NASA has delayed the launch of the Artemis II lunar fly-by mission by at least a month after critical pre-launch testing uncovered multiple issues. During Monday’s wet dress rehearsal at Kennedy Space Center in Florida, teams began fueling the Space Launch System (SLS) rocket and sensors detected a hydrogen leak. After troubleshooting that initial leak, another leak appeared when the tank was pressurized.
Launch director Charlie Blackwell-Thompson said the leak “came up pretty quick” during pressurization. Hydrogen leaks also affected Artemis I in 2022, and while lessons from that uncrewed flight were applied to Artemis II, more investigation is needed.
The wet dress rehearsal revealed additional problems with the Orion capsule. A valve that pressurizes the vehicle needed extra attention, and teams took longer than expected to close the hatch while practicing spacecraft preparations without crew on board. Cold-weather effects caused camera problems, and there were audio dropouts across communications channels.
NASA administrator Jared Isaacman said on X that safety remains the agency’s top priority and that NASA will only launch when ready. Blackwell-Thompson called the day “all in all, a very successful day for us on many fronts,” while acknowledging there is “some work we’ve got to go do.”
Work now begins to address the issues, and NASA will conduct another wet dress rehearsal before approving crewed launch. The agency is targeting a March launch window, with the earliest opportunity on March 6 and additional opportunities on March 7, 8, 9 and 11.
The crew—NASA astronauts Reid Wiseman, Victor Glover, Christina Koch, and Canadian Space Agency astronaut Jeremy Hansen—were released from quarantine and will remain in Houston. They will re-enter quarantine about 14 days before the next launch attempt and travel to Kennedy Space Center six days before liftoff.
Artemis II will carry the four astronauts on a roughly ten-day mission to circle the moon and return to Earth, traveling farther into deep space than any humans have gone. The flight will test key Orion systems, including maneuverability and life support, ahead of Artemis III, which aims to return humans to the lunar surface. Artemis II would be the first crewed mission to the moon since Apollo’s final lunar mission in 1972.