WASHINGTON — The European Space Agency says a test-firing of an Ariane 6 core stage has been postponed again, this time because of issues with ground equipment.

In an Aug. 30 update, ESA said that a planned Aug. 29 firing of the core stage of an Ariane 6 on the pad at the spaceport in Kourou, French Guiana, was postponed because of what the agency described as a “technical issue affecting the control bench” that handles propellant loading and the automated countdown.

That test, which will fire the Vulcain 2.1 engine for several seconds, has been rescheduled for Sept. 5. A longer test firing remains planned for Sept. 26, also at the spaceport.

That short-duration test was previously planned for July, but postponed when time allocated for the test ran out. ESA later explained that the automated countdown was aborted “due to certain measurements exceeding preset limits.” The agency delayed the test to late August to give teams a two-week summer break and to perform repairs to a basin used for burning off excess hydrogen that was damaged by water.

A separate test of the rocket’s upper-stage engine remains scheduled for as soon as Sept. 1 at a facility in Lampoldshausen, Germany. That test was postponed from late July because of software issues.

ESA is also moving ahead with a media briefing on Sept. 4 to update those testing efforts and other preparations for the long-delayed first launch of the Ariane 6. ESA acknowledged earlier in the month that the inaugural launch had slipped to some time in 2024, but has not provided a more specific date.

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...