The US space agency NASA plans to fly three Americans and one Canadian to the Moon - which would be the first crewed lunar mission since the final Apollo mission in 1972. However, the mission, named Artemis 2, does not involve a landing, but only a crewed flight to the Moon.
According to the NASA chief, problems with the rocket's helium flow are delaying the launch.
"I understand that people are disappointed by this development," wrote Jared Isaacman on X.
The announcement is a setback for the United States in the race with China and others to be the first country to carry out a crewed lunar mission again.
The next possible launch date is in April at the earliest.
What do you think?