INMARSAT is a British satellite operator offering global mobile satellite communication services. It provides telephone and data services with worldwide coverage via portable and mobile terminals using various ground stations through 11 geostationary satellites. The International Maritime Organization (IMO) set up INMARSAT in 1979.

INMARSAT's satellite network provides communications services to governments, aid agencies, media organizations and businesses with a need to communicate in remote regions or where there is no reliable terrestrial network. The company is headquartered in London, UK and listed on the London Stock Exchange.


The company originates from the International Maritime Satellite Organization (INMARSAT), a non-profit intergovernmental organization established in 1979 and requested by the International Maritime Organization (IMO). The IMO was the UN maritime body and pursuant to the Convention on the International Maritime Satellite Organization, signed by 28 countries in 1976. The organization was created to establish and operate a satellite communications network for the maritime community. In coordination with the International Civil Aviation Organization in the 1980’s, the convention governing INMARSAT was amended to include improvements to aeronautical communications, notably for public safety. The member states owned varying shares of the operational business.


In the 90’s, many member states were unwilling to invest in improvements to INMARSAT's network, especially owing to the competitive nature of the satellite communications industry, while many recognized the need to maintain the organization's older systems and the need for an intergovernmental organization to oversee public safety aspects of satellite communication networks. In 1998 an agreement was reached to modify INMASAT's mission as an intergovernmental organization and separate and privatize the organization's operational business, with public safety obligations attached to the sale.

In April 1999, INMARSAT succeeded by the International Mobile Satellite Organization (IMSO) as an intergovernmental regulatory body for satellite communications, while Inmarsat's operational unit was separated and became the UK-based company Inmarsat Ltd. The IMSO and Inmarsat Ltd. signed an agreement imposing public safety obligations on the new company. INMARSAT was the first international satellite organization that was privatized.

In 2005 Apax Partners and Permira bought shares in the company. The company was also first listed on the London Stock Exchange in the same year. In March 2008 it was disclosed that U.S. hedge fund Harbinger Capital owned 28% of the company. In 2009, Inmarsat completed the acquisition of satellite communications provider Stratos Global Corporation (Stratos) and acquired a 19% stake in SkyWave Mobile Communications Inc., a provider of INMARSAT D+/IsatM2M network services that in turn purchased the GlobalWave business from TransCore. Inmarsat won the 2010 MacRobert Award for its Broadband Global Area Network (BGAN) service.

In 2018 US based satellite operator EchoStar unsuccessfully made two attempts to take over INMARSAT but both bids that reached 3.2billion USD were rejected by the company.

In January 2019 a consortium of private equity funds, Apax Partners in the USA, Warburg Pincus International based in UK and Canada Pension PlanInvestment Board (CPPIB) agreed to acquire Inmarsat in a 3.4billion USD deal. The consortium disclosed the proposal for the takeover in March 2019. Lansdowne Partners, INMARSAT’s largest stakeholderowning 11.4% of the company, backed the deal.

The consortium believes that INMARSAT is well positioned for growth based on its global infrastructure, technological and capacity roadmaps, and strong spectrum holdings. In particular, the companies believe that Inmarsat’s business model is characterized by predictable revenues from a range of long-term contracts with governments and other financially secure customers. Most notably, the consortium sees strong potential for Inmarsat’s In Flight Connectivity (IFC) business in commercial aviation and in seeking to maximize global Internet of Things (IOT). 

Operations & satellite coverage

INMARSAT provides also a global maritime distress and safety service (GMDSS) to ships and aircraft at no charge.

Services include traditional voice calls, low-level data tracking systems, and high-speed Internet and other data services as well as distress and safety services. The most recent of these provides GPRS-type services at up to 492 kbit/s via the Broadband Global Area Network (BGAN) IP satellite modem the size of a notebook computer. Other services provide mobile Integrated Services Digital Network (ISDN) services used by the media for live reporting on world events via videophone.

