Artemis II Launch Delayed After Hydrogen Leak Halts NASA Test

NASA's Artemis II mission experienced a delay following the early termination of a critical pre-launch test at Kennedy Space Center, where a hydrogen leak was detected during fueling procedures.

The wet dress rehearsal, which simulates a full launch countdown including propellant loading, was stopped five minutes before the planned end point. The decision to halt the test was made after teams identified a liquid hydrogen leak at the tail service mast umbilical interface connected to the Space Launch System (SLS) core stage.

During the rehearsal, NASA teams attempted to load cryogenic hydrogen into the SLS core stage. The leak rates at the interface exceeded allowable limits, prompting multiple troubleshooting efforts and eventual termination of the test sequence.

Following the incident, NASA reviewed the collected data and announced that the next possible launch opportunity for Artemis II will be in March 2026. Plans for a second wet dress rehearsal are now in progress to address the technical issues encountered.

What the numbers show

• The wet dress rehearsal ended at T-5 minutes before completion
• The Artemis II mission is scheduled for no earlier than March 2026
• The planned Artemis II flight will last 10 days around the Moon

NASA's Artemis II mission is set to become the first crewed lunar flyby since the Apollo 17 mission in 1972. The mission profile involves a ten-day journey around the Moon and back to Earth, marking a return to human lunar exploration after more than five decades.

The Artemis II crew includes NASA astronauts Reid Wiseman, Victor Glover, Christina Koch, and Canadian astronaut Jeremy Hansen. These astronauts are preparing for the mission as NASA works to resolve the technical challenges identified during the recent test.

NASA teams have resumed attempts to load liquid hydrogen into the SLS core stage following the initial test termination. However, leak rates at the tail service mast umbilical interface continued to surpass acceptable thresholds, resulting in ongoing troubleshooting and adjustments to the test plan.

Further updates on the Artemis II schedule and testing progress are expected as NASA completes additional assessments and prepares for another wet dress rehearsal. The agency continues to focus on ensuring all systems meet safety and performance requirements before proceeding with the crewed lunar flyby mission.

* This article is based on publicly available information at the time of writing.