This article is about the satellite telecommunications company. For the intergovernmental organization formerly known as INMARSAT, see International Mobile Satellite Organization.
Inmarsat plc
Public company
Traded as LSE: ISAT
Industry Satellite communication
Founded 1979 (1979)
Headquarters London, England, UK
Key people
Andrew Sukawaty (Chairman); Rupert Pearce (CEO)
Revenue US$1,274.1 million (2015)[1]
US$426.4 million (2015)[1]
US$282.0 million (2015)[1]
Inmarsat-3 satellite
Inmarsat satellite telephone in use after a natural disaster in Nias, Indonesia. The unit depicted was manufactured by Thrane & Thrane A/S of Denmark. (April 2005)

Inmarsat plc (LSE: ISAT) is a British satellite telecommunications company, offering global mobile services. It provides telephone and data services to users worldwide, via portable or mobile terminals which communicate with ground stations through twelve geostationary telecommunications satellites. Inmarsat's network provides communications services to a range of governments, aid agencies, media outlets and businesses with a need to communicate in remote regions or where there is no reliable terrestrial network. The company is listed on the London Stock Exchange, is a constituent of the FTSE 250 Index and a financial (as well as technical) sponsor of Télécoms Sans Frontières.



The present company originates from the International Maritime Satellite Organization (INMARSAT), a non-profit intergovernmental organization established in 1979 at the behest of the International Maritime Organization (IMO)—the United Nations' maritime body—and pursuant to the Convention on the International Maritime Satellite Organization, signed by 28 countries in 1976.[2][3] The organisation was created to establish and operate a satellite communications network for the maritime community.[2][4] In coordination with the International Civil Aviation Organization in the 1980s, the convention governing INMARSAT was amended to include improvements to aeronautical communications, notably for public safety.[2] The member states owned varying shares of the operational business.[3] The main offices were originally located in the Euston Tower, Euston Road, London.[5]


In the mid-1990s, 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.[3] In 1998, an agreement was reached to modify INMARSAT's mission as an intergovernmental organization and separate and privatize the organization's operational business, with public safety obligations attached to the sale.[3]

In April 1999, INMARSAT was 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.[2][6] The IMSO and Inmarsat Ltd. signed an agreement imposing public safety obligations on the new company.[2] Inmarsat was the first international satellite organization that was privatized.[3]

In 2005, Apax Partners and Permira bought shares in the company. The company was also first listed on the London Stock Exchange in that year.[7] In March 2008, it was disclosed that U.S. hedge fund Harbinger Capital owned 28% of the company.[8] In 2009, Inmarsat completed the acquisition of satellite communications provider Stratos Global Corporation (Stratos)[9] and acquired a 19-percent stake in SkyWave Mobile Communications Inc., a provider of Inmarsat D+/IsatM2M network services which in turn purchased the GlobalWave business from TransCore.[10] Inmarsat won the 2010 MacRobert Award for its Broadband Global Area Network (BGAN) service.[11][12]

Malaysia Airlines Flight 370

In March 2014, Malaysia Airlines Flight 370 disappeared with 239 passengers and crew en route from Kuala Lumpur to Beijing. After turning away from its planned path and disappearing from radar coverage, the aircraft's satellite data unit remained in contact with Inmarsat's ground station in Perth via the IOR satellite. The aircraft used Inmarsat's Classic Aero service, which does not provide explicit information about the aircraft's location. Analysis of these communications by Inmarsat and independently by other agencies determined that the aircraft flew into the southern Indian Ocean and was used to guide the search for the aircraft.[13][14]


The Inmarsat head office is at Old Street Roundabout in the London Borough of Islington.[15]

Aside from its commercial services, Inmarsat provides global maritime distress and safety services (GMDSS) to ships and aircraft at no charge, as a public service.[16]

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.[17] Other services provide mobile Integrated Services Digital Network (ISDN) services used by the media for live reporting on world events via videophone.[18]

The price of a call via Inmarsat has now dropped to a level where they are comparable to, and in many cases lower than, international roaming costs, or hotel phone calls. Voice call charges are the same for any location in the world where the service is used. Tariffs for calls to Inmarsat country codes vary, depending on the country in which they are placed. Inmarsat primarily uses country code 870 (see below).[19]

Newer Inmarsat services use an IP technology that features an always-on capability where the users are only charged for the amount of data they send and receive, rather than the length of time they are connected.[20]

The first (F1) and second (F2) of Inmarsat's most recent 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 18 August 2008.[21]

In addition to its own satellites, Inmarsat has a collaboration agreement with ACeS regarding handheld voice services.[22]


Inmarsat Global HQ at 99 City Road, London. (January 2006)

There are three types of coverage related to each Inmarsat I-4 satellite.[23]

