NASA Artemis I Wet Dress Rehearsal Countdown Resumes

NASA’s Space Launch System (SLS) rocket with the Orion spacecraft aboard is seen atop a mobile launcher at Launch Complex 39B, Sunday, April 3, 2022, as the Artemis I launch team conducts the wet dress rehearsal test at NASA’s Kennedy Space Center in Florida. Ahead of NASA’s Artemis I flight test, the wet dress rehearsal will run the Artemis I launch team through operations to load propellant, conduct a full launch countdown, demonstrate the ability to recycle the countdown clock, and drain the tanks to practice timelines and procedures for launch. Credit: NASA/Joel Kowsky

The countdown for the wet dress rehearsal has resumed at 10:52 a.m. EDT and clocks have picked back up at T-6 hours, 40 minutes on the clock (L-7 hours, 10 minutes). A new planned T-0 of 6:02 p.m. has been established.

An earlier issue with an outage with the vendor of gaseous nitrogen required for tanking preparations has been resolved. Overnight, teams also resolved the issue with the malfunction of the fans used to provide positive pressure to enclosed areas in the mobile launcher and keep out hazardous gases, and they have a plan for operating the fans to prevent issues from reoccurring. The team was able to successfully bring up and run the primary fan through the night to provide confidence, and has configured the secondary fan to run at 80% capacity to support tanking operations.

At approximately 10 a.m. EDT, the launch director gave the “go” to begin tanking the rocket. Cryogenic loading operations are scheduled to begin with chilling down the liquid oxygen lines for the core stage. Once propellant loading operations begin, liquid oxygen (LOX) and liquid hydrogen (LH2) will flow into the into the rocket’s core stage and interim cryogenic propulsion stage tanks and be topped off and replenished as some of cryogenic propellant boils off. The team will also conduct leak checks to ensure propellant loading is proceeding as expected.

NASA is streaming live video of the rocket and spacecraft at the launch pad on the Kennedy Newsroom YouTube channel. Venting may be visible during tanking operations. NASA is also sharing live updates on the Exploration Ground Systems Twitter account.

The next blog update will be provided when core stage propellant loading is underway.