. A second TDMA system as tively. However, in general the take up of these planned assignments used for signalling and order wire purposes to control both tele- has been slow. The specified power flux density requires satellite phone and telex facilities. transmitter output powers of several hundreds of watts for the larger A second generation of INMARSAT satellites is in the process of countries, which causes capital costs to be high and it is arguable deployment, replacing the various satellites that brought the system that recent advances in the design of low cost satellite broadcasting into being (Berlin, 1986). These satellites operate in the same receivers has made such a high power flux density unnecessary. frequency bands as did their predecessors but the transponder band- Furthermore, the limiting of coverage to national boundaries is no width has been increased to 16MHz and the available down-link longer attractive in, for example, Western Europe. The general power is also considerably increased. public is tending to get its satellite broadcasting signals from other With the additional capacity that the second generation of satel- sources. lites will bring to the INMARSAT system, it will be possible to Many satellites of the fixed satellite service, in particular domestic provide for growth of maritime use but it also becomes possible to systems of the USA, are used to distribute substantial numbers of consider opening up new services. In 1987 the INMARSAT Con- TV programme channels to terrestrial radio stations, cable network vention was amended to permit the organisation to offer service to head ends, hotels and so on. However, members of the public also aircraft and a start has been made in offering connections to the set up domestic antennas to receive these transmissions for their public telephone network to passengers on some aircraft on trans- own enjoyment. This process has spread, for example, to Europe, Atlantic flights. INMARSAT is also offering telex service to road and account has now been 