A Zefiro 40 motor encountered an abnormality during a test as part of an effort to requalify the motor after the rocket failed on its second flight in December 2022, according to a statement released by Avio, the Italian company that is the Vega’s primary contractor, on June 29.

The goal of the static-fire test was to show how well the new carbon-carbon material in the motor’s nozzle throat performed. After a similar material from a Ukrainian supplier deteriorated and caused a loss of thrust during a Vega-C launch in December 2022, Avio replaced that material. The Zefiro 40 serves as the second stage of that rocket.

The novel carbon-carbon material performed as predicted, according to Avio. However, 40 seconds into the fire, an unidentified aberration occurred. Prior to the 97-second firing period coming to a conclusion, this led to a decrease in pressure in the motor. The nature of the anomaly or performance loss was not further described by the company.

The business said, “This aspect will require further investigation and testing activity to be conducted by Avio and the European Space Agency to ensure optimal performance conditions,” and it will be days or weeks before the study into the anomaly is finished.

Josef Aschbacher, director general of the European Space Agency (ESA), said at a press conference following a meeting of the ESA Council on June 29 that “we have to see in detail what this anomaly will mean” for the Vega-C. This will have an effect because it was a crucial checkpoint on the road to Vega-C’s return to flight.

One of the crucial phases in the process of getting the Vega-C back in the air was the test. When the study into the launch failure was finished in March, Avio added that it would conduct a more thorough evaluation of the vehicle’s supply chain to check for any more potential problems.

On the first iteration of Vega, the Zefiro 40 is not utilised. In September, Avio stated it would start up its Vega launches once more. Prior to the test accident, the Vega-C was scheduled to launch the Copernicus program’s Sentinel-1C radar imaging satellite on its subsequent mission in the latter part of this year.

Due to this event, it is less likely that Vega-C will resume flying this year, but Avio made no comments regarding a revised timeline. “The planning for the return to flight of Vega-C is currently under evaluation, pending further analysis and investigation,” Avio stated in the statement.

Aschbacher said that the ESA Council approved a request from the inspector general to switch the launch of the EarthCARE spacecraft, a mission to study the Earth, from Vega-C to Falcon 9. He claimed that was related to both the December 2022 launch failure and changes in EarthCARE’s design that would have necessitated modifying the Vega-C payload fairing to accommodate them. The debut of EarthCARE is planned for 2024.