By Jo Twist
BBC News science and technology reporter
Europe's "super-rocket", the Ariane 5-ECA, will be back in action in January 2005, says its operator Arianespace.
The ECA can lift more for less
The launch will be the vehicle's first since its maiden flight ended in an explosive failure in December 2002.
The qualification flight was originally scheduled for November, but was then put back after a review highlighted a number of outstanding technical issues.
The ECA is important to the European launch industry because it can lift multiple payloads at reduced cost.
At the moment, "generic" versions of the Ariane 5 vehicle are fulfilling satellite launch duties at the European spaceport at Kourou in French Guiana.
"The main issue for us is now to complete a full 'wet' dress rehearsal," Jean-Yves Le Gall, Arianespace's chief executive, told the BBC News website.
"During this operation, we will prepare and activate the launch vehicle up to just before engine ignition."
He added: "The wet rehearsal is scheduled for early January. We are fully confident that the launch will take place a few weeks after, at the end of January or early February."
The delay of Flight 164 will allow for the launch of a standard Ariane 5 rocket on 10 December.
It will carry observation and reconnaissance satellites for the French defence ministry.
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Mr Le Gall denied speculation that pressure had been exerted on Arianespace to launch the military satellites ahead of the "test loads" on the ECA.
"There was no pressure on Arianespace from the French authorities to place the launch of Helios 2A ahead of the Ariane 5-ECA," said Mr Le Gall.
"The decision to launch Helios 2A by an Ariane Generic before the Ariane 5-ECA was based exclusively on the technical status of the two launch vehicles."
On board the ECA's Flight 164 in January - the first of two qualifying flights before commercial launches can begin - will be less valuable payloads; a Spanish satellite and an experimental tank of water.
SloshSat will help scientists study how fluid behaves in microgravity
The SloshSat-FLEVO small satellite carrying 33.5 litres of water is designed to help European scientists find out more about the movement of fluid in microgravity and its effects on satellites.
The investigation that followed the 2002 failure found that a leakage in the cooling system affected the thrust on the ECA's main Vulcain-2 engine. Excess heat deformed the nozzle and the vehicle veered off its planned trajectory.
An automatic self-destruct system destroyed the launcher 456 seconds into the flight, dumping two satellites worth 600 million euros into the Atlantic Ocean.
Mr Le Gall said that all the tests on the Vulcain 2 engine had been successfully completed and that the motor was now fully qualified for flight.
He added that all component testing had been completed and that the team was now in the process of formally clearing all the technical documentation.
For the time being, generic rockets will continue to perform the bulk of Arianespace launches - in May, the company signed a contract with EADS-Space Transportation for the construction of 30 new vehicles.
These rockets are capable of carrying up to six tonnes into space. The last launch in July - the generic 5's 19th flight - carried the Canadian-owned Anik F2 telecoms satellite.
The newer Ariane 5-ECA, however, has much more power and can lift up to 10 tonnes of payload towards geostationary (GEO) or low-Earth orbit (LEO).
This is very important for Arianespace as a commercial launch company because it means if more than one satellite can go up at the same time, it can sell its services at a lower price.
Arianespace is the company charged under a convention with the European Space Agency to operate and market Europe's rocket services.
It currently has more than 50% of the international market for satellites launched to GEO.