Mobile satellite communications are used by the airline, maritime, and shipping industries. Among the key providers of mobile satellite communications services are Inmarsat, Intelsat, and Comsat. All began as government entities but, through global privatization efforts, have become private corporations that compete for market share.

Inmarsat The International Maritime Satellite Organization (Inmarsat) was formed in the late 1970s as a maritime-focused intergovernmental organization. Inmarsat completed its transition to a limited company in 1999 and now serves a broad range of markets.

Today, Inmarsat delivers its solutions— including telex, voice, data, and video transmission—through a global distribution network of approximately 200 distributors and other service providers operating in over 150 countries to end users in the maritime, land, and aeronautical sectors.

At year end 2000, approximately 212,000 terminals were registered to access Inmarsat services. Inmarsat’s primary satellite constellation consists of four Inmarsat-3 satellites in geostationary orbit. Between them, the global beams of the satellites provide overlapping coverage of the whole surface of the earth, apart from the poles. The Inmarsat-3 satellites are backed up by a fifth Inmarsat-3 and four previous-generation Inmarsat-2s, also in geostationary orbit.

A key advantage of the Inmarsat-3s over their predecessors is their ability to generate a number of spot beams as well as single large global beams. Spot beams concentrate extra power in areas of high demand and make it possible to supply standard services to smaller, simpler terminals.

Among Imarsat’s newest services is Swift64, which uses its Global Area Network platform to offer airlines and users of corporate jets the ability to operate an Integrated Services Digital Network (ISDN) connection of up to 64 kbps or a Mobile Packet Data connection using the existing Inmarsat antenna already installed on almost 80 percent of modern long-haul jets, as well as over 1000 corporate jets.

With Swift64, airlines will be able to provide passengers with an ISDN 64-kbps bearer channel that is billed according to connection time. Mobile Packet Data, on the other hand, offers an “always on” connection that is billed according to the number of packets sent. These services enable users to surf the Web and send and receive e-mails and documents across all the continents of the world outside the north and south poles.

Intelsat Another provider on international mobile satellite communications services is Intelsat, which has the widest distribution network of any satellite communications company. Operating since 1964, Intelsat has a global fleet of 21 satellites from which it offers wholesale Internet, broadcast, telephony, and corporate network solutions to leading service providers in more than 200 countries and territories worldwide.

Seven more satellites will be put into operation in the next 2 years to broaden coverage and add capacity. In mid-2001, Intelsat completed its transformation from a treaty-based organization to a privately held company with over 200 shareholders composed of companies from more than 145 countries.

Comsat In the United States, the government-sponsored satellite company was Comsat, which had been the only authorized U.S. organization that could directly access the Intelsat system. Lockheed Martin’s acquisition of Comsat in August 2000 ended the 38-year history of quasi-government backing for Comsat. The federal government created the company in 1962 to prevent AT&T, then a telephone monopoly, from extending its monopoly to the satellite communications sector.

Comsat became a publicly traded company the next year, but Congress ordered that no single investor could own a majority stake in the company because it was the only American firm with access to Intelsat. Congress eliminated the exclusive right to access Intelsat as part of the agreement that allowed Lockheed Martin to purchase Comsat.

Satellites provide a reliable, economical way of providing communications to remote locations and supporting mobile telecommunications. Taking into account the large number of satellites that can be employed, along with their corresponding radiofrequency assignments, it is clear that satellite communications systems offer ample room for expansion.

Conversion of satellite transmissions from analog to digital and use of more sophisticated multiplexing techniques will further increase satellite transmission capacity. Other technological advances are focusing on the higher frequency bands—applying them in ways that decrease signal degradation.