European government ministers, showing a restiveness they have never before exhibited, have refused to endorse the full budget proposed for the international space station until the project’s shuttle-related paralysis is resolved.

Meeting Dec. 5-6 here to set mid term space priorities and budgets, European Space Agency (ESA) government officials voiced concerns that a business-as-usual approach to their space station investment would be throwing good money after bad.

These governments nonetheless stopped short of sending a thumbs-down message to NASA, the station’s lead agency . They accepted arguments presented by ESA managers and by the German government that an overly negative signal sent to Washington would undermine Europe’s efforts to get its billion-dollar astronaut laboratory launched to the space station as soon as possible.

Like the Japanese Experiment Module, the European Columbus facility was designed to be launched only by the U.S. space shuttle. With just 60 months to go before the shuttle fleet is scheduled to be retired, Europe is battling to assure that its laboratory, which is in storage in Germany, finds a secure place on the shuttle’s questionable manifest.

ESA Director-General Jean-Jacques Dordain said the ministers’ decision to continue funding at least some station-related activities provides enough support to bolster Europe’s case.

“With this decision I shall be able to send a signal to the United States that yes, we need to get our benefits from our past investment with an early launch of Columbus,” Dordain said at the close of the conference.

Officials said that without the strong backing of the German government — Europe’s biggest space station investor — the minimal investment that was approved here would not have been secured.

“We are so far advanced in this program and we have hundreds of people waiting to operate their experiments,” said Sigmar Wittig, chairman of the executive committee of the German Aerospace Center, DLR. “There is also the industrial aspect — you don’t just turn people off and on. You need a certain continuity in the program.”

Wittig said in a Dec. 6 interview that the political angle also was an important factor in deciding how to proceed with Europe’s space station investment.

“Let’s face it: We should not relay a negative message to the United States,” Wittig said. “If in two years we determine that the shuttle is nearing retirement and we have to have a Plan B, we can focus on it at that point. This was not the time to focus on it.”

Germany had an uphill fight in winning over its ESA partners. Even Italy — a strong NASA partner in the space station — was reluctant to endorse the program. Sergio Vetrella, president of the Italian Space Agency, said Italy agreed to invest only the minimum needed to maintain Europe’s expertise while awaiting a Columbus launch.

ESA had asked for a total of 650 million euros ($762 million) between 2005 and 2008 to cover the costs of maintaining the Columbus laboratory, preparing for its launch and operating the facility. Columbus’ launch date will depend on the shuttle’s return to flight; the facility currently is manifested for launch in late 2007 or early 2008.

ESA had asked for an additional 320 million euros to fund life sciences research to prepare for the full-time use of the station.

Of the total 970 million euro request, however, the ESA ministers approved just 635 million euros. And part of the approved funding has conditions attached to it, meaning the total that ESA ultimately will receive is unclear.

Daniel Sacotte, ESA’s director for human spaceflight, said the agency has agreed to parcel out its station spending in small steps, with each succeeding payment dependent on what happens with the shuttle and with Europe’s Automated Transfer Vehicle (ATV), a large unmanned space tug to deliver supplies to the station.

Originally nine ATVs were to be built. Then the total was reduced to seven. Sacotte said Dec. 6 that ESA has now decided to launch one ATV and to await its performance — and the shuttle’s return to flight — before ordering one more. A third ATV will not be ordered until the vehicle’s full range of capabilities — rendezvous and docking, and reboosting the station’s orbit — have been proven.

“If there is no launch of our Columbus laboratory, then the scenario is completely different,” Sacotte said. “What was agreed by the ministers is enough for me to continue to make our case at NASA. The message is: We are confident, but we are not giving anyone a blank check.”

Sacotte said that even if the Columbus facility is not launched, Europe wants to find a way to use the station, which is why microgravity research will continue.

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