The National Aeronautics and Space Administration (NASA) conducted a comprehensive drill on the "Artemis 2" manned mission around the moon on the 2nd, covering key aspects such as propellant filling and launch countdown. However, the countdown program was suspended due to a leak of liquid hydrogen from the propellant interface of the rocket's core stage.NASA Administrator Bill Nelson later said that the mission launch window would be postponed from February to March.

This drill mainly focused on the new generation of lunar landing rocket "Space Launch System", including cryogenic liquid hydrogen filling and launch countdown process.During the process, the liquid hydrogen interface of the rocket's core stage leaked, and the team suspended operations multiple times to adjust the propellant flow, causing the countdown to be delayed.

Other problems were also encountered during the exercise: a pressure valve in the "Orion" crew module needed to be retightened after a recent replacement, which took a long time; the low temperature environment affected some cameras and equipment; and the ground team's audio communication experienced intermittent interruptions.

With 5 minutes and 15 seconds left in the countdown, the system automatically stopped the countdown due to a sudden increase in liquid hydrogen leakage rate.

NASA stated that this comprehensive exercise aims to detect and solve potential problems in advance to ensure a smooth actual launch. The relevant teams will conduct a comprehensive evaluation of the test data, resolve the technical conditions that emerged during the exercise one by one, and arrange a new round of comprehensive testing before determining the final launch date.

Nelson pointed out that it has been more than three years since the last launch of the "Space Launch System", and it is expected to encounter challenges. This is also the significance of conducting comprehensive exercises. Based on the results of the exercise, the team decided to abandon the February launch window and adjust the target to March.

The United States announced the "Artemis" return to the moon plan in 2019 and completed the "Artemis 1" unmanned lunar flight test in November 2022.

According to the plan, in the "Artemis 2" mission, four astronauts will fly around the moon aboard the "Orion" spacecraft for about 10 days. These astronauts did not participate in this exercise.

After the completion of the "Artemis 2" mission, NASA plans to continue promoting the "Artemis 3" manned lunar landing mission.