WASHINGTON - NASA said it's delaying until March the launch of its first crewed flyby mission to the Moon in more than 50 years, after encountering leaks during final tests.
The mishaps during a run-through that the US space agency calls a "wet dress rehearsal" dashed hopes that the mission around the Moon could launch as soon as Sunday. The next possible launch window now opens March 6.
The two-day test included filling the Space Launch System rocket with propellants, liquid hydrogen and liquid oxygen.
Teams were initially able to work through some of the hydrogen leaks they encountered, but ultimately the leak worsened as the simulated countdown reached about T-5 minutes, NASA Administrator Jared Isaacman said in a statement.
Operations were stopped, Isaacman said, adding that "we will only launch when we believe we are as ready to undertake this historic mission."
Hydrogen is particularly energetic, tiny, and difficult to contain, NASA officials told a Tuesday briefing.
Along with leakages teams had to troubleshoot a valve issue related to hatch pressurisation, in addition to dropouts of audio communications, NASA said.
The latest leaks mirror issues that delayed for months the Artemis 1 launch, which was an uncrewed test mission that ultimately circled the Moon in 2022.
John Honeycutt, head of the Artemis 2 Mission Management Team, said scientists had been "aggressive" in their testing to understand the Artemis 1 leaks.
But "on the ground, we're pretty limited as to how much realism we can put into the test. We try to test like we fly, but this interface is a very complex interface. This one caught us off guard," he continued.
"To me, the big takeaway was we got a chance for the rocket to talk to us, and it did just that," Honeycutt said.
Mission managers said they are analysing the data collected and making necessary repairs ahead of plans to run another dress rehearsal.
For now, officials said those fixes can be performed at the Florida launchpad.