Convention on the International Maritime Satellite Organization

Adoption: 3 September 1976; Entry into force: 16 July 1979

The Convention on the International Maritime Satellite Organization was adopted by IMO in 1976 to establish and oversee satellite communications for shipping.

Under the treaty, the International Mobile Satellite Organization (IMSO) has been established as the inter-governmental body that oversees the provision of certain satellite-based maritime distress communication services, specifically those used in the Global Maritime Distress and Safety System (GMDSS).

IMO is currently reviewing the GMDSS, to modernize it and bring it up to date. 

International Mobile Satellite Organization (IMSO)
IMSO is headquartered in London and has more than 100 Member States.

As well as overseeing satellite communications under the GMDSS, IMSO has also been appointed by IMO to audit and review the performance of the international system for the Long Range Identification and Tracking of Ships (LRIT).

Recognition of providers of mobile satellite communications systems in the GMDSS
IMO has adopted Criteria for the Provision of Mobile Satellite Communication Systems in the GMDSS (Resolution A.1001(25)).

This sets out the criteria and process for evaluating mobile satellite communication systems that might have the potential to offer maritime distress and safety communications within the GMDSS. 

Recognition of a mobile satellite communication system for use in the GMDSS would be given by IMO’s Maritime Safety Committee (MSC).

Recognised mobile satellite communication systems
IMO has recognised Inmarsat and Iridium to provide satellite communication systems for use in the GMDSS.

Soon after the launch of the world's first telecommunications satellite, Telstar, in 1962, IMO recognised the potential for satellite communications to assist in distress situations at sea and initiated a study of the operational requirements for a satellite communications system devoted to maritime purposes.

In 1973, IMO decided to convene a conference to establish a new maritime communications system based on satellite technology. This conference first met in 1975 and held three sessions, at the third of which, in 1976, the Convention on the International Maritime Satellite Organization (then called Inmarsat) was adopted, together with an Operating Agreement.
The Convention defined the purposes of the International Maritime Satellite Organization as being to improve maritime communications, thereby assisting in improving distress and safety of life at sea communications, the efficiency and management of ships, maritime public correspondence services, and radiodetermination capabilities.
The Operating Agreement set an initial capital ceiling for the Organization. Investment shares were determined, proportionate to utilization of the Inmarsat space segment. Inmarsat, headquartered in London, began operations in 1982.
Inmarsat's obligation to provide maritime distress and safety services via satellite were enshrined within the 1988 amendments to SOLAS which introduced the GMDSS. Ships sailing in specified sea areas were required to carry Inmarsat communications equipment for distress and safety calls and to receive navigational warnings.
IMSO oversight body and commercial Inmarsat created
In 1994, the name of the Organization was changed to the International Mobile Satellite Organization, then abbreviated to Inmarsat. This reflected the extension of its services from the maritime sector to other modes of transport.
In 1998, Inmarsat member Governments agreed to privatize Inmarsat, from April 1999. The new structure comprised two entities: 

• Inmarsat Ltd - a public limited company which forms the commercial arm of Inmarsat. The company has taken on all the commercial activities of Inmarsat and is regulated by British law. It was completely privatised by the end of 2003.

• International Mobile Satellite Organization (IMSO) - the intergovernmental body established to provide oversight of certain public satellite safety and security communication services provided by mobile satellite communication systems. IMSO is an observer at IMO meetings.