A hydrogen fuel leak interrupted the launch countdown for NASA's new moon rocket early Monday morning, further delaying the operation that was already running late because of a thunderstorm offshore.
The leak reappeared in the same place as a leakage from a countdown test earlier this year.
Launch controllers slowly resumed to determine weather the leak may worsen, which would likely end the countdown. Alarms then prompted another stoppage.
The rocket is the most powerful one built my NASA, even beating out the Saturn V that astronauts rode to the moon 50 years ago.
The NASA moon rocket stands ready less than 24 hours before it is scheduled to launch on Pad 39B for the Artemis 1 mission to orbit the moon at the Kennedy Space Center, Sunday, Aug. 28, 2022, in Cape Canaveral, Fla. (AP Newsroom)
If this test flight is successful, it would put a crew capsule into lunar orbit for the first time in half a century.
The Orion capsule atop the rocket at NASA's Kennedy Space Center does not have any astronauts inside, but it is carrying three test dummies. The lunar-orbiting mission is expected to last six weeks.
Thousands of people flocked to the coast to witness the Space Launch System rocket liftoff. Vice President Kamala Harris and Second Gentleman Douglas Emhoff traveled to Cape Canaveral for the launch.
Hydrogen fuel leaks impacted NASA's countdown test in April, resulting in numerous repairs. Another test in June had more success, but still experienced some leakage.
Storm clouds roll in over the NASA moon rocket as it stands ready for launch on Pad 39B for the Artemis 1 mission at the Kennedy Space Center, Saturday, Aug. 27, 2022, in Cape Canaveral, Fla. The launch is scheduled for Monday morning Aug. 29. (AP Ph (AP Newsroom)
Managers said they would not be able to ensure the fixes were good until trying to load the rocket's tanks with nearly 1 million gallons of super-cold fuel on Monday.
There was also an 11-minute delay in the communication lines between Launch Control and Orion late Sunday. The issue was resolved by Monday morning, but NASA still had to figure out why it happened before the launch could can place.
The NASA moon rocket stands ready less than 24 hours before it is scheduled to launch on Pad 39B for the Artemis 1 mission to orbit the moon at the Kennedy Space Center, Sunday, Aug. 28, 2022, in Cape Canaveral, Fla. (AP Photo/John Raoux) (AP Newsroom)
If the test launch is successful, astronauts would ride in the second flight and soar around the moon and back as soon as 2024. A two-person lunar landing could happen by the end of 2025.
The Associated Press contributed to this report.