Europe's Ariane 6 blasts off on maiden flight

Standing 56 metres tall, Europe's newest uncrewed rocket left the launch pad in French Guiana about 4pm local time at the start of a nearly three-hour flight designed to end a year-long hiatus in European launches.

"Propulsion and trajectory are nominal," the mission's launch director said in live pictures beamed to the headquarters of the European Space Agency in Paris, where employees cheered and applauded the lift-off.

The launch went ahead after checks showed a "small issue" in a data acquisition system, pushing the beginning of a launch window back by one hour.

The inaugural mission is not a commercial flight but if all goes well, it is scheduled to deploy a handful of satellites and experiments from European agencies, companies and universities.

Ariane 6 was developed at an estimated cost of 4 billion euros ($A6.4 billion) by ArianeGroup, co-owned by Airbus and Safran.

But its arrival, originally due in 2020, has been repeatedly delayed.

Since the agency retired its workhorse Ariane 5 rocket more than a year ago, Europe has had no independent means of sending its satellites into space, while war in Ukraine has cut the continent's ties to Russian Soyuz rockets and Italy's Vega C is grounded.

A new generation of small European commercial launchers remains in early development mode.

"Ariane 6 is fundamental for Europe's space ambition," Toni Tolker-Nielsen, ESA's acting director of space transportation, told Reuters from the control room at Europe's space port.

"It is about sovereign access to space for institutional and governmental missions ... and this need has been even more emphasised in view of the geopolitical situation."

Europe's temporary isolation in an increasingly global space-launch market was exposed last year when European agencies were forced to switch some payloads to the Falcon 9 rockets of SpaceX in the United States.

Ariane 6 owes its existence to a decision by ESA's 22 member countries in 2014 to develop a family of rockets in the face of fierce competition from Elon Musk's private space venture.

The United States and dozens of other countries have come to rely heavily on Falcon 9 for reaching orbit as everyday life on earth becomes increasingly reliant on satellite links and data.

ESA countries have launched an initiative to boost a growing number of small-launcher projects that could pave the way for a future private competitor to SpaceX and Ariane 6 itself.

"Ariane 6 is not quite there yet in terms of competitiveness but they want to get there," said Ian Annett, former deputy CEO of the UK Space Agency.

If all goes well with its debut, Ariane 6 has about 30 customer missions to launch over the next several years.

That includes 18 launches for Amazon's Kuiper internet constellation of thousands of satellites, one of a few planned rivals to SpaceX's Starlink.

Australian Associated Press