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Engineers briefly halted liquid hydrogen flow into the rocket’s core stage while teams investigated potential leaks, then resumed operations as the countdown test continued.
NASA’s wet dress rehearsal for Artemis II, a full-up countdown and fueling test meant to simulate launch day, ran into trouble Monday when engineers detected what appeared to be a leak during liquid hydrogen loading.
During the rehearsal, teams were pumping both liquid hydrogen and liquid oxygen into the Space Launch System rocket and preparing to move into a launch countdown sequence. Several hours into the operation, NASA temporarily stopped the flow of liquid hydrogen into the vehicle’s core stage, which houses the rocket’s main engines, to troubleshoot “several potential leaks,” according to the agency.
NASA said fueling resumed a short time later, with engineers working to complete fast fill, top off the tank, and keep hydrogen concentration levels within acceptable limits during core-stage loading.
Liquid oxygen continued flowing into the core stage throughout the issue. As part of the troubleshooting effort, NASA also temporarily paused liquid hydrogen loading into the rocket’s upper stage, designed to send the Orion crew capsule on its journey around the Moon.
Hydrogen leaks have been a recurring challenge in the Artemis program. Similar issues affected testing for Artemis I and contributed to launch delays lasting weeks.
Artemis II is planned as a crewed mission carrying four astronauts on a roughly 10-day loop around the Moon and back to Earth, sending humans farther into space than ever before. If the wet dress rehearsal is completed successfully, NASA has said the mission is targeting a launch date no earlier than February 8.
