The Space Launch System (SLS) has just one more hurdle to clear before this summer’s historic launch. This is known as the Wet Dress Rehearsal, where the fully-stacked SLS and Orion spacecraft will conduct a series of operations at the NASA Kennedy Space Center in Florida. This test follows the arrival of the SLS to Launch Complex 39B after making its big rollout on March 17th from the Vehicle Assembly Building (VLB).
The Wet Dress Rehearsal will run from Friday, April 1st, through Sunday, April 3rd, and will see the Artemis I launch team load propellant into the rocket’s tanks, conduct a full launch countdown, demonstrate the ability to recycle the countdown clock, and also drain propellants to give them an opportunity to practice the timelines and procedures they will use for launch. The weekend-long event will be live-streamed via the Kennedy Newsroom YouTube channel.
During the test, engineers will demonstrate the ability to conduct a full launch countdown at the pad. This will include loading over 700,000 gallons (~2.65 million liters) of cryogenic propellant into the SLS rocket and drain “ng it (“ka. “tanking”). Things kicked off this morning at around 03:00 AM EDT (12:00 PM PDT on Friday) when the Artemis I launch control team powered up the SLS’s core stage and began the countdown.
Throughout the day, they will be charging the Orion spacecraft’s flight batteries, conducting final preparations on the umbilical arms, and running a final pre-launch walkdown. Tanking operations will take place on Sunday, depending on the local weather conditions. This is crucial since weather constraints stipulate that there must be less than a 20% chance of lighting within 9.25 km (5 nautical miles) of the pad during the first hour, winds must not be above 69.45 km/h (37.5 knots), and the temperature cannot be below 5 °C (41 °F).
According to NASA Blogs, meteorologists with the U.S. Space Force Space Launch Delta 45 unit indicated that there is currently less than a 5% chance of lightning and are predicting a 10% chance of winds greater than 42.5 km/h (23 knots) tomorrow. NASA will provide live video of the rocket on the launchpad for the duration of the test and will host a post-media teleconference with key NASA and Artemis mission personnel on April 4th at 11:00 AM EDT (08:00 PDT).
With this test complete, NASA will be ready for the launch of the uncrewed Artemis I mission, which is scheduled to take place sometime in June. This will be followed by the first crewed flight of the SLS and Orion spacecraft (Artemis II) in May of 2024, which will consist of a four-person crew conducting a circumlunar flight. By 2025, NASA will conduct the long-awaited return to the Moon with Artemis III, consisting of a four-person crew and a two-person lunar landing.
Tune in to the Kennedy Newsroom YouTube channel to watch this last, crucial step before launch!
Update: You can catch the replay of the Artemis I Post-Wet Dress Rehearsal press briefing too.
Further Reading: NASA