NASA disclosed a fresh technical snag with its moon-bound rocket Saturday, casting serious doubt on next month’s crewed liftoff. The issue struck the upper stage of the 98-meter Space Launch System just one day after officials locked in a March 6 target date for the first lunar flight with humans in over 50 years.

Engineers detected the helium flow stoppage overnight. Solid helium delivery powers key systems in that stage, officials said. The glitch stands apart from hydrogen fuel leaks that derailed a dress rehearsal earlier this month and prompted a redo.

Teams now sift through data at Kennedy Space Center in Florida. NASA weighs two paths: repairs right at the pad or rolling the giant rocket back to the hangar. "This will almost assuredly impact the March launch window," the agency stated.

The four-person crew—Commander Reid Wiseman, Pilot Victor Glover, Mission Specialist Christina Koch and Canadian Jeremy Hansen—entered a two-week quarantine Friday night. The isolation shields them from infections before flight. A second fueling test Thursday showed minimal leaks, boosting hopes for March until this helium hitch surfaced.

The problem isolates to the interim cryogenic propulsion stage atop the SLS core. That section sends the Orion capsule into a high Earth orbit for systems checks after launch. Orion then detaches, turning the stage into a mock target. Astronauts inside practice docking moves needed for later lunar outings.

Artemis II marks a crewed flyby of the moon, no landing. It builds on the uncrewed Artemis I mission in late 2022, which looped the moon successfully despite its own hydrogen woes pre-launch. Hydrogen leaks also pushed Artemis II back a month already.

NASA’s Apollo era sent 24 astronauts moonward from 1968 to 1972. Artemis aims to return humans there, with a crewed landing eyed no sooner than 2026 or later. Managers stress steady progress amid these hurdles. The rocket sits fueled on Launch Pad 39B, ready for whatever fix comes next.

Engineers prioritize quick resolution. Pad work could preserve the schedule. A hangar trip means more delays. NASA updates will follow data review, officials said. The mission tests Orion’s deep-space chops before riskier steps ahead.