Proton Delivers Inmarsat Global Xpress Satellite to GTO

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PARIS — A Russian Proton heavy-lift rocket on Aug. 29 successfully placed an Inmarsat commercial mobile communications satellite into geostationary transfer orbit in the vehicle’s first launch since a May failure.

​London-based Inmarsat confirmed that the satellite was healthy and had been placed in the correct super-synchronous transfer orbit 15 hours and 31 minutes after the launch from Russia’s Baikonur Cosmodrome in Kazakhstan.

​Proton’s commercial sales operator, International Launch Services (ILS) of Reston, Virginia, and Russia’s Roscosmos space agency said Proton’s Breeze-M upper stage had delivered the 6,000-kilogram Inmarsat 5 F3 into the designated parking orbit after five ignition-and-coast phases.

​The launch should begin to relieve the strain on commercial launch manifests that has developed since Proton’s May failure, which destroyed Mexico’s Centenario mobile telecommunications satellite; and the June 28 failure of the SpaceX Falcon 9 v1.1 rocket carrying supplies to the international space station.

​Hawthorne, California-based SpaceX in the past two years has replaced Proton as second commercial-launch workhorse alongside Europe’s Ariane 5 vehicle. SpaceX, which has a long list of commercial customers awaiting launch, has yet to confirm whether it will be able to return to flight this autumn.

ILS Manifest

​With the latest success, ILS now plans to launch one more commercial mission – Turksat of Turkey’s Turksat 4B telecommunications satellite — in 2015. Like Inmarsat 5F3, Turksat 4B is about a year behind schedule owing to Proton’s multiple delays following failures in each of the past four years.

​ILS said Paris-based Eutelsat’s Eutelsat 9B satellite would be next up on Proton’s commercial manifest, with a launch set for early 2016. Proton’s workload is divided between commercial ILS missions and Russian Federal missions, which in the coming months include a January 2016 launch of a Euro-Russian Mars orbiter and lander.

​For Inmarsat, the launch ends a year of frustration as it awaited the completion of its $1.2 billion Global Xpress network, which requires three satellites in geostationary orbit to provide seamless global coverage, with the exception of the polar region.

​“We have been working towards this day ever since we announced plans to create the Global Xpress constellation in 2010,” Inmarsat Chief Executive Rupert Pearce said in an Aug. 29 statement confirming the launch success. “I am delighted that we now have three Global Xpress satellites in orbit, enabling us to provide global GX services by the end of the year.”

​In a decision that raised risk-mitigation questions at the time, Inmarsat elected to launch all three Global Xpress satellites aboard Proton rockets. The first two were successfully orbited in December 2013 and February of this year as Inmarsat, in what appears to have been no more than the luck of the draw, placed the satellites into service in between Proton failures.

​The first Global Xpress satellite entered service in July 2014, with the second declared fully operational earlier this month. Inmarsat officials had told investors that while initial Global Xpress services could begin with these two spacecraft, the big customer accounts – including the U.S. Department of Defense – would not sign on fully until the global network was in place.

​The three Global Xpress satellites were built by Boeing Space and Intelligence Systems of El Segundo, California, which in return for the business agreed to a take-or-pay commitment with Inmarsat that gives Boeing chief responsibility for sales to U.S. military customers.

Global Xpress. Credit: Boeing
Global Xpress. Credit: Boeing

​Each Global Xpress has 80 Ka-band spot beams. The design features a High-Capacity Overlay using the military Ka-band frequencies, which are next to the commercial/civil Ka-band frequencies.

​Inmarsat has signed an agreement with the U.S. Defense Department that makes Global Xpress interoperable with the U.S. Wideband Global System (WGS) satellites.

​Seven WGS satellites, also built by Boeing, are in orbit, with the seventh featuring a higher-capacity payload than the earlier versions. An eighth WGS is scheduled for launch in mid-2016, with two more planned after that.

​Inmarsat has stressed the relative flexibility of the Global Xpress design compared to WGS and expects U.S. military forces to use Inmarsat to fill in coverage or capacity not provided by WGS.

​On the commercial side, Global Xpress moves Inmarsat beyond its heritage L-band narrowband mobile communications links into the broadband market.

​Pearce told investors on Aug. 6 that the yearlong delay in Global Xpress would defer, but not remove, the service’s sales promise. Inmarsat has said Global Xpress will generate $500 million in annual revenue after five years of operations, which now means by the end of 2020.