Global beam coverage
Each satellite is equipped with a single global beam that covers up to one-third of the Earth's surface, apart from the poles. Overall, global beam coverage extends from latitudes of −82 to +82 degrees regardless of longitude.
Regional spot beam coverage
Each regional beam covers a fraction of the area covered by a global beam, but collectively all of the regional beams offer virtually the same coverage as the global beams. Use of regional beams allow user terminals (also called mobile earth stations) to operate with significantly smaller antennas. Regional beams were introduced with the I-3 satellites. Each I-3 satellite provides four to six spot beams; each I-4 satellite provides 19 regional beams.
Narrow spot beam coverage
Narrow beams are offered by the three Inmarsat-4 satellites. Narrow beams vary in size, tend to be several hundred kilometers across. The narrow beams, while much smaller than the global or regional beams, are far more numerous and hence offer the same global coverage. Narrow spot beams allow yet smaller antennas and much higher data rates. They form the backbone of Inmarsat's handheld (GSPS) and broadband services (BGAN). This coverage was introduced with the I-4 satellites. Each I-4 satellite provides around 200 narrow spot beams.


Satellite Coverage Longitude


Vehicles Launch date (GMT) Services / notes
Marisat series
Marisat F1 Delta 2914 19 February 1976
Marisat F2 Delta 2914 14 October 1976 Transferred to Intelsat in 2004, decommissioned in 2008
Marisat F3 Delta 2914 10 June 1976
MARECS series
MARECS-1 Ariane 1 20 December 1981
MARECS-B - Ariane 1 9 September 1982 Launch failure
MARECS-2 Ariane 3 10 November 1984
Inmarsat-2 series
Inmarsat-2 F1 Delta II 6925 30 October 1990 Decommissioned 19 April 2013
Previous record holder for mission lifespan[25]
Inmarsat-2 F2 POR 143° east Delta II 6925 8 March 1991 Decommissioned Dec 2014
World record for mission lifespan[25]
Inmarsat-2 F3 Ariane 44L 16 December 1991 Decommissioned 2006
Inmarsat-2 F4 Ariane 44L 15 April 1992 Decommissioned 2012
Inmarsat-3 series
Inmarsat-3 F1 IOR 64.5° east Atlas IIA 3 April 1996 Existing and evolved services only
Inmarsat-3 F2 AOR-E 15.5° west Proton-K/DM1 6 September 1996 Existing and evolved services only
Inmarsat-3 F3 POR 178.2° east Atlas IIA 18 December 1996 Existing and evolved services only
Inmarsat-3 F4 AOR-W 54° west Ariane 44L 3 June 1997 Existing and evolved services only
Inmarsat-3 F5 I-3 Europe, Middle-East, Africa 24.6° east Ariane 44LP 4 February 1998 Various leases
Inmarsat-4 series
Inmarsat-4 F1[26] I-4 Asia-Pacific 143.5° east Atlas V 431 11 March 2005 BGAN family, SPS and lease services
Inmarsat-4 F2[27] I-4 Europe, Middle-East, Africa 64.4° east Zenit-3SL 8 November 2005 BGAN family, SPS and lease services

Transferred from 25° east to 63° east in mid-2015[28]

Inmarsat-4 F3[29] I-4 Americas 98° west Proton-M/Briz-M 18 August 2008 BGAN family and lease services
Inmarsat-4A F4[30] I-4 Europe, Middle-East, Africa 24.8° east Ariane 5ECA 25 July 2013 BGAN family, SPS and lease services
Inmarsat-5 series
Inmarsat-5 F1[31][32] I-5 Europe, Middle East, Africa 62.6° east Proton-M/Briz-M 8 December 2013 Ka-Band global data services, Global Xpress
Inmarsat-5 F2[33] I-5 Americas 55° west Proton-M/Briz-M 2 February 2015 Ka-Band global data services, Global Xpress
Inmarsat-5 F3[34] I-5 Pacific, Asia, West Americas 179.6° east Proton-M/Briz-M 28 August 2015 Ka-Band global data services, Global Xpress
Inmarsat-5 F4[35] Falcon Heavy 2017 (planned) Ka-Band global data services, Global Xpress

Country codes

The permanent telephone country code for calling Inmarsat destinations is:[19]

The 870 number is an automatic locator; it is not necessary to know to which satellite the destination Inmarsat terminal is logged-in. SNAC is now usable by all Inmarsat services.

Country codes phased out on 31 December 2008 were

The other four country codes corresponded to the areas that Inmarsat satellites cover (normally one satellite per area). These areas were commonly called "Ocean Regions". With the advent of SNAC on 870, the older country codes were no longer needed. They were formally phased out on 31 December 2008 but may still be routed by some regional carriers.


