Cape Canaveral, FL – NASA is preparing to roll back the Space Launch System (SLS) rocket and Orion spacecraft to the Vehicle Assembly Building (VAB) at Kennedy Space Center, effectively delaying the Artemis II mission. The decision comes after an interruption in helium flow within the rocket’s interim cryogenic propulsion stage (ICPS) was detected overnight on Saturday, February 21, 2026, jeopardizing the planned March launch window.
The issue with the ICPS has prompted a review of data and contingency planning, with a potential April liftoff now the target, pending the outcome of repairs. NASA Administrator Jared Isaacman addressed the development, emphasizing the troubleshooting efforts underway. This setback underscores the complexities of returning humans to the Moon, even with decades of experience from the Apollo program.
Helium plays a critical role in the SLS upper stage, being used to purge the engine and pressurize propellant tanks. Fortunately, the rocket is currently in a “safe configuration,” with a backup system providing purge air to the upper stage, according to NASA officials. The Artemis II mission is designed to carry four astronauts around the far side of the Moon and back to Earth, representing a significant step in NASA’s long-term lunar exploration goals.
Similar Issue Encountered During Artemis I
This isn’t the first time NASA has faced a similar challenge with the SLS. A comparable failure signature was observed during preparations for the Artemis I mission in 2022. In that instance, engineers traced the problem to a failed check valve on the upper stage, requiring a replacement. NASA Spaceflight reports that officials are currently investigating whether the current helium issue stems from a similar valve failure, a problem with the umbilical interface connecting the rocket to the launch tower, or a fault within a filter.
Accessing and resolving the issue at the launch pad is proving impossible, necessitating the rollback to the VAB. Inside the VAB, ground teams will be able to extend work platforms around the rocket, providing the necessary physical access to the upper stage and its associated umbilical connections.
April Launch Window Remains Possible
NASA is proactively preparing for the rollback to potentially preserve the April launch window. Whereas, this is contingent on the findings of the ongoing data analysis, the success of repair efforts, and the overall schedule in the coming weeks. WION News reports that NASA Administrator Jared Isaacman confirmed the rocket will be removed from the launchpad for repair work.
It remains unclear whether NASA will conduct another fueling test after the SLS returns to Launch Pad 39B. There’s similarly uncertainty regarding further work on the hydrogen umbilical, which has been a source of recurring leaks during both the Artemis I and Artemis II campaigns. While managers were encouraged by the performance of newly installed seals during a countdown demonstration on Thursday, February 20, 2026, NASA officials have previously cautioned that vibrations from transporting the rocket could potentially damage those seals.
Hydrogen Leaks and Ongoing Challenges
Fuel leaks have been a recurring issue for the Space Launch System. Ars Technica notes that the same type of leak delayed the first test flight of the SLS rocket in 2022. Ground teams addressed that issue by modifying the hydrogen loading procedure, but the leak reappeared during a February 2, 2026 test. Engineers have traced the hydrogen leaks to ground support equipment, specifically in the area where fueling lines connect to the core stage.
Isaacman acknowledged the challenges, stating, “Considering the issues observed during the lead-up to Artemis I, and the long duration between missions, we should not be surprised there are challenges entering the Artemis II campaign.” He also expressed confidence in the NASA team and its contractors working diligently to resolve the issues.
The helium system on the ICPS reportedly performed well during both Wet Dress Rehearsals (WDRs) – full-scale fueling simulations conducted at Launch Pad 39B – according to NASA Spaceflight. This highlights the unpredictable nature of complex spaceflight systems and the importance of thorough testing and redundancy.
What comes next involves a detailed assessment of the helium system, repairs within the VAB, and a careful evaluation of the schedule. NASA will likely provide a more comprehensive briefing outlining the path forward for Artemis II and subsequent missions. The agency remains committed to its ambitious lunar exploration program, but these challenges demonstrate the inherent risks and complexities of space travel.
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