Inmarsat’s first dual-band satellite is launched by MHI

On December 22, Inmarsat launched its first-ever dual-band telecommunications satellite atop a Mitsubishi Heavy Industries H-2A rocket. At 10:32 a.m. Eastern, the rocket blasted off from Japan’s Tanegashima Space Center, putting the Inmarsat-6 F1 satellite into the geostationary transfer orbit (GEO) 26 minutes later. Inmarsat, based in London, tweeted a little over two hours later that it had received initial telemetry from the spacecraft.

The deployment was the H-2A’s 45th overall and 38th successful flight since a failure in 2003. This year, the workhorse rocket flew one more mission, delivering a Quasi-Zenith navigation spacecraft for the Japanese government in October. Inmarsat-6 F1 (I-6 F), which is powered entirely by electricity, will take around 200 days to reach its geostationary orbit above the Indian Ocean.

I-6 F1 will be the first of two satellites fitted with a hybrid L- plus Ka-band payload that Inmarsat has ordered from Europe’s Airbus Defence and Space. The next satellite, I-6 F2, is set to fly next year aboard an unnamed rocket. The satellites’ dual-band payload will be used by Inmarsat to deliver mobility connectivity services to the aviation, maritime, and government markets.

L-band, which is typically used for voice conversations and messaging but is rapidly finding applications for monitoring and tracking objects outside the range of terrestrial communications networks, has a nine-meter aperture antenna on the I-6 F1. For video and other high-throughput applications, the satellite has 9 steerable multi-beam Ka-band antennas.

Inmarsat’s eight-satellite ELERA network currently provides L-band services, while its 5-satellite Global Xpress constellation provides Ka-band services. I-6 F1 twice the capacity and power per beam of Inmarsat’s preceding Inmarsat-4 family of L-band satellites, according to the operator.

Inmarsat’s last L-band satellite, Inmarsat-4A F4, or Alphasat, was launched in 2013. In addition to I-6 F2, Airbus is now working on 3 more Global Xpress satellites for Inmarsat (GX7, 8, and 9) that will be put into geostationary orbit in 2023.

Inmarsat also has the Global Xpress payloads, called GX10B and GX10A, on two satellites being built by Northrop Grumman in the United States for Space Norway, a Norwegian government-controlled enterprise. Next year, SpaceX plans to deploy those satellites into a highly elliptical orbit for Arctic coverage. In July, Inmarsat announced intentions to add low-Earth orbit satellites to the mix as part of a multi-orbit constellation codenamed Orchestra in order to better support global mobility markets. Viasat, a satellite operator based in the United States, revealed plans in November to buy Inmarsat for $7.3 billion in order to extend its Ka-band GEO network over different orbits and frequency bands.

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