The latest two satellites to be launched by Arianespace for Europe’s Galileo navigation system are being fueled at the Spaceport in French Guiana, readying them for this month’s Soyuz mission.
Named “Doresa” and “Milena,” both spacecraft are in the Spaceport’s S5 payload preparation building, where they are being “topped off” with the onboard fuel load. Their liftoff is scheduled for August 21 on Arianespace Flight VS09 – the company’s ninth mission of its medium-lift workhorse launcher performed from French Guiana.
These are the first FOC (Full Operational Capability) satellites for the Galileo constellation, which will create a European-operated space-based navigation system providing highly accurate, guaranteed global positioning services. Galileo’s FOC phase is being funded and executed by the European Union, which has designated the European Space Agency as the system’s development and sourcing agent.
“Doresa” and “Milena” were built in Bremen, Germany by FOC prime contractor OHB System, and are named for children who were among those winning a European Commission-organized painting competition in 2011. The spacecraft payloads, which will generate precision positioning measurements and services to users worldwide, were supplied by Surrey Satellite Technology Ltd. in Guildford, UK.
This month’s Flight VS09 will be the latest launch in Galileo’s overall system development, which began with the lofting of two GIOVE (Galileo In-Orbit Validation Element) satellites in December 2005 and April 2008 on Soyuz missions operated by Arianespace’s Starsem affiliate from Baikonur Cosmodrome in Kazakhstan.
It was followed by four Galileo satellites used for the system’s In-Orbit Validation (IOV) phase, launched in pairs on Soyuz flights performed by Arianespace from French Guiana in October 2011 and October 2012. Lofted on the historic first and third flights conducted with Soyuz at the Spaceport, these four IOV spacecraft enabled testing of the full Galileo system, clearing the way for the FOC phase.
The complete Galileo constellation is to be composed of 27 operational satellites and three reserves, distributed along three circular medium Earth orbit planes at an altitude of 23,222 km., inclined 56 deg. to the equator. By being interoperable with the existing U.S. GPS and Russian Glonass navigation systems, Galileo will become another cornerstone in global satellite navigation.
Galileo will function under civilian control and allows position locating to be determined accurately for most places on Earth, even in cities where high-rise buildings can obscure signals from satellites that appear low on the horizon. This is because the overall number of available Galileo satellites is more than doubled, and the spacecraft are situated in orbits at a greater inclination to the equatorial plane than GPS – giving better coverage at high latitudes, including northern Europe.
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