Galileo Satellites Not in Expected Orbit

After the separation of the two Galileo satellites launched August 22, ongoing analysis of the data provided by the telemetry stations operated by the European Space Agency (ESA) and the French space agency CNES showed that the satellites were not in the expected orbit.

According to the initial analyses, an anomaly is thought to have occurred during the flight phase involving the Fregat upper stage, causing the satellites to be injected into a noncompliant orbit.

UPDATE: Inquiry Commission Appointed Following Galileo Anomaly

The liftoff and first part of the mission proceeded nominally, reports Arianespace, leading to release of the satellites according to the planned timetable, and reception of signals from the satellites. However, the targeted orbit was circular, inclined at 55 degrees with a semi major axis of 29,900 kilometers. The satellites are now in an elliptical orbit, with excentricity of 0.23, a semi major axis of 26,200 km and inclined at 49.8 degrees.

Both the Fregat upper stage and the two satellites are in a stable condition and position that entails no risk for people on the ground. The residual propellants on the Fregat stage have been purged and the stage was depressurized normally.

Studies and data analyses are continuing in Kourou, French Guiana, and at Arianespace headquarters in Evry, near Paris, under the direction of Stéphane Israël, Chairman and CEO of Arianespace, in conjunction with the Russian partners in the Soyuz in French Guiana program (Russian space agency Roscomos and the manufacturers RKTs-Progress and NPO Lavotchkine), as well as Arianespace’s customer ESA and its industrial partners, to determine the scope of the anomaly and its impact on the mission.

Following the announcement made by Arianespace on the anomalies of the orbit injection of the Galileo satellites, ESA said that 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.

“Our aim is of course to fully understand this anomaly,” said Stéphane Israël, Chairman and CEO of Arianespace. “Everybody at Arianespace is totally focused on meeting this objective. Starting Monday, Arianespace, in association with ESA and the European Commission, will designate an independent inquiry board to determine the exact causes of this anomaly and to draw conclusions and develop corrective actions that will allow us to resume launches of Soyuz from the Guiana Space Center (CSG) in complete safety and as quickly as possible. The board will coordinate its work with Russian partners in the Soyuz at CSG program. Arianespace is determined to help meet the European Union’s goals for the Galileo program without undue delay. We would like to thank ESA, the European Commission and CNES for the very productive discussions since becoming aware of the occurrence of the anomaly. While it is too early to determine the exact causes, we would like to offer our sincere excuses to ESA and the European Commission for this orbital injection that did not meet expectations.”