NASA/Sam Lott
The sun sets on NASA’s Space Launch System (SLS) rocket and Orion spacecraft as they stand fully assembled atop the mobile launcher at Launch Pad 39B at NASA’s Kennedy Space Center in Florida, on Jan. 31, 2026.
NASA delayed the launch of its much-anticipated lunar mission Artemis II until at least March 6, after a dress rehearsal of launch-day procedures yielded problems.
A liquid hydrogen leak was found in the space launch system’s core stage, the main part of the rocket. Though crews were ultimately able to fill the rocket with liquid hydrogen and carry on with much of the dress rehearsal, the leak began to increase in the final minutes of the rehearsal.
Now, NASA is no longer moving forward with a February launch, Administrator Jared Isaacman announced in the early hours of Tuesday morning.
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With the conclusion of the wet dress rehearsal today, we are moving off the February launch window and targeting March for the earliest possible launch of Artemis II.
With more than three years between SLS launches, we fully anticipated encountering challenges. That is precisely…
— NASA Administrator Jared Isaacman (@NASAAdmin) February 3, 2026
“As always, safety remains our top priority, for our astronauts, our workforce, our systems, and the public,” Isaacman said in a post on X. “As noted above, we will only launch when we believe we are as ready to undertake this historic mission.”
The days-long dress rehearsal runs through launch procedures beginning about two days in advance, leading up to about 30 seconds until the launch. During the dress rehearsal on Monday, crews were able to count down to about 5 minutes before the simulated launch, until the leak became too prevalent.
Beyond the leak, Isaacman said other factors also contributed to the delay, including “intermittent ground audio dropouts, and cold-weather impacts to some cameras.”
NASA will plan to conduct another dress rehearsal for Artemis II prior to a potential March launch. The available days to launch next month are March 6, 7, 8, 9, and 11. Should another dress rehearsal prove unsuccessful, the launch will be delayed to April.
Officials with NASA are expected to hold a pre-planned press conference in Cape Canaveral later on Tuesday.
Artemis II is anticipated to be a 10-day mission for four astronauts to leave the Earth, orbit the moon, and go further than humans have ever gone before. Though the crew will not land on the moon, it will be the first time humans have left Earth’s orbit in more than half a century.