PARIS—The European-built service module for NASA’s Orion crew-transport vehicle will be three months late in being shipped to the United States following modifications to the design recommended by a June 16 program review, a senior European Space Agency official said June 17.

The new shipment date has been tentatively set for late April, rather than late January. ESA, NASA and the two main industrial teams – Airbus Defence and Space for the service module and Lockheed Martin Space Systems, which is prime contractor for Orion — met June 16 at ESA’s Estec facility in Noordwijk, Netherlands, to conclude a service module critical design review.

Nico Dettman, head of ESA’s space transportation department, said the delay is partly a result of the fact that several components could not yet be assessed in the full critical design review and need more time to be integrated into the design.

Dettman said another issue forcing the delay resulted from a reassessment by NASA of the stresses the service module needs to be capable of handling in orbit. These “in-orbit load” specifications have recently been tightened. But any design modifications will not affect the service module’s core structure, he said.

“If it has an impact, it will be limited to the solar array wings, not the structure – nothing where flight hardware has been manufactured that we will have to touch,” Dettman said. “It’s a late modification, but not too late.”

“They are not nice, but it is quite normal and they happen all the time,” Dettman said of the fresh set of requirements, often referred to as customer change notices. “I am quite sure there will be some changes after the EM-1 flight. We obviously would prefer that there be a stable configuration but because of the complexity, the configuration changes to improve quality and reliability of the system.”

The Orion capsule and service module are scheduled to make their flrst flight, an unmanned mission called EM-1, on NASA’s new Space Launch System heavy-lift rocket, with a launch window of between September and November 2018.

ESA, NASA and Lockheed Martin officials had said in a May 19 briefing on the start of service module assembly that the program was so pressed for time that integration would begin even before the critical design review, on the assumption that no major issues would be found that would force a redesign.

Dettman said the early assessment is that a final “close-out” design review now set for late October to address the latest issues would allow for an April shipment to Lockheed Martin and would not, in and of itself, delay the EM-1 schedule.

Many elements of the SLS rocket are now undergoing testing of their own and there remain risks to the schedule from the launcher side as well as the Orion system.

In response to SpaceNews inquiries, service module prime contractor Airbus on June 17 said it would withhold comment on the new schedule until ESA’s Program Board for Human Spaceflight and Robotic Exploration meets to review the critical design review findings and issue a final report and recommendation.

ESA officials have said they structured the Airbus service module contract in such a way as to include margins for delays. Dettman said that because of the contract’s terms, the three-months shipment delay will have no impact on ESA’s service module program cost.