Tomorrow, NASA has a ‘dress rehearsal’ ahead of the flight around the moon

During the test, teams on the launch pad fill the SLS rocket with liquid oxygen and liquid hydrogen, then go through a step-by-step countdown procedure. Filling with hydrogen is the most sensitive part because the fuel is extremely cold, and even the slightest leak can stop the entire process. NASA wants to see if it can do the full procedure without interruption this time.

This is a new attempt after the first test earlier in February stalled due to problems in the hydrogen system, including a leak. Engineers then worked on repairs, replacement of parts and checks of equipment on the ramp, so that the same scenario would not happen again. This is why this test is important, because it gives an answer to the question of whether the problem has really been solved or if more interventions will be needed.

In the rehearsal itself, there will be no astronauts in the capsule, but the teams will monitor all parameters and communication as if the mission was really preparing for takeoff. If the test goes well, it is a strong signal that it is possible to move towards final preparations and an agreement about the launch date. If there are more delays again, it is realistic that the schedule will be pushed further.

Artemis II is planned as a four-crew, non-landing flyby of the Moon, and should be the first human flight outside of low Earth orbit since 1972. NASA is being cautious about communicating timelines, and has refused to lock in a date until after this key test. Therefore, a lot will be known only after Thursday and the analysis of the data from the test.