WASHINGTON — Europe’s Ariane 6 rocket has completed a fueling test and countdown rehearsal that is the final major milestone before its inaugural launch in July.

The European Space Agency said June 21 that the agency and its partners completed a wet dress rehearsal the previous day at the launch site in French Guiana. In the test, the rocket was loaded with liquid oxygen and liquid hydrogen propellants and went through a countdown that stopped just before engine ignition.

“The wet dress rehearsal is the very final milestone before launch,” said Guy Pilchen, Ariane 6 launcher project manager at ESA, in a statement. The test, a common one for new launch vehicles, allows vehicle teams “to fine-tune the delicate operations required up until liftoff, using the real rocket’s actual flight hardware and software for the first time,” he noted.

The test was originally scheduled for June 18 but delayed two days. ESA officials said at a June 19 briefing after a meeting of the ESA Council that the slip was not linked to any major problems and would not delay the vehicle’s inaugural launch, announced earlier in the month for July 9.

“The preparations towards the inaugural flight are really, really progressing well,” ESA Director General Josef Aschbacher said at that briefing. That included a closeout of remaining issues from a qualification review of the vehicle, completed June 14, and installation of the payloads and fairing on the rocket’s upper stage the same day.

“There is no showstopper, so everything proceeds nominally, but there is still, of course, a lot of work to be done towards the inaugural flight,” he said.

The ESA statement about the completion of the wet dress rehearsal added that analysis of data from it would continue to June 26. ESA has also scheduled a series of media briefings June 25 to discuss pre-launch preparations.

Ariane 6 is critical to efforts by ESA to end a “launcher crisis” that has temporarily deprived Europe of independent access to space. Several factors caused the crisis, such as delays in the development of Ariane 6 that pushed its introduction to after the final launch of the Ariane 5 nearly a year ago, problems with the Vega C rocket that have sidelined the vehicle since a failure a year and a half ago, and loss of access to the Soyuz rocket after Russia’s invasion of Ukraine more than two years ago.

ESA announced in November 2023 an agreement for “stabilized exploitation” of the Ariane 6 and Vega C that included providing 340 million euros ($364 million) a year of financial support for the Ariane 6. That agreement requires the companies developing Ariane 6 to reduce their costs by 11%.

“We are on track for that,” Aschbacher said of that reduction at the briefing. “Lots of discussions have taken place with some of the key suppliers,” he added, with “good progress in the last couple of days.”

“We are making steady progress,” said Toni Tolker-Nielsen, ESA’s director of space transportation, regarding that cost reduction. He said an unnamed German partner on the vehicle had agreed to implement that price cut, “so that’s a major step ahead.”

The November 2023 agreement also called for transferring the responsibility for Vega C launch services from Arianespace to Avio, the prime contractor for the rocket. Avio executives said last month that discussions about that transfer were still in progress.

Aschbacher said that ESA had been called in to mediate negotiations between the two companies in recent weeks on the agreement to hand over Vega C operations at the request of one of the companies. “The conditions for the transfer of Vega C from Arianespace to Avio are clear,” he said. “We have made enormous progress and are very close, I would say, to having closed the open items.” He did not elaborate on the issues that required ESA’s mediation.

The ESA Council was scheduled to take up a resolution approving that transfer at the meeting that concluded June 19, but Aschbacher said the council will instead hold an separate meeting by the end of the month to finalize the transfer.

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...