NASA is about to roll its Artemis II moon rocket back to the Vehicle Assembly Building to fix a helium flow issue that guarantees astronauts won't fly around the moon in March.

The Artemis II mission aims to send four astronauts​ — Reid Wiseman, Victor Glover, Christina Koch and Canadian astronaut Jeremy Hansen — on a flight around the far side of the moon and back.

Excess hydrogen concentration in a tail service mast umbilical interface had brought the countdown to an end during the first test.

During the lead-up to NASA’s Artemis 1 mission back in 2022, recurring hydrogen leaks led to significant delays and a cancelled launch attempt. The agency had three years to address the underlying issues with the Space Launch System (SLS) rocket’s hardware,

A NASA test to confirm repairs to seals in the SLS’s liquid hydrogen fueling system was only partially successful because of problems with ground equipment.

The space agency said Sunday it's targeting Tuesday for the slow, four-mile trek across Kennedy Space Center​, weather permitting.