NASA has announced a delay for the Artemis II mission after encountering a critical issue with the Space Launch System (SLS) rocket's helium system. The problem occurred during a routine repressurization operation, preventing helium flow to the vehicle's Interim Cryogenic Propulsion Stage (ICPS).
Helium is essential for purging the upper stage engine and pressurizing its propellant tanks. While the rocket is in a secure state with a backup system active, NASA engineers are investigating the cause. A similar failure signature on the Artemis I mission in 2022 was traced to a faulty check valve.
Technicians cannot access the affected area at the launch pad. The SLS rocket will be rolled back to the Vehicle Assembly Building (VAB) for extended work platforms to provide physical access to the upper stage and its umbilical connections. This move aims to preserve the April launch window, pending the results of data analysis and repair efforts.