NASA's Artemis II Wet Dress Rehearsal: Full-Fueling Test of SLS Rocket Underway
NASA teams are progressing through the countdown for the Artemis II wet dress rehearsal, a comprehensive fueling test of the Space Launch System (SLS) rocket at Kennedy Space Center in Florida. Throughout the night, engineers diligently monitored systems as temperatures dropped and winds remained elevated at the launch site.
Core Stage Activation and Propellant Loading
Early this morning, at approximately L-39 hours and 30 minutes, the rocket's core stage was successfully powered up. In the upcoming hours, it is anticipated to be loaded with more than 700,000 gallons of liquid oxygen and liquid hydrogen during the tanking phase. This process unfolds gradually, with the tanks being filled, topped off, and replenished as necessary.
The interim cryogenic propulsion stage was powered overnight, while the Orion spacecraft has remained powered for several days due to colder-than-usual conditions in Florida. Engineers are now preparing to charge Orion's flight batteries and are set to begin charging the core stage batteries as well.
Countdown Timeline and Simulated Launch Window
The countdown clock commenced at 8:13 p.m. Eastern Standard Time, corresponding to 6:43 a.m. Indian Standard Time. This marked L-48 hours and 40 minutes ahead of a simulated launch window scheduled to open at 9 p.m. EST on Monday, February 2, or 7:30 a.m. IST on Tuesday, February 3. The rehearsal is expected to continue until about 1 a.m. EST on February 3, which translates to 11:30 a.m. IST.
NASA's countdown follows a structured approach built around both "L minus" and "T minus" times. L-minus tracks the time remaining until liftoff, while T-minus tracks the sequence of events leading up to launch. Teams can pause the clock to manage tasks or align with a target window. During these holds, the T-minus clock stops, while L-minus continues to run.
Simulated Launch Conditions and Crew Milestones
As part of the rehearsal, teams will pause briefly at T-1 minute and 30 seconds, resume the count, then stop again at T-33 seconds. The clock will then be recycled back to T-10 minutes for a second terminal countdown, ending once more at T-33 seconds. This sequence is designed to mirror real launch conditions, including scenarios where a launch might be delayed or scrubbed.
Although the Artemis II crew is not participating in the wet dress rehearsal itself, crew-related milestones are integrated into the timeline. The Artemis closeout crew will practice launch-day procedures, such as sealing the Orion crew module and closing the launch abort system hatches, as preparations advance toward NASA's first crewed Artemis mission around the Moon.
Live Coverage and Data Review
A live video stream of the rocket at the pad has been running continuously on NASA's YouTube channel, with NASA planning a separate feed during the fueling operations. Real-time blog updates are also anticipated throughout the test. All information released so far is sourced directly from NASA's official Artemis II status updates.
Once the test concludes, propellants will be drained from the rocket, and engineers will meticulously review the data before setting a formal launch target. This rehearsal is a pivotal step in ensuring the success of future Artemis missions, paving the way for human exploration beyond Earth's orbit.
