The European satellite navigation system Galileo has reached another milestone: Milena and Doresa, the fifth and sixth satellites of a group of 30, were launched from the European space port in Kourou (French Guiana) on board a Russian Soyuz rocket. The launch, which was delayed by one day, took place on 22 August 2014 at 2:27 p.m. Central European Summer Time (CEST), 9:27 a.m. local time. These are the two first Galileo satellites of the deployment phase. Four satellites have been in space since 2011 and 2012 for the in-orbit validation of the system.
The two navigation satellites, built by German space systems manufacturer OHB in Bremen, were expected to reach their destination orbit – the medium Earth orbit at a height of approximately 23,500 kilometres – by 6:15 p.m. CEST. “Germany has a 20 per cent stake in Galileo,” said René Kleeßen, Galileo programme manager for aerospace management at the German Aerospace Centre (DLR). “We represent Germany’s interests in Galileo at the ESA Programme Board on Navigation and advise the Ministry of Transport on the European GNSS (Global Navigation Satellite System) committee in its dealings with the European Commission.”
The European Commission initiated the navigation programme, and the European Space Agency ESA negotiates industry contracts on its behalf. As well as being a location for satellite manufacturers, Germany is home to one of the two Galileo Control Centres. It is situated at the DLR in Oberpfaffenhofen. “Germany and Italy also jointly run the Galileo operating company spaceopal,” said René Kleeßen. The DLR aerospace management department is also responsible for setting up the Galileo test areas, or GATEs, in Germany. Together with geoinformation and telecommunications, Galileo can be used for a diverse range of purposes – including autonomous driving in traffic, monitoring fish stocks, and search and rescue services.
The launch of the two first OHB satellites formally signifies the completion of Galileo development phase. The in-orbit validation phase was performed by the first four satellites, built by Airbus Defence and Space, which were launched in October 2011 and October 2012. The first position with Galileo signals was transmitted with these four satellites in March 2013.
The European Commission has ordered 22 satellites in total from OHB in Bremen for the deployment phase (FOC, Full Operational Capability) which is now beginning. Two more FOC satellites will follow in late 2014. “Galileo was expected to be fully functional back in 2008, but as with all large and complex space programmes, delays occurred. The GPS system has 20 years more experience and we first needed to catch up with it,” said DLR programme manager Kleeßen. Together with the American GPS, the Russian GLONASS and the Chinese Beidou, which is also in development, four satellite navigation systems will exist globally in a few years time.
Complex physics – wide-ranging applications
“The physics is the same everywhere – in other words, all satellites work with similar technology, such as high-precision atomic clocks. But unlike GPS, GLONASS and Beidou, Galileo is under civil control,” explained aerospace engineer Kleeßen. Galileo will offer four services in total: an open service with accuracy of around four metres (by comparison, here GPS only has a resolution of approximately ten metres); a commercial service with greater precision of up to one metre; a service with encrypted signals for authorised users, mainly public authorities; and a search and rescue service. According to DLR programme manager Kleeßen: “Galileo’s measured performance values are better than those of GPS, but the particular challenge is the robustness of the system.”
The first services are expected to be ready for use by early 2015 and be fully established by 2020. The total costs for the development and construction of Galileo are in the region of six billion Euro. For operation and further development of the system and of the European GPS augmentation system EGNOS (European Geostationary Navigation Overlay System), further seven billion Euro are settled in the EU budget for the period 2014–2020.
The first FOC satellites now being launched cost around 40 million Euro each. Eight other German companies are involved in the programme besides OHB System AG as ESA main contractor.