The first (F1) and second (F2) of Inmarsat's series of satellites, known as the "I4" satellites, were launched in June and November 2005. The third and final satellite (F3) was launched from the Baikonur Cosmodrome in Kazakhstan on the August 18th, 2008.

Upcoming projects

Global Xpress

In August 2010 INMARSAT awarded Boeing a contract to build a constellation of three Inmarsat-5 satellites, as part of a 1.2 billion USD worldwide wireless broadband network called Inmarsat Global Xpress. The three Inmarsat-5 (I-5) satellites will be based on Boeing's 702HP spacecraft platform. The first (Inmarsat-5F1) was launched on December 8th, 2013. The second Inmarsat-5 satellite was launched in February 2015 and the third in August 2015.

The satellites will operate at Ka-band (20–30 GHz). Each Inmarsat-5 will carry a payload of 89 small Ka-band beams which combined will offer global Ka-band spot coverage. In addition each satellite will carry six fully steerable beams that can be pointed at commercial or government traffic hotspots. According to Inmarsat, Global Xpress will deliver download speeds in excess of 60Mbit/s to a 60 cm dish.

INMARSAT has announced plans to offer high-speed in-flight broadband internet on airplanes using a system that integrates the use of Global Xpress and S-band service by using two antennas, the GX antenna on top of the plane for satellite backhaul over Ka-band frequencies and a S-band antenna underneath for backhaul from ground stations.

In February 2011 INMARSAT announced that iDirect had been awarded the contract to provide both the ground segment and the 'core module' that provides the key electronics in the new Global Xpress (GX) maritime terminals.

Inmarsat's foray into S-band, mobile services

On 30 June 2008, the European Parliament and the Council adopted the European’s Decision to establish a single selection and authorization process (ESAP – European S-band Application Process) to ensure a coordinated introduction of mobile satellite services (MSS) in Europe. The selection process was launched in August 2008 and attracted four applications by prospective operators (ICO, Inmarsat, Solaris Mobile (now EchoStar Mobile) and TerreStar).

In May 2009, the European Commission selected two operators, Inmarsat Ventures and Solaris Mobile, giving these operators “the right to use the specific radio frequencies identified in the Commission's decision and the right to operate their respective mobile satellite systems". EU Member States now have to ensure that the two operators have the right to use the specific radio frequencies identified in the Commission's decision and the right to operate their respective mobile satellite systems for 18 years from the selection decision. The operators are compelled to start operations within 24 months from the selection decision.


INMARSAT's S-band satellite program, called EuropaSat, will provide mobile broadcast and 2-way telecommunications services and next-generation MSS services across all 27 member states. It is being built by Thales Alenia Space since its strong in-house experience and long heritage in S-band. The satellite is scheduled for launch in 2016. The agreement was signed in August 2008 and has been put on hold in late 2009. INMARSAT instead plans to seek external investors to fund the project, and ultimately to spin it off as a separate company. In 2014, the project was revived as a joint project with ArabSat, which will be named EuropaSat / HellasSat-3.

AlphaSat for extended L-band services

The AlphaSat I-XL satellite, built by EADS Astrium, was launched on 25 July 2013, AlphaSat I-XL by an Ariane 5ECA rocket from the Kourou launch base in French Guyana. The new-generation AlphaSat I-XL will be positioned at 25° E to offer advanced mobile voice and data communications services across Europe, Africa and the Middle East using L-Band. It features a new generation digital signal processor for the payload, an 11m aperture AstroMesh antenna reflector, supplied by Astro Aerospace in Carpenteria, CA.

In addition, AlphaSat will host four ESA-provided technology demonstration payloads: an advanced star tracker using active pixel technology, an optical laser terminal for geostationary to low-Earth orbit communication at high data rates, a dedicated payload for the characterization of transmission performance in the Q-V band in preparation for possible commercial exploitation of these frequencies and a radiation sensor to better characterize the environment at geostationary orbit.

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References:  edition March 25th 2019