ESA blames eroded nozzle for Vega-C rocket failure

The European Space Agency (ESA) announced the results of a months-long investigation of failed launch of the Vega-C rocket back in December, pointing to a malfunction with an engine component as the cause behind the catastrophic anomaly.

The The Independent Commission of Inquiry shared the results of its investigation on Friday, revealing that the reason behind the mission failure was a gradual deterioration of the Vega-C second stage nozzle, ESA wrote in a statement.

Vega-C took off on December 20, 2022 from Kourou Stempo center in French Guiana, with the Neo 5 and Neo 6 satellites for Airbus’ Pleiades Neo Earth-forming constellation. About two minutes and 27 seconds after liftoff, the rocket’s second stage, called Zefiro 40, experienced a reduction in pressure and the mission was terminated. The rocket, developed by ESA, built by the Italian company Avio, and operated by Arianespace, failed to reach orbit and the payload was destroyed.

According to the results of the investigation, the throat insert of the Zefiro 40’s nozzle — the part of the engine where the hot exhaust exits the combustion chamber — suffered from a “thermo-mechanical over-erosion,” the ESA wrote. As the throat insert eroded, the chamber pressure dropped, causing a reduction in the rocket’s thrust. The commission concluded that the material that makes up the neck insert, a specific type of carbon-carbon (CC), would no longer be used for flight and that the collapse “was probably due to an error in the homogeneity of the material,” ESA wrote. Aviation purchased this in error part from Ukraine.

“Taking into account the nature of the VV22 anomaly, the Commission emphasizes that the conclusions on Zefiro 40 do not affect the Vega rocket,” ESA wrote in its statement. “In this context, Arianespace decided to adjust its launch schedule to redeploy a mission to one of the two remaining Vega launches with a targeted launch date before the end of summer 2023.”

Vega-C debuted in July 2022, taking off for the first time from the space agency’s launch facility in Guyana. The medium launch vehicle was hailed as a worthy successor to the small one Vega launcher, which was in operation for ten years. The European space industry as a whole counted on Vega-C to provide some kind of local access to Earth track, deliver payloads and maintain Europe’s presence in industry.

The rocket’s second go at ascent may not have gone as planned, but ESA and Arianespace are ready to see Vega-C fly again.

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