NASA announced Tuesday it has delayed the Artemis II mission, the first crewed lunar flyby in over 50 years, to at least March following a liquid hydrogen leak during a critical fueling test.
The issue emerged during a wet dress rehearsal of the Space Launch System rocket at Kennedy Space Center. The rehearsal, which simulates launch countdown procedures including propellant loading, was terminated early due to the leak.
Agency officials stated that the delay allows time for data review and a second test, shifting the potential February launch to prioritize safety for the four-astronaut crew.
The wet dress rehearsal began Monday but was delayed due to cold weather, according to NASA.
Engineers detected the leak at the tail service mast umbilical interface during liquid hydrogen loading.
“The Artemis II wet dress rehearsal countdown was terminated at the T-5:15 minute mark due to a liquid hydrogen leak at the interface of the tail service mast umbilical, which had experienced high concentrations of liquid hydrogen earlier in the countdown, as well,” the agency reported in a blog post.
NASA Administrator Jared Isaacman addressed the setback in a statement. “With the conclusion of the wet dress rehearsal today (Tuesday), we are moving off the February launch window and targeting March for the earliest possible launch of Artemis II,” he said, per Reuters.
Isaacman elaborated on social media. “With more than three years between SLS launches, we fully anticipated encountering challenges,” he posted on X.
“That is precisely why we conduct a wet dress rehearsal. These tests are designed to surface issues before flight and set up launch day with the highest probability of success,” he added.
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
Possible March launch dates include March 6, 7, 8, 9, and 11, according to Houston Public Media.
The mission will send NASA astronauts Reid Wiseman, Victor Glover, and Christina Koch, along with Canadian Space Agency astronaut Jeremy Hansen, on a 10-day journey around the Moon and back, testing the Orion spacecraft.
Artemis II follows the uncrewed Artemis I in 2022 and precedes Artemis III, planned for a lunar landing no earlier than 2027. The program aims to enable sustainable moon exploration, with SLS standing 322 feet tall and delivering 8.8 million pounds of thrust.
No injuries were reported during the rehearsal, and teams are assessing the hardware. NASA has not set a firm launch date pending the next test.
