NASA delays Artemis II moon launch to March after hydrogen leaks

NASA announced on Feb. 3, 2026, that it would not try to launch Artemis II until at least March after it was unable to complete a wet dress rehearsal for the mission at Launchpad 39B at the Kennedy Space Center in Florida. The two-day rehearsal, which began on Sunday, involves filling the Space Launch System rocket’s tanks with millions of pounds of liquid hydrogen and liquid oxygen.

No astronauts were aboard and the engines would not ignite; the countdown was to run to about half a minute. Leaks of hydrogen occurred during fueling, echoing problems that delayed the Artemis I uncrewed flight in 2022. Mission managers ran hours behind schedule on Monday and were able to fill the propellant tanks, allowing the countdown to proceed into the last 10 minutes.

The hydrogen leak reappeared and the rehearsal was scrubbed shortly after midnight with about five minutes left. NASA administrator Jared Isaacman wrote on social media that with more than three years between SLS launches the agency expected challenges and that wet dress rehearsals are meant to surface issues before flight.

NASA said the hydrogen leak required pauses to let seals warm up and adjustments in the rate of propellants flowing into the rocket. Other problems during the countdown included a loose valve and dropouts in audio communications.

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