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Nov 23, 2014

Galileo Started Badly (August 22, 2014)

Europe's satellite navigation system Galileo's full operational capability (FOC) phase started badly (22.8.2014) due to a design error in the Russian launch vehicle Soyuz-STB Fregat-MT. This is the first partial failure since 2011 for the Soyuz vehicle and about 20 successful launches since the 2011 failure. The problem left the pair of satellites (FOC-1 and FOC-2) in the wrong orbit, with higher apogee, lower perigee and an incorrect inclination compared to the planned circular orbit (see below).

[News update Jan. 5, 2015: After some maneuvers the FOC-1 orbit could be fixed to some degree and the same recovery maneuvers are planned for the sixth satellite (FOC-2), taking it into the same orbital plane but on the opposite side of Earth. The decision whether to use the two satellites for Navigation and SAR purposes as part of the Galileo constellation will be taken by the European Commission based on the test results later.]

Galileo FOC-1 and FOC-2 orbit errors

“After launch, we quickly discovered that one of each satellite’s pair of solar wings had not deployed correctly,” says Liviu Stefanov, Spacecraft Operations Manager. “At the same time, difficulties in receiving radio signals – indicated by unusually low power and instability – alerted us to the fact that the orbits could be incorrect. Basically, the ground stations were pointing to where we expected the satellites to be, and they weren’t there, so we weren’t getting good signals.”

It took three days to release the trapped solar wing of the first satellite, and then two days later the second Galileo’s stuck array was also freed.

Galileo FOC Satellites

It was determined that the best course of action would be to dedicate most of the vehicle’s propellant to raising the perigee (lowest point) of the orbit from 13,713 to 17,339 Kilometers. Once in that orbit, the satellite would be out of the most intense areas of radiation. Although the two spacecraft will not reach  their nominal working orbit, “the new orbit will fly over the same location every 20 days,” said Daniel  Navarro-Reyes, ESA Galileo mission analyst. “The standard Galileo repeat pattern is every 10 days, so achieving this will synchronize the ground track with the rest of the Galileo satellites.”

Soyuz 2-1B, Galileo FOC-1 and 2 Launch, August 22, 2014

Galileo FM01 is a 733-kg (660 kg dry) navigation satellite, one of the first two Full Operational Capability (FOC) satellites. These satellites carry two rubidium and two hydrogen maser atomic clocks and broadcast on L-band. They also carry the MEOSAR search and rescue transponder payload. They are built by OHB (Bremen) with navigation payloads by SSTL (Guildford). The earlier IOV test satellites were partly owned by ESA, but the FOC satellites are owned by the European Union's GSA (Global Navigation Satellite Systems Agency).

The spacecraft were placed in a wrong orbit. As planned, the Fregat upper stage made its first burn to put both satellites into in elliptical transfer orbit and then made a second burn intended to circularize the orbit at 23,500 km, inclined at 55.0 degrees. Unfortunately, the orbit was 13,700 km x 25,900 km, inclined at 49.7 degres, more elliptical than planned and with the wrong orbital inclination.

Russian officials report that the failure of the Fregat stage was caused when a cryogenic helium line installed too close to a hydrazine propellant supply line caused the hydrazine to freeze. The root cause was a design error, not a quality control error.

On 22 August, at 12:27 GMT/14:27 CEST, a Soyuz rocket launched Europe’s fifth and six Galileo satellites from Europe's Spaceport in Kourou, French Guiana. Rewatch the moment of launch here.






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