Successful Galileo Launch Paves Way for Service Debut
PARIS — A Europeanized Russian Soyuz rocket on Dec. 17 successfully placed two European Galileo positioning, navigation and timing satellites into orbit, a launch expected to permit initial Galileo services by late 2016.
The launch, from Europe’s Guiana Space Center on the northeast coast of South America, inserted the 11th and 12th Galileo satellites into medium Earth orbit in the third Soyuz Galileo flight in 2015. It was the 12th launch overall by Europe’s Arianespace launch consortium, a record for the company, with three Soyuz launches, three Vega small-satellite missions and six heavy-lift Ariane 5 rocket campaigns.
Assuming the two latest Galileo satellites are without defect, there will be nine fully operational Galileo satellites by late 2016, enabling the European Commission — the executive arm of the 28-nation European Union — to debut service provision.
Three of the 12 satellites in orbit have problems that might prevent them from offering all Galileo services.
Two of those satellites, launched in 2014, were placed in a bad orbit by the Soyuz vehicle’s Fregat upper stage.
While it appears that corrective measures undertaken since then by the European Space Agency will enable these two satellites to provide most Galileo services despite their poor orbit, they might not be able to furnish Galileo’s Public Regulated Service (PRS), an encrypted, government-only signal that is equivalent to the U.S. GPS satellites’ military code.
In addition, one of the four Galileo in-orbit-validation satellites has suffered an apparently irreparable power degradation, meaning it might never provide the full complement of Galileo services — an Open Service, free of charge to all users; a Search and Rescue (SAR) service; a Commercial Service; and PRS.
“The target is initial service next year, with a reduced constellation, for the Open Service, PRS and SAR,” said Carlo des Dorides, executive director of the European GNSS Agency, based in Prague.
“We will also start proof-of-concept testing for the Commercial Service. The performance will be reduced in terms of availability and continuity because of the reduced number of satellites — but not in terms of accuracy,” des Dorides said during a Dec. 16 press briefing.
Galileo is designed as a 30-satellite constellation — 24 operational satellites and six in-orbit spares, with two more spares on the ground. The European Commission and ESA have set a goal of having all 30 satellites launched by 2020.
The delays that have long plagued the Galileo program now appear to be a thing of the past. Didier Faivre, ESA’s navigation director, said the speed and smoothness of the recent production and testing of Galileo satellites — built by prime contractor OHB SE of Bremen, Germany with a payload built by Surrey Satellite Technology Ltd. of Britain — means the 30-by-2020 goal is well within reach.
All 12 in-orbit Galileo satellites have been launched in pairs aboard Europeanized Soyuz vehicles. Starting next year that will change. Faivre told the briefing that the first use of Europe’s Ariane 5 rocket for Galileo deployment will occur sometime between September and November. The rocket will carry four satellites.
The Ariane 5 ES rocket — with a storable-propellant upper stage — has never been used aside from the launches of five Automated Transfer Vehicle cargo vehicles to the International Space Station, at 400 kilometers in altitude. This will thus be a new mission profile for Ariane 5.
The flight also will feature a newly designed satellite dispenser to hold the four satellites under the rocket’s fairing and then jettison them in orbit.
Faivre said the Ariane 5 ES and the dispenser are scheduled to complete their qualification testing in the first half of 2016 to be ready for the launch.
Following the Ariane 5 mission, another Soyuz will launch two more Galileo satellites in late 2016 or early 2017, depending on the schedule constraints of launch service provider Arianespace of Evry, France.
Two more Ariane 5 rockets — one in mid-2017 and another in 2018 — will bring the constellation to a total of 26 satellites, which is all that have been ordered so far by the European Commission.
To assure a 30-satellite system and to give the program a safety margin, the European Commission has opened an invitation to tender for eight more Galileo satellites.
Paul Flament, a Galileo program manager at the commission’s Directorate-General for the Internal Market, Industry, Entrepreneurship and Small and Medium-sized Enterprises — DG Growth for short — said the commission would select a winning bidder by September.
The four Galileo validation satellites were built by a consortium led by Airbus Defence and Space and Thales Alenia Space. The commission then scheduled a two-part competition won by OHB for a total of 22 satellites.
Flament said the eight satellites to be ordered in 2016 will not be much different from the 22 built by OHB. The commission’s rules, he said, oblige a fresh competitive bidding process even if the next contract would appear to be OHB’s to lose.
Flament said the commission has no choice but to open the solicitation to any companies wishing to bid. He recalled that OHB won the Galileo business despite the fact that its competitors built the earlier satellites.
Faivre said the fact that the order will be for satellites with no material differences from the current OHB production line is one reason for optimism that they will be ready for launch in 2020.
Source: Space News
17 Dec, 2015
Successful Galileo Launch Paves Way for Service Debut
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