WASHINGTON — The European Space Agency says a successful test firing of a redesigned Vega C solid rocket motor is a major step towards returning the rocket to flight by the end of the year.

Avio, the prime contractor for the Vega C, conducted a static-fire test of the redesigned Zefiro-40 motor May 28 at a company test facility in Italy. The motor, used as the second stage of the Vega C, fired for 94 seconds, as expected.

The Zefiro-40 was implicated in the failure of the second Vega C launch in December 2022, which an investigation blamed on faulty carbon-carbon material used in the motor’s nozzle. Avio found a new supplier for that material, but the nozzle failed in a static-fire test in June 2023, leading to a redesign of the nozzle itself.

“Initial post-test review indicates that the new nozzle assembly performed as expected throughout the scheduled 94 seconds burning time of the test, simulating a nominal in-flight performance,” Avio said in a statement.

In a May 28 interview, ESA Director General Josef Aschbacher called the successful test a key step in returning the rocket to flight. “The thrust curve that has been measured is nominal and follows the expected, theoretical line, meaning that the motor is functioning well,” he said.

A second test firing is planned for October to confirm the performance of the motor, but Ashcbacher called this test “the most important milestone” in returning the vehicle to flight. “The one today confirms that the redesign of the nozzle with the new carbon-carbon inserts is good.”

Both ESA and Avio said they are working to return the Vega C to flight by the end of the year, two years after the failure that grounded the rocket. A final flight of the original version of the Vega, which does not use the Zefiro-40, is planned for early September carrying the Sentinel-2C Earth observation satellite for Europe’s Copernicus program.

The payload for the return to flight of the Vega C is the Sentinel-1C radar imaging satellite, although Simonetta Cheli, director of ESA’s Earth observation program, said in a May 28 interview that this payload assignment had yet to be confirmed.

Aschbacher said in the interview that preparations were continuing for the first flight of the Ariane 6 in the first two weeks of July. A specific target date for the first launch attempt will be announced at the ILA Berlin air show in early June.

He said the Ariane 6 team was working through minor issues raised in a recently completed qualification review. “There is nothing that is a showstopper,” he said. “It’s still a lot of work, but nothing that worries me at this point in time that would make it impossible to launch within this two-week window.”

Jeff Foust writes about space policy, commercial space, and related topics for SpaceNews. He earned a Ph.D. in planetary sciences from the Massachusetts Institute of Technology and a bachelor’s degree with honors in geophysics and planetary science...