Inmarsat-3 satellite locations

Inmarsat has developed a series of networks providing certain sets of services (most networks support multiple services). They are grouped into two sets, existing and evolved services, and advanced services. Existing and evolved services are offered through land earth stations which are not owned nor operated by Inmarsat, but through companies which have a commercial agreement with Inmarsat. Advanced services are provided via distribution partners but the satellite gateways are owned and operated by Inmarsat directly.

Advanced services

The "BGAN Family" is a set of IP-based shared-carrier services, as follows:[36]

M2M communications

The "BGAN M2M Family" is a set of IP-based services designed for long-term machine-to-machine management of fixed assets, as follows:[37]

Global voice services

The company offers portable and fixed phone services as follows:[38]

Existing and evolved services

They are based on older technologies, as follows:[39]

New projects underway

Global Xpress

In August 2010, Inmarsat awarded Boeing a contract to build a constellation of three Inmarsat-5 satellites, as part of a US$1.2 billion 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 5-F1) was launched in December 2013, entering commercial service on 1 July 2014, the second was launched in February 2015 and the third in August 2015.[41] The satellites will operate at Ka-band in the range of 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.[42] According to Inmarsat, Global Xpress will deliver download speeds in excess of 60 Mbit/s to a 60 cm dish.[42]

Inmarsat has announced plans to offer high-speed in-flight broadband internet on airliners using a system that integrates the use of Global Xpress and S-band service by using two antennas,[43] the GX antenna on top of the plane for satellite backhaul over Ka band frequencies and an S band antenna underneath for backhaul from ground stations.[44]

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.[45]

During the course of 2016, Inmarsat will be introducing a series of market-specific, high-speed connectivity services powered by Global Xpress.

EuropaSat, 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 authorisation 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), TerreStar).[46][47]

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 (May 2011) from the selection decision.[48][49][50][51]

Inmarsat's S-band satellite programme, called EuropaSat, will deliver mobile multimedia broadcast, mobile two-way broadband telecommunications and next-generation MSS services across all member states of the European Union and as far east as Moscow and Ankara by means of a hybrid satellite/terrestrial network. It is being built by Thales Alenia Space and is slated for launch in 2016.[52]

Alphasat for extended L-band services

Main article: Alphasat

Launched on 25 July 2013, Alphasat I-XL was carried into orbit by an Ariane 5 ECA rocket from the Guiana Space Centre, Europe’s spaceport in Kourou, French Guiana.[53] The satellite was built by Astrium using an Alphabus platform and weighed more than six tons at launch. The new-generation Alphasat I-XL will be positioned at 25 degrees East 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 11-meter aperture AstroMesh antenna reflector, supplied by Astro Aerospace in Carpenteria, CA.[54] Its design life is 15 years.[55]

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 characterise the environment at geostationary orbit.[54]


INMARSAT and Iridium frequency bands abut each other at 1626.5 MHz thus each satcom radio has the ability to interfere with the other. Usually, the far more powerful INMARSAT radio disrupts the Iridium radio up to 10–800 metres away.[56]

