Twenty years ago, most of the Western world's satellites were lifted into orbit by American rockets. Today, this dominant position has been taken over by the European Ariane 4, but competition is once again hotting up. Hence the tremendous significance of next week's maiden flight.
The Ariane 5 programme dates back to 1985 when the European Space Agency's ministerial council - without the backing of the UK government - gave the go-ahead to preliminary studies for a new rocket which would meet predicted demand for the late 1990s and lead Europe into the 21st century ahead of its competitors.
Since then, between 6,000 and 10,000 employees at 150 European companies - mainly in France, Germany and Italy - have been working full-time on the new launcher. Belatedly recognising its mistake in virtually ignoring one of the most commercially viable space projects in Europe, the UK government has recently agreed to contribute the modest sum of $4.3m to the programme over the next four years - "Enough to get the flag on the side of the rocket," said one disillusioned commentator.
Ariane 5's main task will be to carry large communications satellites into geostationary orbit above the equator. Officials of the European Space Agency, which paid for its development, and of Arianespace, the private company that operates and markets the rockets, believe size will be a major factor in meeting this requirement.
Standing more than 50m tall and weighing 750 tonnes at lift-off, the newcomer will be able to carry nearly 20 tonnes into low Earth orbit. However, on most missions it will be required to lift one communications satellite weighing 6.8 tonnes or two with a total mass of 5.9 tonnes into geostationary orbit 36,000km above the equator.
Most of the awesome power required to carry such heavy payloads comes from two solid-fuel rocket boosters which stand like stilts on either side of the rocket. Standing 30m tall, they are 10 times larger than any solid-fuel motors previously made in Europe.
Just as important is the newly developed first-stage Vulcain rocket motor, mainly built by France and Germany. Burning 1 tonne of supercooled liquid hydrogen and oxygen every four seconds, this engine will propel payloads to a height of 140km before a much smaller German-built second-stage motor completes the final insertion into orbit.
Investment in the new system has not been limited to the rocket. $1.3bn has been ploughed into building additional facilities at the Kourou spaceport in French Guiana. They include a brand new launch pad, buildings for integration and final assembly of the rocket and its payload, a plant for manufacturing solid fuel, a solid booster testing area and a plant for production of liquid fuel.
With the end of the Cold War, the market for launch services has recently been opened to competitors from the East in addition to the traditional US competition. While the threat from China's Long March rockets has been dented by a series of mishaps, including the deaths of at least six people during a launch explosion in February, a recent alliance between the Russians and the American aerospace giant Lockheed-Martin Corporation has introduced a major new player.
Since it has been on offer in the West, the Russian Proton rocket has earned orders for 16 launches over the next few years. With an enviable record for reliability over three decades, a highly competitive price and performance even better than Ariane 5's, the Proton is likely to be the major threat to European dominance in the coming years.
ESA's programme manager, Jacques Durand, is confident that the new booster will be able to fight off its rivals. "Back in 1987, we had a number of objectives. First, to increase performance. This now appears right because the mass of satellites has increased. Then we had the objective of making it even more reliable than Ariane 4. This is very important in international competition and attracts customers' interest. Thirdly, in the production phase, Ariane 5 will be 10 per cent less costly than Ariane 4. All of these factors will place Europe in a good position to face the competition."
The newcomer's first two launches are regarded as test flights. On its maiden flight, Ariane 5 will be carrying four identical science satellites, known as Cluster. Together with the recently launched SOHO satellite, they will make up ESA's contribution to the International Solar-Terrestrial Science Programme.
Flying in formation above the Earth's poles, Cluster will study how charged particles ejected by the Sun interact with the Earth's magnetic field.
For Ariane 5's second flight in October, ESA is offering a cut-price launch of a commercial satellite. Also on board will be an amateur communications satellite and a mock-up of a re-entry capsule which will carry the agency's hopes of one day developing a manned spacecraft.
ESA still intends to play a significant role in the $30bn project to assemble a giant international space station between 1997 and 2002. This includes using Ariane 5 to deliver an automated cargo vehicle to the station.
Meanwhile, ESA is already working towards a still more powerful version of Ariane 5. By the year 2003, the agency will have spent a further $2.6bn on uprating the rocket so that it will be capable of lifting 7.4 tonnes into orbit. "It should be operating for at least another 20 years," says Jacques Durand. "After 2003 we will be carrying out parallel work on a reusable launcher and further evolution of Ariane 5."Reuse content