posted 02-19-2026 11:36 AM               

Upper stage propellant loading begins

As teams continue to fuel the SLS rocket's core stage with liquid oxygen and liquid hydrogen, teams began loading liquid hydrogen into the rocket's interim cryogenic propulsion stage or upper stage.

posted 02-19-2026 12:14 PM               

SLS core stage hydrogen in replenish mode; thus far no leaks reported

NASA teams have transitioned the SLS rocket's core stage liquid hydrogen tank to replenish mode. This marks an important milestone in the test, as teams reached this step without exceeding the ground safety limit of the hydrogen leak concentration, as was observed during the first Artemis II wet dress rehearsal.

After completing fast fill and topping, replenish keeps the tank at flight-ready levels by replacing any LH2 lost to boil-off. Replenish is essential for maintaining stable pressure and temperature in the tank as the countdown continues. Cryogenic propellants like liquid hydrogen naturally warm and evaporate over time, even in insulated tanks. Replenishing the tanks counteracts this by continuously adding small amounts of liquid propellant to maintain the correct volume and pressure.

This phase ensures the core stage remains fully fueled and ready to power its four RS-25 engines at liftoff, providing the thrust needed to send Orion and its crew on their journey around the Moon.

posted 02-19-2026 01:50 PM               

All SLS cryogenic tanks in replenish mode

NASA teams have transitioned all cryogenic tanks on the SLS (Space Launch System) rocket to replenish mode. This includes both liquid hydrogen and liquid oxygen tanks for the core stage and the interim cryogenic propulsion stage.

Cryogenic propellants naturally warm and evaporate over time, even in insulated tanks. Replenish counteracts this by continuously adding small amounts of liquid hydrogen and liquid oxygen to maintain proper levels and pressure. This ensures the rocket remains fully fueled and stable as the countdown progresses toward terminal count.

Following all stages replenish, teams will perform final system checks and verify valve and sensor performance before transitioning to the terminal countdown sequence, which includes simulated launch operations and final readiness verifications.

With all stages in replenish, the Artemis II wet dress rehearsal is now in its final fueling configuration, bringing this test wet dress rehearsal operations closer to terminal count.

posted 02-19-2026 03:02 PM               

Closeout crew en route to White Room

NASA's Artemis II closeout crew is en route to the White Room inside the crew access arm at Launch Pad 39B. This specialized team is responsible for securing the Orion spacecraft and ensuring all access points are properly configured before simulated crew ingress operations.

The White Room is the environmentally controlled area at the end of the crew access arm, providing a clean and safe space for astronauts to enter Orion on launch day. During the wet dress rehearsal, the closeout crew will close the spacecraft's hatches, verify hatch seals, check environmental conditions, and confirm all systems are ready for the next steps in the countdown.

In addition, the pad rescue team will be positioned to respond immediately in the unlikely event of an emergency, ensuring safe evacuation procedures for pad personnel. Their presence ensures that all operations meet stringent safety standards as the SLS (Space Launch System) rocket and Orion spacecraft move closer to flight readiness. These teams are essential for mitigating risk and supporting the complex choreography of Artemis II's prelaunch activities.

posted 02-19-2026 03:50 PM               

Closeout crew closes Orion hatch

As part of the Artemis II wet dress rehearsal, NASA teams have closed the Orion crew module hatch inside the White Room at Launch Pad 39B. This step simulates launch day procedures, ensuring the spacecraft is sealed and ready for launch. The Artemis II astronauts are not participating in today's rehearsal, but the close out crew simulated strapping them into their seats.

The closeout crew inspects and cleans the hatch seals to maintain airtight integrity, verifies environmental controls inside the crew module, and confirms all mechanical and electrical connections are secure before closure.

Closing the hatch is a critical milestone that demonstrates Orion's readiness for flight and validates procedures for the first crewed Artemis mission around the Moon. The closeout crew will next close the launch abort system hatch.

posted 02-19-2026 05:40 PM               

Launch abort system hatch closed

NASA teams have closed the launch abort system hatch during the Artemis II wet dress rehearsal, simulating final launch day procedures. The launch abort system hatch provides access to the Orion crew module through the abort tower and must be securely sealed to ensure crew safety during ascent.

Closing the launch abort system hatch is a critical milestone that confirms the spacecraft is fully configured for flight. The hatch is designed to protect astronauts in the event of an emergency during launch, and proper hatch integrity ensures the system can perform as intended.

