An Ariane-5 heavy lifter powered into the skies from the European Space Agency (ESA) launchpad here, taking with it a 689-million-dollar orbital observatory that scientists hope will yield insight into the origins of the universe.

After a 29-minute flight that took it to a height of 2,350 kilometers (1,468 miles), the rocket released the 3.8-tonne X-Ray Multimirror Mission (XMM) telescope.

ESA operations managers at Darmstadt, Germany, later reported that the XMM was under control and its solar panels were feeding it electrical power.

"This was a collective and profoundly European achievement," said Jean-Marie Luton, president of ESA's marketing arm, Arianespace. "The launch of this new rocket puts us ahead of all our rivals."

Delicate yet powerful, the XMM comprises three long tubes of 58 sets of golden, precision-honed concentric mirrors that will in effect will vacuum up traces of X-ray emissions from the far reaches of the universe.

X-ray sources can come from some of the most violent and intriguing phenomena in the universe, such as black holes, collapsed stars whose gravitational pull is so strong that light is gobbled up, and "vampire stars" which suck up matter out of their neighbours.

Astrophysicists say the XMM -- the result of 10 years' work -- should be at least five times more sensitive than the Chandra, the US X-ray telescope taken aloft by the space shuttle in July, which has already provided stunning data.

XMM's initial orbit took it far into space to an apogee of 114,000 kms (71,250 miles) from the Earth and a perigee, or closest point, of 850 kms (525 miles).

Over the next week or so, the craft's thrusters will be repeatedly be fired to correct the perigee to 7,000 kms (4,350 miles), although the apogee will remain the same.

The reason for this highly elliptical orbit is to keep the telescope away from the radiation belts around the Earth as long as possible, in order to pick up weak X-ray sources, said XMM project chief Robert Laine.

Fine-tuning and double-checking the instruments means that it will take several months before the XMM is fully available for astronomical work, although data should start to come in from around January 4.

The Ariane-5 is a 754-tonne giant designed to place payloads of 6.8 tonnes into geostationary orbit. Modified versions should bring this to 12 tonnes by 2005.

The rocket suffered a catastrophic setback on its first flight, on June 4 1996, when it blew up just 37 seconds after liftoff, atomising its payload of four science satellites.

A software error was found to be the cause, and the rocket has since undergone two successful "qualification" missions. Friday's was its first fee-paying flight, carrying a price of 145 million dollars.

In total, 34 Ariane-5s have been ordered, and Arianespace hopes to launch up to 10 of them per year. The next will take place "late February, early March," said Luton.

The backbone of ESA's operations at the moment is the Ariane-4, which has been in operation since 1988. On December 3, it launched successfully for the 50th time in a row.

ESA has a 50-percent share in the increasingly crowded market for commercial satellite launches.

The United States, Russia and China are the other major national players, and an innovative venture, Sea Launch, which uses a converted North Sea oil platform as a launch pad, joined the game earlier this year.