The artemis 1 rocket fueling test hit another snag on Wednesday morning after a leak like the ones that had delayed previous launch attempts.
NASA said its mission managers had detected a liquid hydrogen leak at the eight-inch quick disconnect seal between the tail service mast and the rocket.
The launch director signed off on a plan to warm up the line to try and reset the connection point.
The flow of liquid hydrogen into the core stage resumed in the fast-fill stage.
The engine kickstart bleed test on the main engines was completed by NASA.
More than five hours into the cryogenic demonstration test and after the core stage liquid oxygen was replenished, the agency said that the hydrogen leak remained manageable during the test.
We are in replenishing liquid hydrogen fast fill and we are complete in the core stage. The hydrogen leak is at 0.5%, according to NASA Exploration Ground Systems.
The teams heated up the quick disconnect umbilical line and the leak then maxed out at 3.4%, which is within the acceptable range to continue, the team said.
Teams were moving ahead with operations to load propellants into the interim cryogenic propulsion stage of the rocket.
The pre-press test was scheduled to occur after the liquid hydrogen and liquid oxygen loading on the stage reached the replenish phase.
The pre-pressurization test will bring the liquid hydrogen tank up to the pressure level it will experience just before launch, while engineers calibrate the settings for conditioning the engines at a higher flow rate, as will be done during the terminal count on launch day, NASA said in a blog post.
The upper stage of the Space Launch System was loaded minutes later, according to NASA spokesperson Derrol Nail.
The wet dress rehearsal is a critical step to make sure the rocket is ready for its test flight.