With the hatch secured, the closeout crew validates mechanical seals, verifies environmental conditions, perform leak checks, and confirms readiness for the next steps in the countdown sequence.

Next up, the closeout crew will depart the launch pad once its work is completed.

posted 02-19-2026 06:09 PM               

Closeout crew departs the launch pad

NASA’s Artemis II closeout crew has completed its critical tasks and departed NASA Kennedy's Launch Complex 39B during the Artemis II wet dress rehearsal.

The departure of the closeout crew marks the transition to the final countdown phase of the test, ensuring the launch pad is clear and safe for simulated liftoff procedures. Their work validates launch day protocols and confirms Orion and the SLS (Space Launch System) rocket are configured for flight readiness.

With the pad secured, teams will continue monitoring fueling operations and prepare for wet dress rehearsal terminal count: the final ten minutes of the countdown.

posted 02-19-2026 07:37 PM               

T-10 minutes and holding

The launch director has extended the T-10 minute hold to allow for time to complete final preparations for the terminal countdown of today's wet dress rehearsal, including bringing the core stage engine section temperature into the necessary range for launch. It is currently just shy of the temperature that would be required if SLS were planning to launch, but engineers expect it to rise shortly.

A new simulated T-0 time will be set once the temperature has risen into the correct range.

posted 02-19-2026 07:45 PM               

Entering terminal count

NASA teams have now officially entered the final ten minutes of today's Artemis II wet dress rehearsal countdown known as terminal count after Charlie Blackwell-Thompson, NASA's Artemis launch director, gave the "go" to proceed toward the simulated T-0 time of 8:42 p.m.

During terminal count, automated systems take control of countdown operations, final checks of flight computers, engine bleed systems, and ground support equipment occur, and the rocket transitions to internal power, and the countdown proceeds toward simulated engine start.

Terminal count is designed to confirm that all systems can perform flawlessly under launch conditions, ensuring readiness for Artemis II – the first crewed mission of the Artemis program.

During this first terminal count run, the team will pause at T-1 minute and 30 seconds for up to three minutes, then resume until T-33 seconds before launch and pause again. After that, they will recycle the clock back to T-10 minutes and conduct a second terminal countdown to approximately T-33 seconds before ending the sequence. This process simulates real-world conditions, including scenarios where a launch might be scrubbed due to technical or weather issues.

Update at 8:39 p.m. EST: The crew access arm has been retracted. The launch abort system would be available to pull the crew to safety in the event of an emergency on the launch pad beginning 5 minutes 25 seconds before launch.

posted 02-19-2026 07:50 PM               

First terminal count complete after glitch

The terminal countdown was paused due to a booster avionics system voltage anomaly, but resumed and continued to planned recycle point. The team is now resetting the countdown as planned.

posted 02-19-2026 09:32 PM               

Second terminal count conducted; wet dress rehearsal complete

NASA teams officially entered the second round of terminal countdown, or the final ten minutes of today's Artemis II wet dress rehearsal countdown after successfully recycling the clock back to T-10 minutes. The new T-0 was set for 10:17 p.m. EST.

The WDR ended at 10:16 p.m., concluding as planned at T-29 seconds in the countdown.

posted 02-20-2026 10:47 AM               

NASA Begins Artemis II Launch Pad Ops After Successful Fuel Test

NASA successfully fueled its SLS (Space Launch System) rocket and demonstrated the launch countdown for Artemis II on Thursday (Feb. 19) during a wet dress rehearsal at the agency's Kennedy Space Center in Florida.

Engineers loaded more than 700,000 gallons of liquid propellant into the rocket, sent a closeout crew to the launch pad to demonstrate closing the Orion spacecraft's hatches, and completed two runs of terminal count — the final phase of the launch countdown. The Artemis II crew also observed part of the test from the Launch Control Center at NASA Kennedy.

During the test, teams closely monitored liquid hydrogen fueling operations, which proved challenging during previous tests. Hydrogen gas concentrations remained under allowable limits, giving engineers confidence in new seals installed in an interface used to route fuel to the rocket.

Early in fueling operations, teams experienced a loss of ground communications in the Launch Control Center. Operators temporarily moved to backup communication methods to maintain safe propellant loading activities before normal communications channels were restored. Engineers isolated the equipment that caused the issue.

