Super rocket held on pad

The Ariane 5 is operating in a depressed market

The most powerful rocket ever constructed in Europe failed to get off the launch pad on Thursday.

The new Ariane 5-ECA was just 13 seconds away from its inaugural flight when controllers stopped the countdown sequence.

The new version of the rocket had to be rolled back to its assembly shed

Technical problems were encountered with the launcher's main Vulcain 2 engine.

The Ariane 5's mission is to push two satellites towards geostationary orbits. A new date and time will now have to be set for the launch at Kourou in French Guiana.

"When the cryogenic arms began to open providing hydrogen and oxygen to the launcher, failure occurred and the countdown was stopped," Jean-Yves Le Gall, the CEO of Arianespace, the rocket's operator, said.

"That is all we can say for the moment. I propose to say no more this evening and information will be given tomorrow (Friday)," he said.

Technicians began emptying the cryogenic fuel from the rocket's main and upper stages late on Thursday before transferring the launcher back to its assembly shed for further checks.

Fewer customers

The vehicle, the latest variant in the highly successful Ariane series, is capable of carrying 10 tonnes of payload into space.

This puts the rocket at the top end of the very competitive, but currently depressed, launcher market.

The Ariane 5-ECA will go head-to-head for business with Lockheed Martin's Atlas 5 and Boeing's Delta 4, both of which have debuted within the last few months.

But whereas the two US rockets will benefit from a steady stream of orders from the American military, the Ariane will be dependent largely on commercial customers.

During the 1990s, these clients were demanding vehicles capable of launching ever heavier geostationary telecommunications satellites - from 2.5 to five tonnes.

Then, towards the end of the decade, the market turned down and although the size of satellites has continued to increase, there are fewer of them to place in orbit.

Better performance

Nonetheless, Arianespace, which operates Europe's rockets for its member states, hopes the bigger launcher will find success.

Because the 10-tonne can deliver into orbit two different satellites at once, it can keep costs down.

Thursday was supposed to be just such a dual launch. The Ariane 5 is loaded with a Hotbird TM7 satellite, for the European telecoms consortium Eutelsat, and Stentor, an experimental communications satellite for the French space research institute CNES.

Boeing's Delta 4 can rely on military orders

The new rocket is a development of the generic Ariane 5 launcher that went into full commercial service in 1999.

It has two solid boosters to lift it off the launch pad, a cryogenic main stage to do most of the work of getting into orbit, and an upper stage to place the satellites in the target orbit, in most cases a geostationary transfer orbit of up to 36,000 kilometres from where their onboard propulsion systems take them into their final orbits.

To get the new, beefed up performance, the solid boosters carry more propellant and the main Vulcain cryogenic engine has been modified to improve its combustion of liquid oxygen and hydrogen.

The main difference, however, is the introduction of a new upper stage (ESC-A) based on tried and tested technologies used on the much older Ariane 4 launcher.