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Europe's new Galileo satellites are placed into 'wrong orbit'

Elizabeth Howell, News Writer
Aug 23, 2014, 16:27 UTC

Sen—Two new Galileo satellites were launched into space yesterday, 22 August, to push Europe's navigation system into its operational phase. But within hours, launch company Arianespace announced that an anomaly had put the craft in the wrong orbit.

Galileos 5 and 6 flew into orbit aboard a Soyuz rocket from French Guiana. The satellites separated as planned from the third stage of the rocket about 3 hours and 47 minutes after blastoff, at an altitude of about 23 500 km (14 600 miles).

Then mission controllers at Arianespace said that observations gathered after separation had highlighted a discrepancy between targeted and reached orbit. The problem was being investigated.

The European Space Agency (ESA) said in a statement: "Following the announcement made by Arianespace on the anomalies of the orbit injection of the Galileo satellites, the teams of industries and agencies involved in the early operations of the satellites are investigating the potential implications on the mission.

"Both satellites have been acquired and are safely controlled and operated from ESOC, ESA's Operations Centre in Darmstadt, Germany. Further information on the status of the satellites will be made available after the preliminary analysis of the situation."

The European Space Agency and CNES (France's space agency) had been due to check the satellites' health before giving control to the Galileo Control Centre in Oberpfaffenhofen, Germany, and the Galileo in-orbit Testing facility in Redu, Belgium. Operations were expected to start in the autumn.

The satellites join four that are successfully working in orbit, and there are many more to come. Officials expect to launch six to eight satellites a year until the final constellation goal of 24 satellites is reached in 2017. Six on-orbit spares will also be available at that time.

The roots of Galileo come from a couple of decades ago, when European officials determined it was in the best interest to make a civilian version of GPS for autonomy.

The first Galileo In-Orbit Validation Element (GIOVE) satellite was launched in December 2005, followed by GIOVE-B in 2008. The two satellites' timing signals worked as expected, paving the way for the Galileo system to come up next.

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Artist's impression of the complete Galileo satellite navigation system of 24 satellites and six spares. Image credit: ESA-P. Carril

The first pair of Galileo satellites launched in October 2011, with two others following in October 2012. These four satellites were enough to start testing of Galileo's positional accuracy.

"The single most important finding from the test results? Galileo works, and it works well. The entire self-sufficient system has been shown as capable of performing positioning fixes across the planet," the European Space Agency stated before the new orbit anomaly was revealed.

"Galileo’s observed dual-frequency positioning accuracy is an average 8 m horizontal and 9 m vertical, 95 per cent of the time. Its average timing accuracy is 10 billionths of a second—and its performance is set to sharpen as more satellites are launched and ground stations come on line."

Additional reporting by Paul Sutherland