ESA's Galileo Navigation System Satellite Fails to Reach Planned Orbit

The European Space Agency's (ESA) plans to construct Europe's own global satellite navigation system hit a minor snag when the two satellites, launched on August 22, failed to make it to their intended orbit. Galileo 5 and 6 were launched on a Soyuz rocket from the CSG, Europe's Spaceport in French Guiana.

On August 26, ESA said, “Despite the non-nominal orbit, the satellites are safely under control after they were released from the launcher upper stage and their orbital position was determined by the European ground teams deployed at ESOC in Darmstadt, Germany. Controllers there, in cooperation with the satellite manufacturer OHB, confirm the good health and the nominal behaviour of both satellites. A procedure to deploy the solar arrays that had remained partially folded on both satellites was successfully executed on the first satellite in the course of Monday night. A similar procedure will be executed soon on the second satellite.”

ESA said, “Both satellites continue to be kept in a safe state, correctly pointing to the Sun, properly powered and fully under control of the ESA/CNES integrated team and the teams of OHB deployed at ESA’s control centre In parallel, the teams are investigating the possibilities to exploit the satellites to their best despite the non-nominal injection orbit and within the limited propulsion capabilities of the satellites.”

This isn't the only problem facing the Galileo constellation. Peter B. de Selding, in his article Galileo Glitches Remain a Mystery, writes that on August 20, ESA said that it has still not determined what caused a sudden power drop in May aboard one of the four Galileo satellites previously launched. ESA reduced power on all four satellites by 1.5 dB as a precautionary measure. ESA officials said this small drop in power “will have no perceptible effect for Galileo system users.” Selding's article describes the ESA investigation, which includes examining different failure scenarios, asking satellite component builders to reproduce certain components for testing, and tilting the affected satellite to assess radiation pattern changes on the spacecraft's L-band antenna.

UPDATE: Rianovosti has reported the Galileo Satellites Incident Likely Result of Software Errors. An unnamed source from Russian space agency Roscosmos reportedly told Izvestia, "The nonstandard operation of the integrated management system was likely caused by an error in the embedded software. As a result, the upper stage received an incorrect flight assignment, and, operating in full accordance with the embedded software, it has delivered the units to the wrong destination."

Doug Lung is one of America's foremost authorities on broadcast RF technology. He has been with NBC since 1985 and is currently vice president of broadcast technology for NBC/Telemundo stations.