PARIS, France -- The European Space Agency (ESA) and the French Space Agency (CNES) have successfully tested an upgraded version of the Ariane 5 solid-fuel rocket booster in French Guiana. This technical improvement program promises to increase the heavy launcher's capability while reducing production costs.

"The results of the burn were exceptional," said Jean-Pierre Ledey, CEO of Europropulsion, the prime contractor that developed and builds the Ariane 5 boosters. With the enhancement of the booster, "we will be able to gain 200 kilograms (440 pounds) of payload in Ariane 5 lift capability for geostationary orbit," said Ledey. Ariane 5 will fly with this upgrade in 2002. But it marks only the first step in a longer upgrade program.

Upgrades are essential for keeping the Ariane 5 a leader in the world satellite launch market. Currently, Ariane 5 can lift 5.9 tons into geostationary orbit. By 2003, thanks to a variety of ambitious upgrading programs, called Ariane Plus and Ariane Evolution, capacity should reach 10.5 tons. And by 2005, capacity should hit 12 tons. Some of these $800 million Ariane 5 Evolution improvements will include upper-stage motor upgrades.

"We are two to three years ahead of our competitors -- in particular the Americans, like Boeing and Lockheed Martin. We have to consolidate this lead as soon as possible," said Roger-Gerard Schwartzenberg, the new French minister of Research, in a recent interview in the daily paper Figaro.

Like the American space shuttle, the Ariane 5 heavy-lift launcher is composed of a main cryogenic stage, with two solid-fuel, strap-on boosters that provide 92 percent of the total thrust during the first two minutes of flight. The solid rocket, 27 meters (89 feet) high and 3 meters (10 feet) in diameter, and weighing in at 589,600 pounds (267,440 kilograms), is 10 times larger than any previously built in Europe.

Ariane 5's great advantage is having "dual-launch" capability -- the ability to lift two medium-to-large-size satellites into orbit with a single launch -- while cutting in half the launch cost-per-unit factor. But today, as Ariane 5 enters the market, communication satellites are becoming larger and heavier than ever. The next generation of satellites weighs 3.5 to 4 tons (3,550 to 4,065 kilograms) each, too large for two of them to fit within Ariane 5's payload limit of 5.9 tons (5,995 kilograms) for geostationary orbit, the most popular position for communication satellites.

By 2005, most of the geostationary communication satellites will weigh even more. At the same time, dual-launch capability is the crucial strategy of the future, and the European launcher will have to double Ariane 5's performance by 2005.

This initial test analyzed a new part of the composite propellant, which uses a European-produced binder. The test also looked at the wear and tear accrued over six years on a vital nozzle, as well as behavior in the booster's systems and parts. Yet another part of the test involved simplifying the boosters' electric ducts along with stretched-nozzle testing, heralding a forthcoming development.

Changes resulting from the test will mean gaining weeks to months in the processing cycle of the booster's production. The solid-fuel rocket motor built by Europropulsion comprises a nozzle, an igniter and three segments. After the first two successful commercial launches of Ariane 5, five to six launches a year of this new heavy-lift launcher are planned to coincide with the phasing out of the Ariane 4, the highly successful workhorse of Europe's privately-operated Arianespace for the past 12 years.

Europropulsion has also kicked off further complementary development initiatives to enhance Ariane 5's performance. The main modifications include welding the three cylindrical sections of the booster to decrease weight, as well as loading additional propellant in the forward segment to increase performance.