SPACEFLIGHT Communication satellites

Sixth-generation satellite

In December, Inmarsat launched I-6 F1 – the first of a new sixth-generation of high-capacity communication satellites which will work together to provide a layered network of coverage around the world. BILL READ FRAeS reports.

Immarsat

On 22 December, Inmarsat launched I-6 F1 – the first of two Inmarsat-6 (I-6) satellites from the JAXA Tanegashima Space Center in Japan. The I-6 F1 was carried into orbit aboard an H-IIA Launch Vehicle No. 45 (HIIA F45).

A leading provider of global, mobile satellite communications for the past 40 years, Inmarsat owns and operates 14 geostationary satellites in geostationary orbit 35,786km (22,236m) above the Earth. The satellites provide a multi-layered, global spectrum portfolio, covering L-band, Ka-band and S-band. Services offered include safety and missioncritical mobile broadband communications using the Global Maritime Distress and Safety System (GMDSS), approved by the International Civil Aviation Organization (ICAO).

THE I-6F1 IS CLAIMED TO BE THE LARGEST COMMERCIAL COMMUNICATIONS SATELLITE EVER LAUNCHED

Inmarsat also operates the Ka-band Global Xpress GX5 satellite high-speed mobile broadband network, as well as the ELERA Inmarsat-4 (I-4) which supports the global 3G narrowband L-band mobile connectivity network. In addition, Inmarsat operates the European Aviation Network, which combines the capabilities of its S-band satellite (I-S EAN), launched in 2017, with ground-based LTE in a hybrid air-to-ground network and Fleet Xpress, to deliver in-flight connectivity across Europe’s airspace, combining both Global Xpress Ka-band and ELERA L-band.

Inmarsat’s satellite fleet is supported by a ground network of satellite access stations (SAS) located across Europe, six new examples of which were commissioned in 2020 to support GX5.

Enter the I-6s

The newly launched sixth-generation Inmarsat-6 (I6) satellites will provide yet more capabilities. Constructed in the UK by Airbus Defence and Space, the I-6 F1 was launched from the JAXA Tanegashima Space Center in Japan aboard a H-IIA Launch Vehicle. The second I-6 will follow in 2022.

Top: I-6 satellite under construction. Middle: On 20 December Inmarsat launched I-6 F1 – the first of two Inmarsat-6 (I-6) satellites from the JAXA Tanegashima Space Center in Japan. Bottom: An artist’s impression of the new I-6.

The I-6F1 is claimed to be the largest commercial communications satellite ever launched, weighing 5,470kg with fuel. Once the solar array is extended, it will measure 47m across.

The I-6s are the Inmarsat’s first hybrid satellites, fitted with both L-band (ELERA) and Ka-band (GlobalXpress) payloads.

The I-6 F1 has double the capacity per beam and double the power of the previous Inmarsat-4 generation of L-band satellites which means that much more data can be carried over the same amount of bandwidth. The beams can also be rerouted to match demand.

“These are the first L-band satellites that we’ve launched since Alphasat in 2013,” commented Mark Dickinson, Inmarsat Deputy CTO.

“The fourth-generation Inmarsat-6s are very complex satellites which use the latest digital processing technology.

There is so much payload in this spacecraft that there isn’t a spare centimetre to put in an additional piece of hardware.

For the first time for Inmarsat, they’re actually a dual-band satellite with two frequency bands – an L-band satellite, which will allow us to support our global L-band network out until the 2040s, plus enhanced Ka-band capacity in the form of steerable beams which can be moved about to where our needs are most.”

“We can adjust beams where we need to which gives us the ultimate flexibility in providing services to customers,” added Edwina Paisley, I-6 Programme Manager.

“Inmarsat 6 is, by far, the most complex telecommunications spacecraft ever launched. It therefore needed a test campaign of equal complexity to ensure that there is 100% mission success.”

These include vibration tests which exceed those which would be experienced during the launch. These is also an extensive electrical and payload testing to ensure that the payload performs at its absolute optimum.”

“The Inmarsat-6 have 50% more spectrum and double the amount of processing power and double the amount of power that we can transmit and thus we can get easily four times the amount of capacity through the network as we do today,” said Inmarsat CTO Peter Hadinger.

