The European Space Agency has carried out the maiden launch of a massive robot freighter designed to rendezvous automatically with the orbital space station.

The Automated Transfer Vehicle (ATV), a nearly 20-tonne payload the size of a London double-decker bus, blasted into the skies aboard a beefed-up Ariane 5 launcher.

After being placed in orbit, the cylinder-shaped craft will deploy its solar panels and gently find its way to the International Space Station (ISS) and berth with it.

The launch had initially been scheduled for Saturday but was postponed for further checks.

The ATV will deliver seven and a half tonnes of food, water, pressurised air, fuel and personal items to the ISS crew.

After docking, the ATV will use its engines to propel the station, which is being gently tugged earthwards by terrestrial gravity and lingering atmospheric molecules, to a safer height in low orbit.

After six months or so, the craft will detach from the ISS, taking with it rubbish accumulated during the station's mission. The trash and freighter will then safely disintegrate over the Pacific, mission scientists say.

Weighing 11 tonnes unloaded, measuring 10.3 metres long and 4.5 metres wide and laden with hi-tech optical navigation, docking sensors and communications equipment, the ATV has cost ESA 1.3 billion euros ($2.16 billion).

The payload, handled by an Ariane 5 ES, is the biggest undertaken by ESA yet.

It will be placed in orbit at an altitude of 260 kilometres, and then take about two weeks to edge up to the ISS, in order to test its systems and wait patiently for the departure of a US space shuttle, the Endeavour, before docking with the station.

Deployment of the ATV has been put off for some four years because of delays in assembling the ISS after the loss of the shuttle Columbia in February 2003.

The first ATV is named after Jules Verne, the French author who pioneered science fiction. Four more cargo ships are in the works, with their assembly and launch each costing just over 300 million euros.

Europe's other major contribution to the ISS has been a 1.4-billion-euro science module which was attached to the burgeoning orbital outpost last month.

The ISS, whose assembly began in 1998, now has a mass of more than 240 tonnes and is so big that it can be seen at night with the naked eye, perceptible as a small, moving star.

-AFP