NASA engineers found another hydrogen leak during a fueling test for the Artemis 1 moon rocket.
It appears to be a leak similar to the one that stopped the September 3rd launch.
Wednesday's test is critical to determine whether the 322-foot rocket is ready for its first test flight, a lunar-orbiting mission with mannequins in place of astronauts.
Besides replacing seals, NASA altered the fueling process, easing more slowly into the loading of the super-cold liquid hydrogen and oxygen.
Once launched, the crew capsule atop the rocket will be the first to orbit the moon in 50 years. Astronauts could climb aboard in a couple years.
Additional reporting by The Associated Press.