Space News by Jeff Foust March 3, 2023
Europe plans to return the Vega C rocket to flight by the end of the year after concluding an eroded nozzle component caused the failure of its previous launch last December.
The European Space Agency announced March 3 it had completed an independent investigation into the failed Dec. 20 launch of the Vega C on the VV21 mission, which experienced a loss of thrust from its Zefiro-40 solid-fuel second stage. The failure resulted in the loss of two Pléiades Neo imaging satellites for Airbus Defence and Space.
The investigation concluded that a component in the motor called a throat insert, made of carbon-carbon material designed to withstand high temperatures, suffered “thermo-mechanical over-erosion” during the launch. That insert regulates the flow of exhaust through the nozzle, and as it eroded the chamber pressure dropped, causing thrust to decrease.
By 207 seconds after liftoff, or a little more than a minute after the second stage ignited, acceleration of the vehicle became “quasi-null” and put the rocket on a ballistic trajectory, said Pierre-Yves Tissier, chief technical officer of Arianespace and co-chair of the independent investigation, in a briefing about the report. A fault tree analysis led investigators to rule out other causes of the failure.
The erosion of the insert, he said, was linked to higher porosity of the carbon-carbon material, confirmed in other testing of the material but not detected earlier. “The acceptance criteria established for this material were not able to detect such a weakness,” he said.
More:
https://spacenews.com/nozzle-erosion-blamed-for-vega-c-launch-failure/
