New Rocket Roadblocks Push NASA’s Moon Mission Back

NASA’s biggest space plan is facing a fresh snag. After a recent test, engineers discovered that helium – the gas used to keep fuel tanks full and clean – was not flowing properly in the upper section of the Space Launch System (SLS). Because the problem cannot be fixed on the launchpad, the rocket will have to be moved back into the Vehicle Assembly Building (VAB) for repairs. This move throws out the March launch window that was once considered likely. The setback came after a “wet dress rehearsal, ” a full fueling test that had seemed successful. During the rehearsal, launch crews dealt with hydrogen leaks that had appeared in an earlier February test by swapping seals around the propellant lines. That fix seemed to work, but the new helium issue was caught only after the test ended. NASA officials still do not know why the gas stopped flowing, and they are investigating possibilities such as a faulty filter, a misbehaving valve or problems with a quick‑disconnect line that separates the rocket from ground equipment.Because helium is essential for flushing out cryogenic fuels and keeping tanks pressurized, the absence of this gas forces NASA to use a backup method that is less reliable. The agency says any repair must happen in the VAB, where technicians can access all parts of the rocket. Moving the 3½‑million‑pound vehicle from the launchpad to the VAB is a long, delicate process that could itself introduce new stresses and even reignite hydrogen leaks. If the helium problem is solved, NASA may still need to run another wet dress rehearsal once the rocket returns to the pad. The crew – Reid Wiseman, Victor Glover, Christina Koch and Canadian astronaut Jeremy Hansen – is scheduled for a 10‑day trip around the Moon, the first crewed deep‑space journey since Apollo in 1972. Even a small delay could push the launch into April or later, and the agency is keeping options open for May and June dates. The history of the SLS shows that delays are not unusual. The 2022 Artemis I test flight was launched eight months after its first rollout, having been moved off the pad three times. The current helium issue adds another layer of uncertainty to an already complex program, and the next few weeks will determine whether NASA can keep its ambitious schedule.