See also


  1. 1 2 3 "Preliminary Results 2015" (PDF). Retrieved 25 March 2016.
  2. 1 2 3 4 5 Proposed Amendments to the Convention on the International Mobile Satellite Organization (IMSO), International Civil Aviation Organization, 14 May 2003, archived from the original on 7 June 2011
  3. 1 2 3 4 5 Sagar, David (1999). Harris, R. A., ed. "The privatisation of INMARSAT: Special problems". International Organisations and Space Law, Proceedings of the Third ECSL Colloquium, Perugia, Italy, 6–7 May 1999: 127–142. Bibcode:1999ESASP.442..127S.
  4. Jonathan Higgins, "Satellite Newsgathering", Focal Press, 2007, page 204 ISBN 978-0-240-51973-9
  5. Godwin, Matthew (5 December 2007). "Interview with Roy Gibson" (PDF). Oral History of Europe in Space. European Space Agency. p. 5. Retrieved 1 June 2016.
  6. Jonathan Higgins page 207
  7. "Dollars & Sense". 2 January 2006. Retrieved 18 April 2011.
  8. "Private equity orbits Inmarsat". 7 March 2008. Retrieved 18 April 2011.
  9. "Inmarsat buys Stratos Global". Washington Business Journal. 16 April 2009. Retrieved 28 March 2015.
  10. SkyWave and partners wrap up three-part deal Archived 1 February 2016 at the Wayback Machine.
  11. "Inmarsat grabs the MacRobert engineering prize". 8 June 2010. Retrieved 8 June 2010.
  12. "Making things better – finalists announced for Britain's top engineering award". BBC News. 10 May 2010. Retrieved 8 June 2010.
  13. "UK firm behind Malaysia Airlines flight MH370 breakthrough". BBC News. 24 March 2014.
  14. Ashton, Chris; Bruce, Alan Shuster; Colledge, Gary; Dickinson, Mark (14 September 2014). "The Search for MH370". Journal of Navigation. Royal Institute of Navigation. 68: 1–22. doi:10.1017/S037346331400068X. Lay summary.
  15. "Privacy Policy." Immarsat. Retrieved on March 26, 2014. "99 City Road London EC1Y 1AX United Kingdom"
  16. "GMDSS weather". Retrieved 18 April 2011.
  17. "BGAN terminals". Inmarsat. Retrieved 18 April 2011.
  18. "Transforming satellite newsgathering" (PDF). Retrieved 18 April 2011.
  19. 1 2 "one world, one number". Inmarsat. Retrieved 18 April 2011.
  20. "BGAN provides "eyes and ears" for oil rigs" (PDF). Retrieved 18 April 2011.
  21. "Successful launch for third Inmarsat-4 satellite". Retrieved 18 April 2011.
  22. Inmarsat and ACeS announce low cost hand held and fixed voice services
  23. "How the Inmarsat satellite system works". Retrieved 18 April 2011.
  24. "N2YO". Retrieved 7 December 2015.
  25. 1 2 "Airbus-built Inmarsat 2 F2 Satellite Breaks World Record for Mission Lifespan". Via Satellite. 22 December 2014. Retrieved 1 August 2015.
  26. "Inmarsat-4 f1". National Space Science Data Center.
  27. "All go for giant comms satellite". BBC News. 8 November 2005. Retrieved 18 April 2011.
  28. Caleb, Henry (10 June 2015). "Inmarsat-4 F2 Satellite Relocating to Cover Middle East and Asia". Via Satellite. Retrieved 7 December 2015.
  29. "ILS Proton successfully launches Inmarsat-4 F3 satellite". International Launch Services. 19 August 2008. Archived from the original on 23 September 2008.
  30. "Flawless launch of Alphasat". ESA. July 2013.
  31. "Inmarsat begins Global Xpress roll-out". BBC News. 9 December 2013.
  32. "Inmarsat-5 F1". International Launch Services. 8 December 2013.
  33. "Inmarsat launches second Global Xpress satellite". BBC News. 2 February 2015.
  34. "I-5 F3: the mission". Inmarsat inc. 29 August 2015.
  35. "Inmarsat to purchase fourth Inmarsat-5 satellite from Boeing" (Press Release). Inmarsat. 2013-10-07. Retrieved 2015-03-09.
  36. "Inmarsat services". Retrieved 18 April 2011.
  37. "BGAN M2M". Inmarsat. Retrieved 28 March 2015.
  38. "Voice". Inmarsat. Retrieved 28 March 2015.
  39. "our services at a glance". Inmarsat. Retrieved 18 April 2011.
  40. "Private Financing Gets Lift". Retrieved 18 April 2011.
  41. "I-5 F3: the mission". Inmarsat. 28 August 2015. Retrieved 1 September 2015.
  42. 1 2 Philip Bates (15 June 2012). "Major satellite operators adopt contrasting approaches to next-generation high-throughput capacity". news article. Retrieved 22 July 2012.
  43. "Superfast in-flight connectivity on horizon as Inmarsat reveals $1.2b Ka plan". Retrieved 17 August 2010.
  44. "Inmarsat plans EU-wide 'hybrid' network for plane wi-fi". BBC News. Retrieved 29 March 2015.
  45. "iDirect awarded new contract for Global Xpresss infrastructure.". Retrieved 29 December 2011.
  46. "Commission boost for mobile satellite services paves the way for EU-wide high speed data communications". 22 August 2007. Retrieved 18 April 2011.
  47. "New Satellites for Europe: Commission starts selection procedure for operators of pan-European mobile satellite services". Retrieved 18 April 2011.
  48. "European Commission paves the way for European mobile satellite services" (Press release). European Commission. 14 May 2009.
  49. "Mobile Satellite Services in Europe: Frequently Asked Questions". Retrieved 18 April 2011.
  50. Felix, Bate (14 May 2009). "Inmarsat and Solaris win EU spectrum rights". Reuters. Retrieved 18 April 2011.
  51. "Pan-European numbers and services". Retrieved 18 April 2011.
  52. "EuropaSat / HellasSat 3". Retrieved 25 May 2015.
  53. "Photo report: Ariane 5's successful VA214 mission with Alphasat and INSAT-3D". arianespace. 26 July 2013. Retrieved 29 July 2013.
  54. 1 2 "Alphasat bochure". ESA. Retrieved 29 July 2013.
  55. Contract signed with Astrium to build Alphasat payload
  56. "Inmarsat Interference Information". INmarsat. Retrieved 28 March 2015.
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