Latest Galileo satellites head for space on European Ariane 5 launcher

On 25 July 2018 at 13:25 CEST (08:25 local time), four more satellites for the Galileo civil European navigation system will be launched into space on board an Ariane-5 launcher from the European spaceport in Kourou (French Guiana). The Galileo ‘family’ will have 26 members with the addition of ‘Tara’, ‘Samuel’, ‘Anna’ and ‘Ellen’, each of which weighs the same as their predecessors – 715 kilograms. “All of the satellites will orbit Earth at an altitude of 23,222 kilometres. Accordingly, our constellation is almost complete and can now ensure almost complete global coverage with Galileo signals,” reports René Kleeßen, Galileo Programme Manager at the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) Space Administration in Bonn.

What this means for practical purposes is that from the beginning of 2019 – provided that the four satellites now being launched are operating correctly – users will be able to navigate using only signals from Galileo. Until that stage is reached, it will only have been possible to navigate in conjunction with GPS navigation services that are controlled by the military (USA), Glonass (Russia) or Beidou (China). All Galileo services should be available worldwide by 2020. “Ultimately, there will be at least 30 Galileo satellites in orbit around Earth. With two ground control centres and several receiving and transmitting stations, the system’s reliable and highly-accurate operation is assured. Each Galileo satellite is equipped with highly accurate atomic clocks that enable a measurement accuracy better than one metre. In order to achieve precise positioning, we need signals from at least four satellites,” explains Kleeßen, who is a space systems engineer. The reliability of worldwide data reception will be enhanced thanks to Galileo, although – as before – it will not be possible to provide a 100 percent guarantee of navigation signal availability in relatively inaccessible areas such as the ‘canyons’ between tall buildings or in mountainous areas.

It takes approximately 14 hours for a Galileo satellite to orbit Earth, and worldwide there are just 17 locations – with several ground stations in some cases – where Galileo signals can be received and processed, and these locations range from Svalbard (on Spitsbergen) through Troll in the Antarctic, and from Tahiti to La Réunion.

Countdown commences in the evening leading up to launch

According to information released by the European Space Agency (ESA), the countdown for the launch of the 99th Ariane 5 flight is to commence as early as 23:00 – Kourou local time – on the evening of 24 July, which will correspond to 25 July 04:00 CEST. No later than by 23 July 2018, the special ‘ES5’ Ariane 5 launcher – carrying the four Galileo satellites – will be brought from the integration hall to the launch pad, and set up for launch. This will be the last Galileo satellite launch using Ariane 5. The next launch will not be before the end of 2020. When it takes place it will be carrying further ‘Batch 3’ first generation Galileo satellites into space. This will bring the constellation to its full complement – in excess of 30 satellites. The new European Ariane 6 launch rocket will be used for this purpose.

Major growth market with social relevance

On 25 July 2018, after just four hours of flight time, ‘Tara’, ‘Samuel’, ‘Anna’ and ‘Elle’ will be inserted into their in middle Earth orbits. During their first few days in space, the four newest Galileo satellites will be managed from the French control centre in Toulouse. Matters will then be taken over by the Galileo Control Centre at DLR in Oberpfaffenhofen, which will monitor and control the full fleet of satellites in the Galileo range. “We are very proud that the European Commission and GSA (Global Navigation Satellite Systems Agency) has entrusted us with such a crucial role in Europe’s largest spaceflight programme,” asserts Simon Plum, Director of DLR GfR (which is a 100 percent owned subsidiary of DLR) and manager of the Galileo Control Centre. “With this step, we are positioning DLR – and GfR is also effectively positioning us in our capacity as DLR – in one of the largest growth markets, and one that carries a very high degree of social relevance, since chronometry and navigation information have become established as being indispensable to our daily lives.“

EU programme with essential German participation

Twenty-two individual units from the fleet, now numbering 26, were constructed by the German space company OHB. The first four Galileo satellites were produced by the Airbus aerospace group. In the summer of 2017, OHB received the order for 12 further satellites. As stated by DLR Galileo Manager René Kleeßen: “Galileo is an EU programme, and consequently – contrary to the case for ESA – there is no ‘geo-return’, that is, no guaranteed financial return corresponding to individual countries’ respective national participation, and no transparent law corresponding to national shares. This is an EU competition law issue. However, Germany has contributed approximately 20 percent of the EU financing, and approximately 20 percent is estimated to flow back from Galileo to Germany if we include the development and construction of the satellite segment.”

Fifteen December 2016 saw the initialisation of the first Galileo services: public service, search and rescue, the encrypted PRS (Public Regulated Service, reserved for sovereign users such as police, fire services and emergency services) and a high-accuracy time service. Public services can be used by anyone in possession of a smartphone or the latest-generation ‘satnav’ systems. According to a market report from the European GSA, 95 percent of all currently marketed chipsets will process Galileo signals. The service is being continually expanded with additional satellites.

A precise overview can be found Usegalileo.

ESA will be providing a livestream of the Galileo launch on 25 July 2018.