Europe's ATV space truck has blasted off from the Kourou base in French Guiana.

The robotic truck is heading to the International Space Station (ISS) with new supplies of food, water, air, and fuel.

It is also carrying experiments and spares for the high-flying astronaut outpost.

The ship's Ariane 5 carrier rocket left the ground at 04:34 GMT, with the flight to orbit taking 63 minutes.

At 20 tonnes, the ATV is the biggest ship servicing the station now that the US shuttles have been retired.

The Ariane placed the Automated Transfer Vehicle (ATV) at an altitude of about 260km. The freighter will use its own thrusters to climb a further 130km to the ISS over the course of the next few days.

"This is the start of a long journey; there will be other critical phases, especially the rendezvous [with the ISS] that will take place during the night of the 28th and 29th, Paris time," said European Space Agency (Esa) Director General Jean-Jacques Dordain.

Fair share

Ground controllers received confirmation half-an-hour after the truck had separated from Ariane's upper-stage that its solar panels had been deployed, and that the onboard power systems were working.

This ATV is the third such craft to be sent to the station by Esa, and has been dubbed Edoardo Amaldi in honour of the 20th Century Italian physicist (a co-discoverer of slow neutrons, which made possible nuclear power).

Two previous vehicles have been flown, in 2008 and 2011.

The trucks are part of the barter arrangement that Esa has with its international partners on the ISS project.

Instead of handing over cash to cover station running costs, Europe has taken on the major responsibility of platform logistics.

In return, it gets residency rights for its astronauts - one individual to spend six months in orbit, every couple of years.

The current flier, Dutchman Andre Kuipers, will be on hand at the ISS to help unload the truck when it arrives.

Max cargo capacity : 7.6 tonnes of dry and liquid supplies

: 7.6 tonnes of dry and liquid supplies Mass at launch : About 20 tonnes depending on cargo manifest

: About 20 tonnes depending on cargo manifest Dimensions : 10.3m long and 4.5m wide - the size of a large bus

: 10.3m long and 4.5m wide - the size of a large bus Solar panels : Once unfolded, the solar wings span 22.3m

: Once unfolded, the solar wings span 22.3m Engine power : 4x 490-Newton thrusters; and 28x 220N thrusters

: 4x 490-Newton thrusters; and 28x 220N thrusters Capability : The ship finds and docks with the ISS autonomously

: The ship finds and docks with the ISS autonomously No re-use: The vehicle is destroyed with ISS rubbish at mission end

The total cargo mass of ATV-Edoardo Amaldi - if you add in the fuel the ship uses for its in-orbit manoeuvres - is just over 6.5 tonnes.

This includes the largest ever load of dry cargo - everything from clothing and new toothbrushes to the Lego kits that astronauts use in the education demonstrations they beam to Earth.

Items with more significance than children's toys would be components for new scientific experiments and an American unit to recycle urine into drinking water.

ATV-Edoardo Amaldi will stay attached to the ISS until September. One of its key tasks over that period will be to push the station higher into the sky, to counteract the tendency of the platform to drift back to Earth as it drags through the residual atmosphere still present at its altitude.

"The ISS has a natural decay per day of 50-100m right now," explained Nico Dettmann, who runs Esa's ATV programme. "We plan nine re-boosts of the station in the course of the mission."

Image caption The ATV pays part of Esa's subscription to belong to the ISS club

Europe will send two further freighters to the station, in 2013 and 2014.

These ships will fulfil Esa's commitments to the ISS partners through to about 2016.

Europe must then work out how to meet its "subscription" up to 2020, the current planned limit for operations on the orbiting platform.

One solution that has been suggested is that the ATV's service module (the part of the craft that drives it through space) be evolved into a tug that can carry the sophisticated manned capsule known as Orion, which the Americans are now developing to go beyond the space station, to destinations such as asteroids and Mars.

"There are different opportunities under consideration," said Michael Menking from Astrium, the pan-European space company that leads the production of ATVs from Bremen, Germany.

"ATV has a programmatic duty to pay the ISS operation obligation to the Americans. Therefore, it is very important that whatever we do as an evolution of ATV, it can be bartered with the Americans. And that means they have to agree to it," he told BBC News.

There is also an Esa study codenamed VAC, for Versatile Autonomous Concept, which is looking at the idea of a big spacecraft derived from the ATV that could do a variety of jobs in Low-Earth Orbit, such as docking with redundant satellites and pulling them out of the sky.

Esa is in the midst of some intense activity.

The past six months have seen it introduce two new rocket systems at its Kourou spaceport - a European version of the long-established Russian Soyuz rocket, which the agency plans to use to launch navigation satellites and scientific payloads; and the Vega rocket, which is an all new vehicle for lofting satellites that are really too small to go on either Soyuz or Ariane.

"The launch of Soyuz in October, the launch Vega in February, and the launch today of Ariane with ATV-Edoardo Amaldi - yes, it's been a fantastic six months. We are a significant space power. I can say that," said Mr Dordain.

Jonathan.Amos-INTERNET@bbc.co.uk and follow me onTwitter