While engineers review data from the test, the Artemis II crew is preparing to enter quarantine late Friday, Feb. 20, in Houston. Although NASA has not set a formal launch date, beginning the roughly 14-day quarantine to limit the crew's exposure to illness before launch preserves flexibility in the March launch window.

Over the next several days, technicians will use cranes to set up temporary access platforms on the mobile launcher. The platforms will allow them to reach the upper left and right segments of the SLS solid rocket boosters and core stage intertank to service the flight termination system and retest it to meet Eastern Range safety requirements. The platforms were developed based on lessons learned during Artemis I and enable NASA to complete end-to-end testing of the safety system while at the launch pad rather than rolling back to the Vehicle Assembly Building at NASA Kennedy for retesting.

The closeout crew also will practice closeout operations once more, adding to the team's proficiency.

posted 02-21-2026 09:47 AM               

NASA Troubleshooting Artemis II Rocket Upper Stage Issue, Preparing to Roll Back

NASA is taking steps to potentially roll back the Artemis II rocket and Orion spacecraft to the Vehicle Assembly Building (VAB) at the agency’s Kennedy Space Center in Florida after overnight Feb. 21 observing interrupted flow of helium in the SLS (Space Launch System) rocket’s interim cryogenic propulsion stage. Helium flow is required for launch.

Teams are actively reviewing data, and taking steps to enable rollback positions for NASA to address the issue as soon as possible while engineers determine the best path forward.

In order to protect for troubleshooting options at both Pad B and the VAB, teams are making preparations to remove the pad access platforms installed yesterday, which have wind-driven constraints and cannot be removed during high winds, which are forecasted for tomorrow. This will almost assuredly impact the March launch window.

posted 02-22-2026 12:47 PM               

NASA to Rollback Artemis II Rocket, Spacecraft

Weather pending, NASA will roll the SLS (Space Launch System) rocket and Orion spacecraft for Artemis II off the launch pad at the agency’s Kennedy Space Center in Florida as soon as Tuesday, Feb. 24.

Engineers are continuing to prepare for the move after encountering an issue with the flow of helium to the rocket's upper stage.

On Feb. 21, managers decided to remove recently installed platforms before high winds descend on the Space Coast, which poised teams for rollback while discussions about the issue were ongoing. Returning to the Vehicle Assembly Building at Kennedy is required to determine the cause of the issue and fix it.

Teams are reviewing the exact time to begin the approximately 4 mile, multi-hour trek.

The quick work to begin preparations for rolling the rocket and spacecraft back to the VAB potentially preserves the April launch window, pending the outcome of data findings, repair efforts, and how the schedule comes to fruition in the coming days and weeks.

The Artemis II crew members were released from quarantine the evening of Feb. 21 and remain in Houston.

posted 02-22-2026 06:28 PM               

Artemis II moon mission delayed to April due to rollback for repairs

NASA's march to the moon has been delayed to April.

The space agency's plans to launch the Artemis II crew as soon as the first week of March have been postponed by at least a month due to their rocket needing to return to its assembly building. The decision to roll back the Space Launch System (SLS) came after a problem emerged with its upper stage.

posted 02-23-2026 08:20 PM               

NASA Targets Artemis II Rollback on Wednesday

Due to weather, NASA now is targeting early Wednesday, Feb. 25, to roll the SLS (Space Launch System) rocket and Orion spacecraft for Artemis II off the launch pad and back to the Vehicle Assembly Building (VAB) at the agency's Kennedy Space Center in Florida. Cold temperatures and high winds are expected Tuesday, and rolling on Feb. 25, gives teams enough time to complete preparations at the launch pad that were limited today by high winds in the area.

The approximately 4-mile trek is expected to take up to 12 hours. Once back in the VAB, teams will immediately begin work to install platforms to access the area of the helium flow issue.

posted 02-24-2026 04:27 PM               

First Motion Set for Artemis II Rollback

NASA is targeting approximately 9 a.m. EST, Wednesday, Feb. 25, to begin rolling the SLS (Space Launch System) rocket and Orion spacecraft for Artemis II off the launch pad and back to the Vehicle Assembly Building (VAB) at the agency's Kennedy Space Center in Florida. Teams will continue to monitor winds and temperatures in advance of the roll.

