BERLIN — Europe’s work on the service module for NASA’s Orion crew-transport vehicle has made up most, but not all, of the slip in schedule and is on track for delivery to NASA in time for a late-2017 launch, European government and industry officials said.

While the delivery deadline remains challenging, the earlier problem of the module’s excess weight has been resolved and the prime contractor is not having to resort to double- and triple-shifts to get the job done, officials said.

“The preliminary design review for the service module has been successfully concluded and that is a key milestone in the consolidation of the schedule,” European Space Agency Director-General Jean-Jacques Dordain said here May 20 during the Berlin Air Show.

NASA Administrator Charles Bolden said here that the United States remains committed to a long-term partnership with Europe on Orion that would extend well beyond the current agreement, calling for one complete service module and spare parts for a second.

“Europe and the United States have established a partnership with Orion and the service module that is unprecedented,” Bolden said. “The United States has never — ever, ever — partnered with another nation and said, ‘You’re on the critical path and I can’t do this without you.’

“And that’s exactly what we said, and we did it with intention because we wanted to send a message. People can pretend that they don’t hear the message, but we’re in this for the long run as partners.”

The Orion service module, to be fitted on the back end of the crew transport capsule to provide propulsion and crew supplies, is currently part of a longstanding barter agreement between ESA and NASA under which ESA provides services, rather than cash, to NASA in return for ESA’s 8 percent use of the international space station’s common resources.

ESA has been fulfilling its barter obligations up to now by providing Automated Transport Vehicle (ATV) launches sending fuel, water and other cargo to the station. The fifth and final ATV launch is scheduled for July.

In November 2012, ESA governments approved extending their participation in the space station to 2020. The fifth ATV launch covers ESA’s barter obligations to NASA to 2017. To cover the period to 2020, ESA agreed to spend 455 million euros ($623 million) on the Orion service module — enough to cover a full flight-ready module and parts for a second flight.

But because of a debate among ESA nations, mainly Germany, France and Italy, over who will pay for ESA’s other station operating costs through 2020, the governments authorized ESA to spend only 250 million euros on the Orion work.

The remaining 205 million euros was left for the next conference of ESA government ministers, scheduled for December in Luxembourg.

Dordain said he remained confident that his governments will finance the remaining service module requirements to complete the contract with Airbus Defence and Space’s Bremen, Germany, division, which is the service module’s prime contractor.

Johann-Dietrich Woerner, chairman of the German Aerospace Center, DLR — Germany’s space agency — said Germany backs full approval of the extension to 2020 and also wants ESA governments to support NASA’s proposed extension of station operations to 2024.

“Germany is supporting this because our strategy is very simple,” Woerner said here May 20. “We would like to use [the station] as long as it is accessible.”

France has been less interested in the station than Germany and in the past has conditioned its support on Germany’s continued financial backing of Europe’s Ariane rocket program. That condition remains, but May 20 remarks here by France’s space minister, Genevieve Fioraso, suggest that France is not contesting the extension to 2020.

In a briefing with journalists, Fioraso said France nonetheless has issues with extending its participation to 2024 without an indication from NASA that its support for rocket builder Space Exploration Technologies Corp. will not permit SpaceX to proceed with “dumping, because that’s what it is,” of cheap SpaceX rockets on the international market where they compete with Europe’s Ariane 5 vehicle.

Given ESA’s and France’s support for the Ariane rocket line, it remained unclear whether NASA’s station resupply services contract with Hawthorne, California-based SpaceX — and a similar one with Orbital Sciences of Dulles, Virginia — is qualitatively different from what occurs in Europe.

One ESA official said the agency has received no formal word from France that the NASA-SpaceX relationship will be a hurdle to Europe’s continued space station role.

Completion of the preliminary design review of the Orion service module was announced May 19 — nearly a year after the original schedule, but on time following ESA’s revised schedule set last November.

Bart Reijnen, Airbus’ head of orbital systems and space exploration, said completion of the review gives the program a much-improved status from where it was a year ago, when it was many months behind schedule.

In a May 20 interview, Reijnen said the service module’s weight issue has been resolved but that the overall schedule remains challenging. The critical design review, he said, is scheduled for late 2015 — just two years before the planned launch assuming no delays on the U.S. sides.

“I would not say that mass today is an issue,” Reijnen said. “We have sufficient [schedule] margin at the moment, but of course we would prefer that this margin increase and not vaporize in the next 18 months. There was a mass issue, and there is still a mass challenge to increase our margins.”

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Peter B. de Selding was the Paris Bureau Chief for SpaceNews.