Credit: Avio

PARIS — The prime contractor of the European Vega rocket that failed in July, resulting in the loss of a United Arab Emirates reconnaissance satellite insured for $413 million, said a manufacturing defect in the rocket’s second-stage motor might be the root cause of the failure.

A European government board of inquiry concluded that a “thermal/structural” failure of the rocket’s Z23 second stage motor’s forward dome is the most likely cause. But the board’s Sept. 5 statement on the preliminary results of its inquiry was too vague to draw many conclusions:

In a Sept. 12 conference call with investors, Vega prime contractor Avio SpA said that while the precise mechanism that led to the failure was not yet known, there is the “possibility of an undetected non-compliance in production.”

The inquiry board said it found no evidence of poor workmanship or any design issues in the Z23 stage or its carbon-fiber forward dome. It suggested that it had reviewed all the documentation related to the flight hardware.

But the inquiry board said it would ask Vega contractors to reinforce multiple elements and present its work to the inquiry board in view to a return to flight in the first three months of 2020.

Avio Chief Executive Giulio Ranzo did not say the company had found on its own any indications of a manufacturing defect in the forward dome.

He said the temperatures and pressures that the hardware must withstand are severe, but that both Avio and the inquiry board had validated the dome’s design.

“We will develop a validation plan with subsystem tests and inspections and further engineering analyses,” Ranzo said. “This will help refine details of the causes of the failure.

“We have agreed to implement corrective actions in these subsystems on certain processes and certain equipment linked  directly to the failure mechanism, to make this motor more robust.”

Ranzo said a meeting with the inquiry board and the 22-nation European Space Agency (ESA), which oversaw the inquiry, will be held to verify that the corrective actions are implemented. He said the hardware for Vega’s next flight — in particular the Z23 stage — will be sent to Europe’s Guiana Space Center before the end of the year.

Credit: Avio

The failure’s cost to Avio and the broader Vega contracting team is yet to determine. Ranzo said it’s possible that part of the cost would be covered by ESA. Avio has prudently decided to commit to only 5 million euros ($5.7 million) of its approved 9-million-euro share-buyback plan to keep cash available if needed.

Assuming a return to flight by March, he said the inaugural flight of the more-powerful Vega C rocket would occur by June. It’s possible that there will be a second Vega flight before the introduction of Vega C.

Launch-service provider Arianespace has yet to settle on a 2020 manifest for Vega.

For the six months ending June 30, Avio reported a net profit of 7.1 million euros, up 14% from the same period a year ago. Revenue was up 6%, to 189 million euros.

Ranzo said that Vega production is only about 25% of Avio’s revenue, with the remaining 75% coming from production of components for the heavy-lift Ariane 5 rocket and development work related to Vega C and the Ariane 5 replacement, Ariane 6, whose inaugural flight is scheduled for late 2020.