Ariane 5 lifting off four Galileo navigation satellites from Spaceport in Kourou, French Guiana. Credit: ESA.

Arianespace has launched four Galileo navigation satellites from the Guiana Space Centre in Kourou, French Guiana.

Arianespace’s Ariane 5 rocket was used to launch Galileo satellites 19–22 into their planned orbit.

Approximately 3h 36min after lift-off, the first pair of the satellites weighing 715kg was released, while the second pair separated from the rocket 20min later.

“Galileo is now an operating reality, so, in July, operational oversight of the system was passed to the GSA.”

All the satellites were released into an orbital altitude of 22,922km.

Over the coming days, they will be manoeuvred to reach their final orbits, where they are expected to undergo around six months of tests by the European Global Navigation Satellite System Agency (GSA) to prove their readiness to join the working Galileo constellation.

The latest launch has brought the number of probes in the Galileo constellation to 22.

Initial services of the constellation started on 15 December last year.

European Space Agency (ESA) navigation director Paul Verhoef said: “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.”

The proposed launch to be carried out in next year is set to bring the 24‑satellite Galileo constellation to a completion, as well as add two orbital spares.