NASA Delays SLS Wet Dress Rehearsal a Second Time

The Artemis I team is stopping to take every precaution for the rocket’s final major test.

NASA once again halted its Artemis I Space Launch System (SLS) wet dress rehearsal Monday evening—the second time this week.

Previously, the rocket encountered a temperature limit issue that paused the countdown for several hours on Sunday. The rocket’s propellant, liquid oxygen, is an extremely cold liquid that must be maintained at minus 297 degrees Fahrenheit.

After resolving the temperature issue, the team encountered another issue Monday—this time involving a panel that controls the core stage vent valve. The team managed to fill the tank up to 50 percent capacity, but the valve issue prevented them from relieving pressure from the core stage during fueling.

“I’m confident we’re going to get through the wet dress in fairly short order,” Artemis mission manager Mike Sarafin told reporters during a teleconference Sunday. “We’ve just got to work through these problems.”

Since the teams were nearing the end of their shifts, the launch director called off the test for the remainder of the day.

During a teleconference late Tuesday afternoon to provide additional updates to Artemis I’s final major test, which originally started Friday and was expected to last two days, Artemis Launch Director Charlie Blackwell-Thompson said, “We got teams out to the pad today and after inspection we found that the manual hand valve was in the closed position and should have been opened.” 

“There’s a significant amount of test objectives that were completed,” he added.

Artemis I, the first of several trips back to the moon, will be uncrewed—circling the moon and splashing back down in the Pacific Ocean. Crewed missions will begin in phase two of the program, and will eventually land the first woman and person of color on the lunar surface as soon as 2026.

Following the completion of the rehearsal, the SLS will be drained of all fuel and rolled back into the Vehicle Assembly Building (VAB) for additional preparations for launch.

Despite the week’s challenges, Blackwell remained hopeful Tuesday.

“This is an incredible vehicle,” he said. “An incredible capability that is going to return us to the moon, and one day, take us onto Mars. … Would we have loved to finish the test yesterday? You bet. But I think that we do our best work, I think NASA does some of its best work when it is solving problems.”

“We’re not ready to give up on it yet,” added Mike Sarafin, Artemis mission manager.

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