The failure of the commercial flight of the Vega-C rocket due to a Ukrainian party

The failure of the first commercial flight of the European Vega-C rocket last December was due to the deterioration of a Ukrainian part in its Zefiro 40 engine, according to the conclusions of an investigation commission presented this Friday to the press by the European Space. Agency.

Le vol du 23 decembre s’est déroulé sans encombre jusque peu après l’allumage du moteur, Zefiro-40, du deuxième étage de la fusée, a explicé Pierre-Yves Tissier, a person in charge of Arianespace and co-president of the commission d’ survey.

The engine, which was supposed to run at constant pressure, registered a continuous drop in this pressure at its nozzle to the point where, three minutes and 27 seconds after takeoff, “launcher acceleration has become almost zero,” he said. Mr. Tissier.

The order to destroy the launcher, built by Italy’s Avio, was then given while Vega-C was over the Atlantic Ocean, resulting in the loss of two Airbus Earth observation satellites, Pleiades Neo 5 and 6.

unexpected thermomechanical erosion

The commission of inquiry commissioned by ESA, the launch development authority, and Arianespace, its operator, concluded that the loss of pressure was due to deterioration of the throat of the nozzle, which directs and regulates the combustion gases towards the latter. .

This mouthpiece, a carbon composite piece made by the Ukrainian Youjnoye, could not withstand the enormous pressure and temperatures that reached 3000 degrees. Mr. Tissier mentioned an “unexpected thermomechanical erosion” of this part, as a result of the inhomogeneity of its material.

The commission of inquiry did not question the design and development of the launcher. But he recommended a series of measures to ensure the future reliability of Vega-C.

ESA chief Josef Aschbacher admitted “deficiencies in the system” while pointing out a “very clear action plan” to “emerge stronger from this crisis.” Aiming for a commercial launch of Vega-C in late 2023, with the payload, to be confirmed, of the Sentinel 1-C Earth observation satellite.

This plan aims to guarantee the reliability of the nozzle throat through the use of another material, supplied by ArianeGroupe, as well as a new qualification phase of the Zefiro 40 engine. And finally, measures that guarantee the reliability of the chain supply for the manufacture of pitchers.