NASA has delayed the Artemis 2 mission’s earliest launch opportunity to March after a liquid hydrogen leak halted a wet dress rehearsal on February 3 at Kennedy Space Center in Florida.
The agency began final preparations for Artemis 2 in early January, targeting a launch window opening on February 6. The wet dress rehearsal, conducted in the early morning hours of February 3, simulates full propellant loading and countdown procedures for the Space Launch System rocket and Orion spacecraft positioned on Launch Pad 39B.
Engineers detected a liquid hydrogen leak in the Space Launch System early during the rehearsal. They spent several hours troubleshooting the issue, successfully filling all rocket tanks with cryogenic propellants, including liquid oxygen and liquid hydrogen, and resuming the simulated countdown. Approximately five minutes before the simulated liftoff time, the ground launch sequencer automatically halted operations due to a sudden spike in the spacecraft’s liquid hydrogen leak rate.
A wet dress rehearsal loads the spacecraft with actual propellants to replicate launch day conditions, verifying systems under operational stresses. NASA Administrator Jared Isaacman addressed the delay on X, stating, “With more than three years between SLS launches, we fully anticipated encountering challenges. That is precisely why we conduct a wet dress rehearsal. These tests are designed to surface issues before flight and set up launch day with the highest probability of success.” This marks the first SLS launch since Artemis 1 in November 2022, spanning over three years.
Beyond the leak, the rehearsal exposed additional anomalies. The Orion crew module’s hatch pressurization process extended longer than anticipated timelines, requiring adjustments to prevent delays on launch day. Audio communication channels for ground teams failed multiple times, disrupting coordination during critical phases.
Cold weather conditions during testing impacted mission equipment, prompting NASA to implement safeguards against similar effects during the actual launch, which could occur in variable Florida winter conditions. Ground crews now analyze comprehensive rehearsal data to pinpoint root causes across all identified problems.
Following data review, teams will implement fixes for the hydrogen leak, hatch pressurization, audio systems, and weather protections. NASA plans another wet dress rehearsal or targeted tests to verify resolutions before declaring the updated launch window, now starting no earlier than March.
