The US space agency on Monday scrubbed the uncrewed Space Launch System (SLS) Moon mission called Artemis I owing to a technical engine glitch.
NASA said in a tweet that the launch was currently in an unplanned hold as engineers spotted an issue with one of the rocket's engines.
"The team works on an issue with engine number 3 on the @NASA_SLS core stage," said the space agency.
NASA will issue another launch date at a later stage.
Artemis I will go into deep space and will perform a long orbit around the Moon before coming back to Earth.
It will lay the foundation for a sustained long-term presence on and around the Moon.
The US space agency last week identified 13 candidate landing regions near the lunar south pole, as it prepares to send humans back to the Moon under the Artemis programme in 2024.
Each region contains multiple potential landing sites for Artemis III, which will be the first of the Artemis missions to bring crew to the lunar surface.
