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The Ariane 5 awaits liftoff on its ill-fated launch. Photo: ESA/CNES/Arianespace/CSG

Arianespace was hit by a massive setback Wednesday night when the upgraded Ariane 5 rocket failed minutes into its debut flight, plummeting into the Atlantic Ocean with two communications satellites aboard.

It was supposed to be a mission to build the reputation for the new launcher that the European consortium is staking its future upon. Sporting more powerful first and second stage engines, the rocket is designed to loft 10,000 kg into geosynchronous transfer orbit, allowing for easier pairing of dual-payload missions that Arianespace needs to make the Ariane 5 succeed. The venerable Ariane 4 will be retired from service early next year after two more flights.

What's more, American rivals Lockheed Martin and Boeing successfully launched their next-generations rockets on maiden flights from Cape Canaveral this year. The Atlas 5 and Delta 4 join the Ariane 5, Russian Proton and Sea Launch programs in a cut-throat commercial marketplace that has more rockets than payloads to carry.

But the Ariane 5 ECA malfunctioned on its inaugural space flight, dealing the Ariane 5 program its third complete mission failure in 14 launches. One additional mission -- a test flight -- reached a low orbit and most observers also consider that a failure.

After a last-second abort two weeks ago because of ground system troubles, Wednesday's launch occurred as scheduled around 2221:25 GMT (5:21:25 p.m. EST) as the Ariane 5 thundered from the Guiana Space Center on the northeast coast of South America.

Tracking cameras at the jungle launch base followed the Ariane 5 as it headed eastward into the night sky. Just over two minutes into the flight, the twin solid rocket motors burned out and separated from the cryogenic core stage.

That core stage was to burn for nearly nine minutes, guzzling liquid hydrogen and liquid oxygen by the new Vulcain 2 main engine. But something went wrong about three minutes after liftoff, Arianespace CEO Jean-Yves Le Gall said.

"Right now it is too soon to give a clear explanation of the failure," Le Gall said through an English translator.

"As you know our job is difficult as we have been reminded tonight in a most cruel way. Tonight's failure is very serious but we have been through difficult times before, always overcome our difficulties and we will overcome this one once again. Our teams are already working."

Live tracking data of the ascent, shown in the Arianespace broadcast of the launch that was beamed via satellite to Europe, indicated the rocket was no longer gaining altitude and speed by four minutes into the flight. The public affairs commentators made first mention of a problem around six minutes after liftoff.

A Vulcain 2 cryogenic main engine. Photo: Snecma/studio Pons

The Vulcain 2 powerplant is a modified version of the engine used on previous Ariane 5 launches. It has been changed to increase thrust by 20 percent, increasing the amount of cargo that can be carried aloft.

Made by Snecma, the Vulcain 2 burns a mixture with 20 percent more liquid oxygen under slightly higher pressure than the previous version, according the European Space Agency.

"As a result of this change in the mixture of propellants, FiatAvio (Italy) has had to develop a new oxygen turbopump, capable of 13,000 rpm and delivering pressure of 161 bar. It has also been necessary to increase the capacity of the liquid oxygen tank in this stage by 15 tonnes. This has been achieved, without altering the structure of the stage, by lowering the bulkhead between the liquid oxygen and hydrogen tanks by 640mm," a recent ESA press release said.

"Another improvement in Vulcain 2 is a new nozzle divergent, manufactured by Volvo Aero (Sweden), which enables the emissions from the turbopumps to be reinjected into the main system and improves the engine's performance at high altitudes."

The other key difference on the new Ariane 5 is the cryogenic upper stage, a more powerful replacement to the storable propellant stage used on the previous Ariane 5G rockets. However, Wednesday's launch ended several minutes before the new stage could be used. The stage is derived from the Ariane 4 program and uses the same engine.

Destroyed in the failure was Eutelsat's Hot Bird 7 direct broadcasting satellite and the French Space Agency's Stentor communications satellite technology demonstrator. Eutelsat also flew satellites on the Atlas 5 and Delta 4 inaugural flights this year, successfully placing the Hot Bird 6 and W5 spacecraft in orbit, respectively.

The Hot Bird 7 satellite prepared for launch in Kourou. Photo: ESA/CNES/Arianespace/CSG

Hot Bird 7 was to have joined other Hot Bird satellites in geostationary orbit at 13 degrees East along the equator -- above the African nation of Gabon. The new craft would have replaced the Hot Bird 3 satellite in Paris-based Eutelsat's fleet that beams direct-to-home programming to almost 100 million customers across Europe, northern Africa and the Middle East.

Built by Europe's Astrium, Hot Bird 7 would have operated with up to 40 transponders in the Ku-band, a so-called superwidebeam and two steerable beams to fill the increasing demand for new services, including Internet and multimedia programming in addition to television and radio.

Enclosed within a barrel-like dual-payload adapter rode the Stentor technology demonstrator for the French space agency CNES.

Stentor was built to demonstrate the feasibility and usefulness of a large number of communications technologies and satellite components during its 9-year mission. Taking part in the Stentor project along with CNES were France Telecom and the French Ministry of Defence.

The Hot Bird 7 satellite prepared for launch in Kourou. Photo: ESA/CNES/Arianespace/CSG

About 80 percent of the satellite's experimental parts were new to the satellite communications industry. Both equipment and new telecommunications methods were to be demonstrated and evaluated with Stentor, the know-how to be applied to the communications spacecraft of the future.

Stentor was jointly built by Astrium and Alcatel Space. Its final slot in geostationary orbit would have been 11 degrees West longitude.

Arianespace has scheduled a news conference for 1300 GMT (8 a.m. EST) Thursday to provide information on the mishap.

It is not yet known what the impact will be on the next Ariane 5 launch, scheduled for the evening of January 12, carrying the European Space Agency's Rosetta comet probe. That craft must leave Earth within a tight 20-day period to achieve the proper trajectory.