NASA is postponing the launch of the Artemis II mission to March, following an issue during a wet dress rehearsal at Kennedy Space Center. The rehearsal, which took place from January 31 to February 3, 2026, encountered a hydrogen leak that prompted engineers to halt the simulated launch with just over five minutes remaining on the countdown clock.
This isn’t the first time hydrogen leaks have presented a challenge for the Space Launch System (SLS) rocket. NASA gained valuable experience managing similar issues during tanking tests for the Artemis I mission in 2022. Techniques developed then were initially successful in addressing the leaks detected on February 2, 2026, allowing the wet dress rehearsal to continue after temporary halts to allow seals to reseat and propellant flow to be adjusted. However, the issue ultimately required further investigation.
The wet dress rehearsal involved a full load of propellants being loaded into the SLS rocket’s core and upper stages, and also included a replenishment process to account for cryogenic boil-off. While the rehearsal demonstrated progress compared to preparations for Artemis I, the early termination highlights the need for additional testing and review.
NASA is now targeting a launch window between March 6 and March 11, 2026, pending the outcome of a second wet dress rehearsal. This additional test will allow engineers to analyze the data from the first attempt and refine procedures to mitigate the hydrogen leak issue. The agency noted in a mission status update that engineers “pushed through several challenges” during the initial rehearsal and met many of the planned objectives.
The Artemis II mission is a crucial step in NASA’s broader Artemis program, aiming to return humans to the Moon. It is expected to be the first crewed flight to deep space since Apollo 17 in 1972. The mission will send four astronauts on a flight test around the Moon, gathering critical data for future lunar missions.
The challenges encountered during the wet dress rehearsal underscore the complexities of working with cryogenic propellants like liquid hydrogen. Maintaining the extremely low temperatures required for these fuels presents inherent difficulties, and even minor leaks can disrupt the launch process. NASA’s experience with Artemis I proved valuable in addressing these issues, and the agency is applying those lessons learned to Artemis II.
The upcoming second wet dress rehearsal will be critical in validating the effectiveness of the corrective measures implemented. Successful completion of this test will be a key indicator that NASA is ready to proceed with the launch of Artemis II and continue its ambitious program of lunar exploration.
The 67th Annual Aviation Week Laureate Awards took place on March 6, 2025, at the National Building Museum in Washington, D.C. Embry-Riddle Aeronautical University was honored at the event for its contributions to aviation and aerospace safety, specifically recognizing the Boeing Center for Aviation and Aerospace Safety for its pioneering work in advancing global aerospace safety. This recognition highlights the ongoing efforts within the aerospace industry to improve safety standards and research.
