Updated with additional details and reaction.

Liftoff of Ariane 5 Flight VA240 from Europe’s Spaceport in Kourou took place at 18:36 UTC on Dec. 12, 2017, carrying Galileo satellites 19–22. (Photo: ESA)

On Dec. 12, four more Galileo satellites headed into space to join the navigation constellation. Galileos 19–22 lifted off aboard an Ariane 5 rocket from Europe’s Spaceport in Kourou, French Guiana, at 18:36 UTC (19:36 CET, 15:36 local time).

After today’s successful launch, only one more launch remains before the Galileo constellation is complete and delivering global coverage.

Separation of the upper stage occurred about nine minutes after liftoff, followed by the first firing of the upper stage.

The first pair of 715-kg satellites was released almost 3 hours 36 minutes after liftoff, while the second pair separated 20 minutes later.

They were released into their target 22,922 km-altitude orbit by the dispenser atop the Ariane 5 upper stage. In the coming days, this quartet will be steered into their final working orbits. There, they will begin around six months of tests — performed by the European Global Navigation Satellite System Agency (GSA) — to check they are ready to join the working Galileo constellation.

This mission brings the Galileo system to 22 satellites. Initial Services began almost a year ago, on Dec. 15, 2016.

“Today’s launch is another great achievement, taking us within one step of completing the constellation,” remarked Jan Wörner, ESA’s director general.

“It is a great achievement of our industrial partners OHB (DE) and SSTL (GB) for the satellites, as well as Thales-Alenia-Space (FR, IT) and Airbus Defense and Space (GB, FR) for the ground segment and all their subcontractors throughout Europe, that Europe now has a formidable global satellite navigation system with remarkable performance.”

Paul Verhoef, ESA’s director of navigation, added, “ESA is the design agent, system engineer and procurement agent of Galileo on behalf of the European Commission. Galileo is now an operating reality, so, in July, operational oversight of the system was passed to the GSA.

“Accordingly, GSA took control of these satellites as soon as they separated from their launcher, with ESA maintaining an advisory role. This productive partnership will continue with the next Galileo launch, by Ariane 5 in mid-2018.

“Meanwhile, ESA is also working with the European Commission and GSA on dedicated research and development efforts and system design to begin the procurement of the Galileo Second Generation, along with other future navigation technologies.”

Next year’s launch of another quartet will bring the 24‑satellite Galileo constellation to the point of completion, plus two orbital spares.

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