Just a day after its successful dress rehearsal, NASA found a critical issue with the Artemis II's rocket, which will require rolling the rocket away from the launch pad and back into its assembly building, the federal space agency announced Saturday.
NASA administrator Jared Isaacman said the agency would “take the March launch window out of consideration,” meaning NASA’s first mission to the moon in more than 50 years is expected to be delayed until early April as a result.
Overnight on Saturday, engineers found "interrupted flow of helium" into the rocket's interim cryogenic propulsion stage (ICPS), which provides propulsion to the Orion spacecraft while the astronauts are in space. NASA says helium flow is required for launch.
As such, Isaacman said the Artemis II will be rolled away from the launch pad in Cape Canaveral, Florida, where it's been for several weeks, and back to NASA’s nearby Vehicle Assembly Building for troubleshooting.
As an update to my earlier post.
– The ICPS helium bottles are used to purge the engines, as well as for LH2 and LOX tank pressurization. The systems did work correctly during WDR1 and WDR2.
– Last evening, the team was unable to get helium flow through the vehicle. This... https://t.co/Qte3nEXwQb
— NASA Administrator Jared Isaacman (@NASAAdmin) February 21, 2026
“I understand people are disappointed by this development,” Isaacman said in a social media post on Saturday. “That disappointment is felt most by the team at NASA, who have been working tirelessly to prepare for this great endeavor.”
It's a notable setback for Artemis II, which had just had a successful dress rehearsal on Thursday. Engineers were able to fill the rocket with several hundred thousand gallons of propellant, prompting the agency to move forward with a March 6 launch date.
Isaacman added that the ICPS helium system performed correctly during both this dress rehearsal and the one earlier this month, when there was a liquid hydrogen fuel leak, pushing back the initial potential launch dates that had been set for February.
"This was an unexpected development during routine helium flow operations last evening," Isaacman said Saturday. "The teams were up all night assessing the situation."
Rolling Artemis II back to the Vehicle Assembly Building (VAB) is a day-long process, as is rolling the rocket back out to the launch pad. NASA had initially said it was preparing to troubleshoot the problem at both locations, though Isaacman clarified that by saying, “Regardless of the potential fault, accessing and remediating any of these issues can only be performed in the VAB.”
The four astronauts on the Artemis II mission, which aims to send them around the moon and back to Earth, entered their quarantine Friday evening in Houston. It's not immediately clear if they will remain in quarantine for the next two weeks as originally planned.
If the launch does not happen by March 11, NASA has said it will not happen until April 1. Isaacman said he planned to hold a briefing about the Artemis II mission and other lunar missions in the coming days.
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