With the Axiom-1 astronauts now safely aboard the International Space Station, NASA teams at Kennedy Space Center continue efforts to complete the last big test of the rocket destined for the Artemis I mission.

Crews are hoping to complete the simulated countdown and fueling procedures collectively known as the wet dress rehearsal. 

The test originally began on April 1, with the call to stations, and teams tried to work through to tanking (loading the liquid oxygen and liquid hydrogen) on, April 3. However, a pressure issued forced crews to scrub the simulated launch Sunday.

Crews were able to get closer to launch on April 4, and loaded about 50% of the liquid oxygen into the core stage tank after troubleshooting a temperature limit issue for several hours. Crews were later unable to start loading the liquid hydrogen due to “an issue with a panel on the mobile launcher that controls the core stage vent valve,” according to a KSC spokesperson. 

“Sometimes you run into something that's a little different than what you were expecting," said NASA spokesman Tom Whitmeyer during a teleconference following the end of testing on April 4.  "It's kind of like putting a puzzle together and you start to put the pieces in, and it's not looking the way that you thought it should look."

NASA said they were able to complete a number of checks during the first two attempts to complete tanking, which included the following: 

• Configuring Launch Pad 39B and the mobile launcher for the test, just as it will have to be prepared for launch
  
  
• Clearing personnel and equipment from the launch pad after configuration in order to proceed with propellant loading
  
  
• Powering up Orion and the SLS rocket systems in launch configuration, including the solid rocket boosters, the core stage and the interim cryogenic propulsion stage
  
  
• Checking out and verifying the Orion spacecraft countdown and commanding by flight controllers at NASA Johnson Space Flight in Houston
  
  
• Checking out the guidance, navigation and control system, and all the integrated software that operates across the rocket, Orion, ground systems and ground support centers including the Launch Control Center
  
  
• Verifying and checking out all the range safety and systems with the range
  
  
• Draining the liquid oxygen and liquid hydrogen after the test
  
  
• Powering down the rocket, the spacecraft and ground systems and putting them in a safe configuration

However, without going through the full process, officials said they wanted to try one more time. In order to not interfere more with the launch schedule of missions heading to the International Space Station, the Exploration Ground Systems team (those primarily running wet dress) decided to stand down until after the Axiom 1 mission launched on April 8. 

However, as they were gearing up to start again Saturday, they found another issue, this time with interim cryogenic propulsion stage (ICPS). 

Because of this, NASA pushed the wet dress rehearsal to Tuesday, with tanking on Thursday. Following the test, crews expect to roll the rocket back to the Vehicle Assembly Building to further assess the ICPS issue.

The conclusion of the test will also allow teams to get a better idea of when the rocket will be able to launch for the Artemis I mission to the moon.