The European Space Agency posted an update Friday on the status of its flagship rocket, the Ariane 6 vehicle. While the space agency did not provide a concrete launch target for the rocket's debut flight, it shared information on key milestones to be completed, including a test firing of the rocket's first stage in French Guiana.

Even without an updated launch date, it can reasonably be inferred from the new information that the Ariane 6 rocket will not launch this year. The question now is how far the debut of the much-anticipated rocket will slip into 2024.

Here's why: During a news conference in October 2022, the director general of the European Space Agency, Josef Aschbacher, laid out the pathway for the Ariane 6 rocket to make its debut in 2023. "There are three very big milestones ahead of us that need to be accomplished by the first quarter of 2023 in order for the inaugural flight by the end of next year," he said at the time.

The three milestones he cited were: two wet-dress rehearsals and a hot fire test of a non-flight version of the Ariane 6 first stage at the launch site in French Guiana; the initiation of a "unified qualification review" of the rocket and its ground systems; and completion of a campaign to test fire the rocket's upper stage in Germany.

In its Friday posting—and to be clear, we are midway through the second quarter of 2023—the European Space Agency provided an update on these three milestones.

• Starting May 2023: Ground combined test sequence at Europe’s Spaceport in French Guiana. This test sequence notably includes two wet rehearsals and a long firing test of the lower stage on the launch pad. The successful achievement of this sequence is a main prerequisite for the inaugural flight.
• Starting late June 2023: Overall launch system qualification review. Unified qualification review of the launcher, launch system, and launch base.
• Early July 2023: Upper stage additional test at DLR Lampoldshausen, Germany. This test on the P5.2 test bench will simulate a nominal flight profile like the one planned for the inaugural flight to confirm the expected behavior of the upper stage. A further test is planned to examine stage behavior in degraded cases.

So in the best-case scenario, it seems likely that the European Space Agency and the rocket's developer, ArianeGroup, could complete these milestones by the end of the third quarter of this year. Assuming there is still a nine-month period between their completion and the inaugural flight of the Ariane 6, we can set a "no earlier than" launch date for the rocket in the second quarter of 2024. More realistically, the launch will occur sometime next summer.

In response to a query about a target date for the Ariane 6 rocket's debut, a European Space Agency spokesperson told Ars that it will be provided later this year.

"As you can see from our update, several key milestones have to be completed before a target launch date can be confirmed," the agency said in an emailed statement. "We expect we will be able to provide this date by the end of summer 2023. In the meantime, together with our partners, we will provide regular updates on Ariane 6’s progress toward its inaugural flight so that you know exactly where we stand."

The development of the Ariane 6 rocket is a matter of some urgency for Europe, which has set "independent access to space" as a priority. However, the Ariane 5 rocket will make its final flight before retirement in June, leaving the continent without a medium-lift launch capability. It's likely that the European Space Agency will have to resort to buying launches from its competitor, SpaceX, for institutional satellite launches.

There has been some criticism that Europe did not innovate enough with the design of its Ariane 6 rocket when the vehicle was conceived in 2014. The booster is largely an update of Ariane 5 technologies, with an eye toward reducing costs, rather than a major step toward a reusable booster like the Falcon 9. However, if the rocket had arrived by its original target in 2020, it would find no shortage of customers given the current lack of launch capacity in the Western world.

Instead, the Ariane 6 will now be about four years late and compete against a new generation of rockets with varying levels of reuse and cost competitiveness—including Rocket Lab's Neutron vehicle, United Launch Alliance's Vulcan, SpaceX's Starship, Blue Origin's New Glenn, Relativity Space's Terran R, Japan's H3 rocket, and more. In other words, had ArianeGroup executed on the development of Ariane 6, it could have gotten the jump on all of these vehicles and been the West's alternative to the Falcon 9.

Now, it represents a missed opportunity.