“They will act as a continuation of Inmarsat’s commitment to our customers to continue providing a global L-band network to ensure the safety of both the aviation and maritime industries until the 2040s.”

I-6 uses

Inmarsat believes that enhanced capabilities of the new satellites will both ‘future-proof’ its existing ELERA and Global Xpress services, as well as providing a ‘springboard for innovation’ for new emerging technologies.

These include continued maritime and aviation safety, mobile connectivity for military and first responder networks, ISR operations, inter space communications, autonomous transport, ocean monitoring and Internet of Things (IoT) innovation for agriculture, electrical utilities, mining, oil, gas transport and logistics applications.

Inmarsat ORCHESTRA logo.

The launch of I-6 F1 will be followed by six further launches, so that seven global high capacity satellites will be in orbit by 2024, together with an expansion of the ground network.

In addition to I-6 F2 in 2022, three more Global Xpress satellites, GX7, 8 and 9, are due to be launched from 2023 which will employ dynamic beam forming to simultaneously create thousands of reconfigurable independent beams of different sizes, bandwidth and power.

Two HEO (highly elliptical orbit) payloads, GX10A and 10B, will offer mobile broadband connectivity over the Arctic region.

Another eight ground sites are to be commissioned by 2022 to support further regional connectivity expansion and the new Inmarsat-6 satellites.

Introducing the ORCHESTRA

Inmarsat has announced plans to combine its ELERA (L-band) and Global Xpress (Ka-band) networks with geosynchronous orbit (GEO), targeted low Earth orbit (LEO) and highly elliptical orbit (HEO) satellites which, together with terrestrial 5G services, will create a ‘global, multi-dimensional, dynamic mesh connectivity’ solution named ORCHESTRA. “An orchestra brings different instruments together, each supporting the other and playing its role in the masterpiece,” said Inmarsat CEO, Rajeev Suri. “We’re building ORCHESTRA on the same concept.”

According to Inmarsat, ORCHESTRA will provide a layered approach combining the following capabilities:

ELERA: provides a critical layer of always-on connectivity with all-weather resilience.
Global Xpress: delivers reliable, high-speed, global coverage with security and full redundancy.
Terrestrial 5G: adds ultra-high capacity at specific high demand hotspots, such as busy ports, airports, straits and sea canals.
LEO: a small, targeted constellation of 150-175 satellites, layering additional high capacity over further high-demand areas.

These layers will be supplemented by a ‘dynamic mesh network’ which will allow individual terminals to act as nodes to route traffic to and from other terminals, enabling the extension of direct links previously out of range, such as ships beyond the reach of 5G.

Inmarsat-3 F5 satellite.

On 16 December Inmarsat announced that ORCHESTRA had achieved its first milestone with the successful activation of a low Earth orbit (LEO) satellite payload to test new concepts and system configurations for ORCHESTRA’s proposed LEO constellation to deliver global communications for mobility and government customers.

By drawing on the unique capabilities of each component, says the company, ORCHESTRA will enable enhanced connectivity while eliminating such longstanding issues, such as congestion at high demand hotspots, like busy ports, airports, sea canals and flight corridors.

Inmarsat believes that ORCHESTRA could be used for next-generation service capabilities, such as air traffic management for urban air mobility networks, IoT systems, operational connectivity for ferries and cruise ships and tactical private networks to connect international aid, forces or government agencies in the field while securely relaying critical data home for analysis.

Satnav signal

In addition to launching new satellites, Inmarsat is also finding new uses for ones already in orbit.

On 7 December the company announced that it was testing the ability of its Inmarsat-3 F5 satellite to deliver a UK-generated satellite navigation (satnav) signal, to replace the capabilities lost after Brexit when UK no longer has access to the European Geostationary Navigation Overlay Service (EGNOS) Safety of Life services and its involvement in the EU’s Galileo programme.

Developed in partnership with the European Space Agency, Goonhilly Earth Station and GMVNSL, the UK Space-Based Augmentation System (UKSBAS) test project repurposes a transponder from the I-3 F5, launched in 1998, to provide an overlay signal to augment the US Global Positioning System satellite navigation system. Following the trials, the first signal-in-space is scheduled to be generated by March 2022.