NASA will again rehearse Artemis II moon launch after rocket repairs

The wet dress rehearsal officially began Wednesday evening and continued Thursday morning, as teams powered up parts of the rocket and spacecraft and charged the flight batteries. However, the main part of the test will begin once mission leaders give the green light to fuel the Space Launch System rocket.

The booster will then be filled with more than 700,000 gallons of cryogenic propellant, and mission leaders will practice counting down to a simulated launch time of 8:30 p.m. ET.

As part of the test, NASA plans to conduct two walkthroughs of the final 10 minutes of the countdown, with a break at T minus 1 minute and 30 seconds. At T-minus 33 seconds, NASA plans to reset the clock to T-minus 10 minutes and start again.

These stops and starts are designed to demonstrate that the rocket’s systems are operating as designed during the final part of the countdown, when automated systems take control of the booster. Pauses and resets also give mission leaders the opportunity to practice different scenarios, such as situations in which problems arise that require investigation or in which a launch must be canceled due to technical problems or poor weather conditions.