The maiden flight of the new generation European heavy-duty rocket, the Ariane 6, was again rejected.
The technical challenges mean it won’t take place until the last quarter of next year, the European Space Agency (ESA) and industry officials say.
The 62-meter high three-stage Ariane 6 was due to enter service in 2020.
The delay will add to the difficulties of European satellite operators who are currently struggling to find a passage into orbit.
The predecessor Ariane 5 is no longer in production and its last three missions are fully booked.
Russian rockets are now off-limits due to Western sanctions resulting from the war in Ukraine.
It means that some leading European spacecraft will consequently have to launch on American rockets in direct commercial competition with Ariane.
ESA Director General Josef Aschbacher said the new fourth quarter target would only be valid if the outstanding technical targets were met.
“Let me really remind you that with a project of this magnitude, it needs to be clear that this is a planned date and that the program will still need to subsequently and timely achieve a number of key milestones for this program to remain viable,” he said.
The hugely successful Ariane 5 dominated the world market for launching large satellites until US entrepreneur Elon Musk introduced his cheaper and more reusable Falcon 9 rockets in the 2010s.
The 6 uses enhanced technologies and new manufacturing techniques, drastically reducing manufacturing costs, but will still be more expensive than Mr Musk’s Falcon because a new rocket is needed for each new launch.
In recent days, a test model of the Ariane 6 has been placed on its future launch pad, in Kourou, French Guiana.
The engineers hope to demonstrate the pad’s readiness and perform countdown procedures, such as loading propellants, and operating the Vulcain main engine at the base of the representative rocket.
The “real” vehicles for the first three missions are in production and key segments of the first flight model will soon be shipped to French Guiana from factories in Europe.
On 22-23 November, in Paris, ESA member states will discuss a program to improve Ariane 6 and advance reusable rocket technologies and whether Europe should fly its astronauts into space. At the moment, they have to travel on American or Russian rockets.