NASA teams at Kennedy Space Center are entering a decisive phase of preparations for the Artemis II mission, as engineers ready the Space Launch System (SLS) rocket and Orion spacecraft for a crucial prelaunch fueling test expected later this week.

Officials say work on the rocket, spacecraft, and launch infrastructure remains on schedule or ahead of expectations as the agency moves toward conducting a wet dress rehearsal, a full scale simulation of launch day operations that includes fueling the rocket and running through countdown procedures.

What the Wet Dress Rehearsal Will Test

The wet dress rehearsal is designed to validate the launch team’s ability to safely load more than 700,000 gallons of super cold propellants into the SLS rocket, perform a complete launch countdown, and then drain the fuel without astronauts aboard.

During the test, teams will rehearse key moments of the final countdown sequence, including multiple planned holds, resumes, and recycling of the clock in the final ten minutes before liftoff. The simulation is expected to conclude with a mock launch late Saturday night, though operations could extend into early Sunday if additional testing is required.

Engineers will also test the transition to the rocket’s automatic launch sequencer, which takes control during the final seconds before launch, ensuring systems perform as expected under realistic conditions.

Rocket and Spacecraft Systems Nearing Flight Readiness

Over the past several days, technicians completed servicing of the SLS solid rocket boosters, including fueling operations involving hydrazine in the booster aft skirts. Additional work inside the Orion spacecraft has focused on stowing flight hardware, conducting pyrotechnic preparations for the launch abort system, and verifying propulsion components.

NASA confirmed that engineers have completed checkouts of the rocket’s four RS 25 engines and pressurized key tanks in Orion’s propulsion system used during fueling. Teams are also continuing environmental control checks to protect sensitive spacecraft systems as colder than normal temperatures move across Florida.

Addressing Issues Ahead of Crewed Mission

As part of final readiness assessments, NASA engineers have addressed several technical issues identified during earlier testing. Adjustments were made to the emergency egress system at the launch pad after evacuation baskets stopped short during a recent evaluation. The braking system has since been modified to ensure full descent during an emergency.

NASA is also conducting additional sampling of Orion’s potable water system after initial tests showed higher than expected organic carbon levels. Officials say further analysis will confirm water quality standards are met before astronauts board the spacecraft.

Crew Status and Next Steps

The Artemis II crew entered quarantine in Houston on January 23, a standard precaution ahead of spaceflight to protect astronauts from illness as launch preparations intensify.

Following the wet dress rehearsal, NASA will assess test results before deciding whether the rocket and spacecraft can remain at the launch pad or require a rollback to the Vehicle Assembly Building for further work.

If all objectives are met, the test will mark a major milestone toward Artemis II, which aims to send astronauts on a historic journey around the Moon, laying the groundwork for future lunar landings and long term human exploration.

The fueling test is one of the final milestones before the mission’s launch, as NASA prepares for the first crewed flight around the Moon in decades.

NASA prepares for the first crewed flight around the Moon