NASA Discovers Helium Flow Issue in Artemis II Moon Rocket – Forcing VAB Rollback for Repairs after Successful Tanking Test: Photos

Posted On: February 22, 2026
Posted By: Ken Kremer
Comments: 0

Space UpClose view of NASA Artemis II moon rocket Orion crew module and ICPS upper stage shows location of Helium flow interruption forcing VAB rollback and launch delay to NET early April 2026. Orion umbilical’s on top. The interim cryogenic propulsion stage (ICPS) has two umbilicals. The highest, smaller ICPS forward plate includes a liquid hydrogen vent and environmental control system air line. The lower, larger aft plate supplies liquid hydrogen, liquid oxygen, and includes a helium quick disconnect and hazardous gas sensing. Credit: Ken Kremer / Space UpClose

KENNEDY SPACE CENTER, FL – Bad news for NASA Artemis II launch! An issue with interruption of highly purified helium gas flow was detected in the ICPS upper stage during testing overnight Feb. 21 at Launch Complex 39B at NASA’s Kennedy Space Center in Florida forcing rollback to the VAB.

Helium is required in various SLS systems for pressurization and purge including regulators, valves, engines and pressurizing the LH2 & LOX propellant tanks.

This issue will require NASA to rollback Artemis II rocket from launch pad 39B to VAB to make repairs – and thus launch delay from early March to the NET early April window – TBD.

https://x.com/NASAAdmin/status/2025249086908125630

This unfortunate problem comes right after NASA completed a fully successful cryogenic fueling test and simulated launch countdown test of its SLS (Space Launch System) mega moon rocket during the 2^nd attempt at a wet dress rehearsal (WDR) on Thursday, Feb. 19 at the agency’s Kennedy Space Center in Florida.

Photo of the Countdown Clock at NASA KSC press site at the conclusion of the WDR 2 tanking test on Feb. 19, 2026 – with Ken Kremer of Space UpClose witnessing the test. Credit: Ken Kremer / Space UpClose

The 4 person astronaut crew had entered quarantine but were released after the Helium issue was discovered

Rollback timing is also dependent on possible high winds forecast next few days at pad 39B NASA’s Kennedy Space Center

The approximately 4-mile trek is expected to take up to 12 hours – similar to rollout on Jan. 17.

Once back in the VAB, teams will immediately begin work to install platforms to access the area of the helium flow issue.

See below statements from NASA administrator Jared Isaacman and NASA blog post.

Details from NASA – which subsequent to the blog post confirmed rollback is required

NASA is taking steps to potentially roll back the Artemis II rocket and Orion spacecraft to the Vehicle Assembly Building (VAB) at the agency’s Kennedy Space Center in Florida after overnight Feb. 21 observing interrupted flow of helium to the SLS (Space Launch System) rocket’s interim cryogenic propulsion stage. Teams are actively reviewing data, and taking steps to enable rollback positions for NASA to address the issue as soon as possible while engineers determine the best path forward. In order to protect for troubleshooting options at both Pad B and the VAB, teams are making preparations to remove the pad access platforms installed yesterday, which have wind-driven constraints and cannot be removed during high winds, which are forecasted for tomorrow.

The upper stage uses helium to maintain the proper environmental conditions for the stage’s engine and to pressurize liquid hydrogen and liquid oxygen propellant tanks. The systems worked during NASA’s Artemis II wet dress rehearsals, but teams were not able to properly flow helium during normal operations and reconfigurations following the wet dress rehearsal that concluded Feb. 19. Operators are using a backup method to maintain the environmental conditions for the upper stage engines and the rocket, which remains in a safe configuration.

Teams are reviewing potential causes of the issue, including in the interface between ground and rocket lines used to route helium, in a valve in the upper stage, and with a filter between the ground and rocket. They also are reviewing data from Artemis I in which teams had to troubleshoot helium-related pressurization of the upper stage before launch.

A rollback would mean NASA will not launch Artemis II in the March launch window. However, the quick preparations enable NASA to potentially preserve the April launch window if a rollback is required, pending the outcome of data findings, repair efforts, and how the schedule comes to fruition in the coming days and weeks.

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