SAN SEBASTIAN, Spain — Confronting a budget crisis that likely will take years to resolve, European governments have begun debating how to manage the increased operating costs associated with three separate launch vehicles and launch installations at Europe’s spaceport in French Guiana.

A parallel debate is taking place over whether Europe’s governments can afford to invest in a major improvement to the current Ariane 5 heavy-lift rocket even as they start designing a vehicle to succeed it.

In an illustration of how the discussion is being played out, the head of the German Aerospace Center, DLR, said here that he is “totally against the idea of an Ariane 6 vehicle.” But Johann-Dietrich Woerner said Germany could, at least in principle, support co-investment in an improved Ariane 5 even as work starts on a successor rocket.

The French government, which is expected to finance the biggest share of the post-Ariane 5 rocket even as it pays for nearly 50 percent of the current Ariane 5, has indicated it would use a public bond issue as part of a broader economic-stimulus package to finance work on the next-generation vehicle.

European governments in 2008 agreed to continue preliminary work on an Ariane 5 Midlife Extension vehicle that would employ a cryogenic upper stage and would increase Ariane 5’s performance in its core business: simultaneously launching two telecommunications satellites into geostationary transfer orbit.

The current Ariane 5 ECA rocket is able to loft two telecommunications satellites with a combined weight of nearly 9,000 kilograms. A series of small upgrades, including reducing its weight, should, by 2015, nudge that capacity to close to 10,000 kilograms, according to the French space agency, CNES.

European Space Agency (ESA) governments in late 2008 agreed to fund initial work on the Midlife Extension vehicle, with the funds needed to complete development and testing — 1 billion euros ($1.24 billion) or more — to be decided in 2012 at a meeting of ESA government ministers.

Equipped with a new, cryogenic upper stage, the Ariane 5 Midlife Extension vehicle would be able to carry two satellites weighing a combined 11,500 kilograms into geostationary transfer orbit starting around 2017.

But these governments will also be asked in 2012 to approve the start of work on an Ariane 5 successor, to debut around 2025, and possible upgrades to the small Vega rocket, whose inaugural flight has been delayed to early 2011.

Still unclear at this point is whether ESA members will be asked to pay substantially more for the operation of the Guiana Space Center in French Guiana once the spaceport is fully operational with three vehicles at three launch pads. A European version of Russia’s Soyuz rocket is scheduled to begin operations at the Guiana center late this year.

The Arianespace commercial launch consortium of Evry, France, which will be operating Soyuz and Vega in addition to Ariane 5, has begun assessing maintenance and operating costs and is advising ESA and CNES rocket-design teams to take account of life-cycle operating costs as well as the costs of a rocket’s construction.

Addressing the Space Propulsion 2010 conference here May 3, Arianespace Program Director Louis Laurent gave the example of helium, used to pressurize fuel tanks and flush fuel lines. Once an engine has been designed for helium, it is difficult to switch to some other gas. But helium, he said, is expensive to use.

Laurent said designers should take account of how much different types of fuel — solid, cryogenic or storable propellants — and other consumables cost to produce and to use over the life cycle of a rocket that may remain in operation for 20 years or more.

Similarly, Laurent said Ariane 5’s current economic model, based on launching two satellites at a time, was originally designed to reduce costs to satellite owners. It is not, he said, a requirement of the market.

“Operating-cost constraints need to be included from the early design phase,” Laurent said. “Beyond the classic constraints of reliability and launcher cost, robustness — meaning the ease of production and operations — will be drivers for future success.”

Patrice Plotard, head of future launchers at Astrium Space Transportation, the prime contractor for the Ariane 5 rocket, said whatever vehicle follows Ariane 5, it needs “a big reduction in operating costs. In our discussions with our engineers, this is one of the main drivers” for the future vehicle

“We need to design for producibility, and not just design for performance, which was the main goal in the past,” Plotard said. “We need to consider it as an industrial product. This requires a change in mindset even within Astrium Space Transportation. It cannot be just an excellent product from a production viewpoint.”

Michel Eymard, director of launchers at CNES, said the post-Ariane 5 vehicle needs to be designed to provide a 40 percent reduction in the cost of putting a kilogram of payload into orbit compared with today’s Ariane 5 ECA rocket. It also needs to be easy enough to operate so that it can change its mission within two weeks of a launch.

Early CNES designs of the post-Ariane 5 rocket suggest a modular vehicle that typically would launch one large telecommunications satellite at a time, not two, and would be able to survive mainly on the limited market for European government payloads. Today’s Ariane 5 is mainly a commercial launcher that would require substantially more government investment to be able to survive primarily on government business.

Peter B. de Selding was the Paris bureau chief for SpaceNews.