- Lift off from Kennedy Space Center between 13:33 and 15:33 BST
Artemis’ test flight to the moon was thought to be back on track after a suspected hydrogen leak was fixed, but new problems could set the mission back.
Engineers discovered a possible crack in a flange in the intertank area of the center stage, but upon closer inspection, the damage was not structural and is not likely to affect launch.
Engine number three is still too hot for launch.
The original launch time was set for 8.33am ET (1.33pm BST), with a two-hour window after which the rocket can lift off, but Nasa said: “It is expected that the timeline will slip.” NASA has stopped the countdown clock 40 minutes after launch as it continues to fix the engine cooling problem.
If Artemis 1 can’t launch today, the next windows will be September 2 and 5, although there are concerns that worsening weather could affect flights as Florida heads into hurricane season .
Follow the latest updates below.