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Soyuz rocket launches Galileo satellites

Anatoly Zak, Spaceflight Correspondent
Mar 28, 2015, 16:33 UTC

Sen—Seven months after dropping a pair of Galileo satellites in a wrong orbit, the Soyuz rocket righted itself Friday, March 27, delivering two fresh navigation birds for Europe's own global-positioning constellation.

The Russian-built Soyuz-ST launch vehicle lifted off from the European launch facility on a jungle-covered South-American shore of French Guiana at 6:46 p.m. local time (21:46 UTC).

The rocket carried a second pair of 715-kilogram satellites nick-named Adam and Anastasia and intended for the Full Operational Capacity (FOC) of the Galileo navigation network, after nearly a decade-long in-orbit testing of experimental spacecraft.

The first attempt to press Galileo satellites into service on Aug. 22, 2015, ended in a heartbreak for the project's engineers, when the Fregat stage at the top of the Soyuz rocket failed during the three-hour, 47-minute process of delivering spacecraft from Earth to their 23,522-kilometer circular orbit.

Demonstrating one more time the unforgiving nature of spaceflight, an obscure design flaw in the Fregat's interior caused its thrusters to freeze and stall, leaving precious satellites in a lower-than-expected, egg-shaped orbit.

Propulsion systems onboard Galileo satellites had never been designed for such a major orbit correction, but in the following days and weeks, engineers managed to establish full control over the wayward pair and even promised to bring the spacecraft into operation thanks to clever software upgrades. In the meantime, Russian engineers found and fixed the problem in the Fregat.

As a result, all eyes during the Friday launch were on the Fregat's performance. Fortunately, everything went by the book this time and the doughnut-shaped space tug released Adam and Anastasia on time and into the right orbit.

The satellites have an operational warranty of at least 12 years in space, long enough to see the entire Galileo constellation to be deployed in orbit.

The network is expected to enter limited service as early as 2016 with 12 satellites in orbit and expanded to 30 satellites with maximum capacity around 2020.

The Galileo constellation joins the American GPS, Russian GLONASS and Chinese Beidou satellite navigation systems.