September 7, 1995. Copyright, 1995, Graphic News. All rights reserved FIFTY YEARS OF SATELLITE COMMUNICATION By Nicholas Booth, Science Editor LONDON, September 7, Graphic News- In September 1945, a young engineer who dabbled in science fiction writing came up with a revolutionary idea for communicating around the world. By launching a series of satellites high above the Earth, he suggested, it would be possible for countries on opposite sides of the planet to stay in contact by radio. He submitted his idea to the magazine ÔWireless WorldÕ who published it in September 1945. He used the word Ôspace stationsÕ for he originally thought they would have to be manned to replace the valves which he expected would have to be used. In this, history would record that Arthur Charles Clarke was wrong Ð but the rest of his concept was essentially correct. Today, telecommunications is a multi-billion dollar industry with many satellites in geosynchronous orbit. Arthur C Clarke has wistfully remarked that his only regret is that he didnÕt patent the idea. But his legacy lives on, for the satellites which now orbit high above the EarthÕs equator are located in what is usually termed the Clarke Belt. At the time, Clarke wrote: ÔA true broadcast service giving constant field strength at all times over the whole globe would be invaluable, not to say indispensable, in a world society.Õ But he did suspect that there would be doubting Thomases. ÔMany may consider the solution proposed in this discussion too far-fetched to be taken very seriously,Õ he added. ÔSuch an attitude is unreasonable as everything envisaged here is a logical extension of developments in the last ten years.Õ Fifty years later, we take instantaneous communications for granted. The next generation of telecommunication satellites will be nearer to home and make use of the electronics revolution of the 1990s, involving digital networks and personal computers. Constellations of satellites will criss-cross the skies and beam high speed data all around the globe far faster Ð and cheaper Ð than ever before. The result will be to extend the information superhighway into orbit. THE CONCEPT The Earth completes one rotation Ð its day Ð in just under 24 hours. If a satellite can be launched so that it also completes one orbit in this same time period, it will effectively appear to ÔhoverÕ over the same point. To reach this point in space Ð generally known as a geostationary or geosynchronous orbit Ð it must be launched some 36,000 kilometres above the equator. Once stationed there, these satellites can be tracked without recourse to expensive or complex ground stations. In simple terms, they appear to stay put in the sky! The dawn of the space age saw ClarkeÕs idea come to reality. The first communications satellite to operate from geosynchronous orbit was Syncom 3, launched in 1964 to broadcast TV pictures from the Tokyo Olympics to the U.S. There had been tests of the technology beforehand, most memorably when Telstar beamed the first TV pictures across the Atlantic in July 1962 Ð but not from a geostationary orbit. The following year the International Telecommunications Satellite organisation Ð Intelsat Ð was formed, originally with 13 members. Thirty years later, it now has 133 members and has been joined by other telecommunication organisations operating dedicated services for communicating at sea and in largely uninhabitated areas of the globe. TELECOMMUNICATIONS TODAY Satellite telecommunications today is big business. Voice, data and video networks cover the globe with many thousands of specialised services. As the world becomes ever more voracious in its use of digital information, the importance of these services is also increasing. Mobile faxes, paging and the transmission of electronic mail are becoming an important name of the game. The growth in telecommunications capability is astonishing. Thirty years ago, the first commercial telecommunications satellite operated by Intelsat, Early Bird, could carry 240 telephone calls or one TV channel. The latest generation of Intelsat satellites, Intelsat 7, can carry 90,000 phone calls and four TV channels. In 1970, Intelsat had 4,258 channels in constant use by subscribers around the world: this had ballooned to 121,000 in 1993. According to the United States Department of Commerce, there will be 328 commercially-launched satellites to geostationary orbit over the next fifteen years. That averages at 20 per year, with new generations of satellites replacing older ones which have been superceded by new technology. Each satellite has to be at least two degrees apart from its neighbour, so the maximum number of slots available is 180. At present there are 108 telecommunications satellites in operation, girdling the Clarke Belt high above the equator. THE FUTURE The next steps in telecommunications will focus on smaller, cheaper satellites very much closer to home. To some extent, they will mimic the phenomenally successful Global Positioning Satellites which were first launched by the U.S. military in the 1980s. There are now some 24 satellites orbiting 20,200 kilometres above the globe in a simple network of orbits. Each GPS satellite transmits a navigation beacon which can be read by handheld receivers on the ground. They can work out where the user is on the surface of the Earth to within 10-15 metres: U.S. military personnel can access a coded signal and can find where they are to within three metres. They were supremely useful to U.S. combat soldiers in the Gulf War who were each issued with GPS receivers. The reason why the new generation of telecoms satellites will avoid geostationary orbit is because satellites launched there suffer from a fundamental problem. The further something is from the Earth, the greater the power is needed for transmission. This means that relatively large dishes have to be used to receive signals. This is fine for direct TV broadcasting, but for individual personal computer users, the price becomes too prohibitive. And that is expected to be the growth area. Gains in computer and microchip technology will allow compact handsets with smart antennae to receive and transmit signals from a network of small satellites in low Earth orbit. Motorola has developed its Iridium system which will involve 66 satellites orbiting some 483 miles above the Earth. They will allow digital phone use in countries which do not have the capacity on the ground and could thus be accessed in times of emergency. A similar system, Globalstar, proposed by Loral in the U.S. would use 48 satellites and has a number of technical advantages. Motorola has, however, raised $1 billion of its $3.4 billion and is more likely to be launched by both systemÕs target date of 1998. But looming on the horizon, both literally and figuratively, is the Teledesic concept proposed by cellular phone magnate Craig McCaw and the ubiquitous Bill Gates of Microsoft. It is by far the most impressive Ð and at a cost of $9 billion, by far the most expensive. Over a three year period starting in 1998, 840 satellites the size of personal computers will be launched some 735 miles above the Earth. Through a complex system of routing, users on the ground will be able to communicate with each other at the touch of a button. Teledesic is specifically designed with the aims of the computer and e-mail market in mind and may well corner the market early in the next century. Not to be outdone, however, Hughes in the U.S. have proposed a Spaceway system involving a pair of large satellites, to be placed into geostationary orbit. At a cost of $660 million, it is clear that Arthur C ClarkeÕs dream is very much alive and a little bit cheaper than its supposed successors. MILESTONES 1945: ClarkeÕs paper appears in ÔWireless WorldÕ 1952: Clarke outlines their uses in his book ÔThe Promise Of SpaceÕ 1957: Sputnik 1, the worldÕs first satellite launched 1960: Echo 1, the first ever communications satellite launched. It is essentially a giant balloon and reflects signals passively 1962: Telstar launched and transmits between UK and U.S. when in range 1964: Syncom 1 launched and transmits from Clarke Belt 1965: Intelsat, the worldÕs first international telecommunications agency created. Now has 133 members 1971: Intersputnik formed for Eastern Bloc countries. Now includes Syria and Germany, with total number of 18 members 1976: Arabsat formed for countries in Middle East 1982: Inmarsat formed for International Maritime Communications 1983: Eutelsat takes over from European Space Agency to manage European telecommunications 1990: Motorola announces its Iridium proposal 1993: Hughes proposes the Spaceway system 1994: Teledesic proposal unveiled Sources: Aviation Week, Teledesic Corporation, Intelsat, JaneÕs