Inmarsat satellite ready for liftoff on Proton rocket

A Proton rocket is poised for launch Sunday with the Inmarsat 5 F2 mobile communications satellite. Credit: Roscosmos
A Proton rocket is poised for launch Sunday with the Inmarsat 5 F2 mobile communications satellite. Credit: Roscosmos

A Russian Proton rocket is scheduled to take off from Kazakhstan on Sunday with the second spacecraft to serve Inmarsat’s $1.6 billion next-generation satellite communications network geared for getting faster links to customers on the move.

The launcher rolled out of its assembly hangar at the Baikonur Cosmodrome on Thursday, riding on its side aboard a rail car for the journey to a launch pad at the spaceport’s Complex 200 launch facility.

Once at the launch pad, the 19-story rocket was hoisted upright and a mobile gantry wheeled into position to give ground crews access to the booster for final preparations.

Liftoff is set for 1231 GMT (7:31 a.m. EST) Sunday, but it will take more than 15 hours for the Proton rocket and a Breeze M space maneuvering tug to release the Inmarsat 5 F2 satellite in a planned orbit with a high point of 65,000 kilometers (40,389 miles), a low point of 4,341 kilometers (2,697 miles) and an inclination of around 26.75 degrees.

The flight will be the first Proton mission of 2015. It is managed under the auspices of International Launch Services, the Virginia-based company that arranges commercial Proton launches.

ILS is a subsidiary of the Khrunichev State Research and Production Space Center, prime contractor for the Proton rocket.

Built by Boeing Satellite Systems International Inc. in El Segundo, California, the 6.7-ton spacecraft will fire its on-board engine to reach a circular orbit 22,300 miles over the equator a few weeks after launch.

The spacecraft — about the size of a London double-decker bus — will extend power-generating solar panels to a span of 111 feet.

Artist's concept of a Global Xpress satellite. Credit: Inmarsat
Artist’s concept of a Global Xpress satellite. Credit: Inmarsat

Furnished with 89 fixed and steerable spot beams, the satellite will be the second craft to launch for Inmarsat’s Global Xpress service, which aims to boost connectivity speeds for customers on airplanes, at sea, and in other remote regions worldwide.

Inmarsat’s previous satellites broadcast in L-band frequencies, but the company switched to Ka-band for the Global Xpress system, offering improved downlink communications speeds to 50 megabits per second, with up to 5 megabits per second on the uplink side.

And users can link up with the Global Xpress satellites with smaller terminals, easing restrictions on antennas size for customers on the go.

Inmarsat counts maritime operators and airlines among its customers, allowing ships and planes to remain connected while traveling through remote oceans and skies.

The improved broadband connections will give airline passengers more options for entertainment and work while in the air, and could help air traffic controllers and airlines track the status of jumbo jets flying outside the reach of terrestrial radars.

Such a capability became vogue after the loss of Malaysia Airlines Flight MH370 in March 2014. Inmarsat engineers tracked ping signals the company’s satellites received from the lost airliner and helped investigators conclude the plane likely went down somewhere in the southern Indian Ocean.

No trace of the jet has been found.

Inmarsat proposed a free global airplane tracking service in May 2014 for all commercial airplanes fitted with the the company’s satellite transmitters.

Inmarsat’s first Global Xpress satellite launched in December 2013. Launches of the next two spacecraft were delayed after a Proton launch failure in May 2014 that left the booster grounded for four months.

Russia sent up two government missions on Proton launches in September and October before the rocket returned to commercial service with a pair of flights for Gazprom Space Systems and SES in December.

The Inmarsat 5 F1 spacecraft deployed in December 2013 covers the Indian Ocean, the Middle East, Europe and Africa. The satellite set for launch Sunday will be positioned over the Atlantic Ocean and the Americas.

A third Global Xpress satellite has completed ground testing and is due for liftoff in the second quarter of 2015, allowing Inmarsat to commence global service by mid-year. Boeing is manufacturing a spare fourth Inmarsat 5 satellite, with delivery expected in late 2016.

But Inmarsat’s clients are already using the Global Xpress system.

Britain’s Sky News broadcasted the first live, on-air transmission through Global Xpress to support the networks’s coverage of the Jan. 25 Greek election.

“GX represents a significant opportunity for media,” said Martin Turner, director of media at Inmarsat Enterprise, in a press release. “The ability to live stream HD content to news-hungry audiences worldwide is crucial in a competitive industry and we are proud to be able to deliver a service that enables the world’s media to do just that; no matter how remote their location. Reliability, speed and quality are of unique importance to our media customers and we will continue to deliver on these areas, supported by a suite of terminals, when the GX network becomes fully operational.”

Follow Stephen Clark on Twitter: @StephenClark1.