NASA said it was targeting a March window to launch its Artemis 2 mission to send four astronauts around the moon after a delay in this week's departure, caused by a leak of liquid hydrogen during a key "wet dress rehearsal".
The mission is the second in the multibillion-dollar Artemis moon programme, following an uncrewed flight in 2022, and the first to carry astronauts around the moon in a 10-day journey to the farthest humans have ever ventured in space.
The leak took place in an interface "used to route the cryogenic propellant into the rocket's core stage," NASA said, adding that it would release the astronauts, quarantined since January 21 for the anticipated launch.
"These tests are designed to surface issues before flight and set up launch day with the highest probability of success," NASA Administrator Jared Isaacman said in a post on X.
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.
— NASA Administrator Jared Isaacman (@NASAAdmin) February 3, 2026
With more than three years between SLS launches, we fully anticipated encountering challenges. That is precisely…
"We expect to conduct an additional 'wet dress rehearsal' and then target the March window."
The mission, crewed by three US astronauts and a Canadian, is a precursor test to the agency's first astronaut moon landing since 1972.
"With more than three years between Space Launch System (SLS) rocket launches, we fully anticipated encountering challenges," Mr Isaacman said. "That is precisely why we conduct a 'wet dress rehearsal'."
The test also saw intermittent ground audio dropouts and extended closeout operations for the mission's Orion crew capsule, he added.
