NASA rules out March lunar launch following SLS helium flow failure

NASA Administrator Jared Isaacman has officially ruled out a March launch window for the Artemis II mission due to an interruption in helium flow within the Space Launch System (SLS) interim cryogenic propulsion stage. The towering rocket and Orion spacecraft will be rolled back to the Vehicle Assembly Building at the Kennedy Space Center in Florida for troubleshooting, abandoning the previously targeted March 6 launch date.

The anomaly occurred overnight during a routine repressurization operation. While the helium systems — essential for engine purging and pressurizing liquid hydrogen and liquid oxygen tanks — functioned correctly during recent wet dress rehearsals, the team suddenly lost flow to the vehicle. The spacecraft remains in a safe configuration using a ground purge system. Potential hardware faults include a failed final filter, a quick-disconnect umbilical interface, or an onboard check valve. The latter would mirror a failure signature previously observed during the uncrewed Artemis I mission, which launched in November 2022 after its own series of delays.

Artemis II, an expected 10-day expedition featuring three Americans and one Canadian, represents the first crewed lunar flyby in more than 50 years. The program has encountered multiple scheduling setbacks, including a liquid hydrogen leak in early February that prematurely ended a wet dress rehearsal.

Addressing the current setback, Isaacman drew historical parallels to the Apollo era, noting that Neil Armstrong's Gemini 8 mission ended prematurely due to technical faults just years before his historic moonwalk. The Artemis program, initiated during President Donald Trump's first term, serves as a critical stepping stone toward establishing a continuous lunar base and eventually conducting crewed missions to Mars. A comprehensive technical briefing detailing the path forward is expected later this week.