NASA's Artemis II mission faces another delay after a helium flow problem emerged in the rocket's upper stage, pushing the planned lunar trip from March into at least April. The issue surfaced just one day after NASA had targeted March 6 for the crewed mission, humanity's first return to the moon in over 50 years.

NASA Administrator Jared Isaacman identified potential causes including a faulty filter, valve, or connection plate in the Space Launch System rocket's interim cryogenic propulsion stage. The agency now plans to roll the 322-foot rocket back to the Vehicle Assembly Building for repairs, eliminating the March launch window. This setback follows earlier hydrogen fuel leaks that already delayed the mission by a month.

The helium problem is confined to the upper stage, which is critical for placing the Orion crew capsule into proper orbit and later serving as a docking target for astronaut training. This marks the second major technical issue for the Artemis program, which has only completed one uncrewed lunar flight in 2022. The first crewed moon landing under Artemis remains years away.