The approximately 4-mile trek is expected to take up to 12 hours. Once back in the VAB, teams will immediately begin work to install platforms to access the area of the helium flow issue. Teams also will take advantage of the time in the VAB to replace batteries in the flight termination system and retest it, and replace additional batteries in the upper stage.

posted 02-25-2026 09:24 AM               

SLS rolls back to assembly building

NASA's SLS (Space Launch System) rocket and Orion spacecraft for the Artemis II mission began rolling off the launch pad at 9:38 a.m. EST, Feb. 25, at NASA's Kennedy Space Center in Florida.

Rolling from Launch Pad 39B to the Vehicle Assembly Building at NASA Kennedy is expected to take up to 12 hours.

posted 02-26-2026 07:34 AM               

SLS rolled into VAB for repairs

The SLS (Space Launch System) rocket and Orion spacecraft for NASA's Artemis II mission arrived at the Vehicle Assembly Building from Launch Pad 39B at approximately 8 p.m. EST Feb. 25, at NASA's Kennedy Space Center in Florida.

While in the assembly building, technicians will troubleshoot the helium flow issue to the rocket's upper stage, replace batteries on the rocket's upper stage, core stage, and solid rocket boosters as well as service its flight termination system.

posted 02-27-2026 12:13 AM               

Repairs begin in Vehicle Assembly Building

Once NASA's Artemis II SLS (Space Launch System) rocket and Orion spacecraft arrived at the Vehicle Assembly Building (VAB) Feb. 25, technicians immediately began addressing why the flow of helium to the SLS upper stage was interrupted as engineers were reconfiguring the rocket following a successful wet dress rehearsal on Feb. 21.

To make the repairs, teams are installing two sets of internal access platforms inside the launch vehicle stage adapter and must remove thermal blankets that cover the area they are interested in – a point on the rocket's interim cryogenic propulsion system, or upper stage. The area provides connections for multiple umbilicals, including tubing used to fill the upper stage with helium. Helium is used to maintain proper environmental conditions, and to pressurize the stage for flight.

Above: The interim cryogenic propulsion stage has two umbilicals. The highest, smaller ICPS forward plate includes a liquid hydrogen vent and environmental control system air line. The lower, larger aft plate supplies liquid hydrogen, liquid oxygen, and includes a helium quick disconnect and hazardous gas sensing. (NASA)

Engineers have narrowed the issue preventing the helium flow to two potential components: a seal on the tubing's quick disconnect and a check valve on the other end of that tubing.

While the rocket and spacecraft are in the VAB, teams also will install new batteries for the SLS's upper stage, core stage, and solid rocket boosters, as well as retest its flight termination system and avionics and control systems.

Above: Shown is a mated flight and ground plate for the SLS (Space Launch System) core stage's liquid hydrogen tail service mast umbilical. The quick disconnect device sits between these interface plates once the umbilicals are connected and provide access for flowing propellant into the core stage's fuel tank. The tail service mast umbilical connects from the zero-level deck on the mobile launcher to the SLS (Space Launch System) rocket core stage aft section and provide liquid oxygen and liquid hydrogen fluid lines and electrical cable connections to the SLS core stage engine section to support propellant handling during prelaunch operations. (NASA)

The Orion spacecraft's launch abort system batteries will be recharged, and engineers may refresh some of the stowed items inside the crew module.

Engineers have optimized planned work in the VAB, and much of the work to come can be done in parallel. Pending the outcome of data reviews, repair efforts, and how the schedule comes to fruition in the coming days and weeks, the Artemis II Moon rocket will roll back to Launch Pad 39B in time for April launch opportunities.

posted 03-03-2026 02:20 PM               

NASA Repairs Upper Stage Helium Flow, Preps Continue Ahead of Rollout

With NASA's Artemis II SLS (Space Launch System) rocket and Orion spacecraft in the Vehicle Assembly Building at the agency's Kennedy Space Center in Florida, technicians have accessed the launch vehicle stage adapter to inspect components that prevented helium from flowing to the upper stage after a Feb. 21 wet dress rehearsal.

Engineers determined a seal in the quick disconnect, through which helium flows from the ground systems to the rocket, was obstructing the pathway. The team removed the quick disconnect, reassembled the system, and began validating the repairs to the upper stage by running a reduced flow rate of helium through the mechanism to ensure the issue was resolved. Engineers are assessing what allowed the seal to become dislodged to prevent the issue from recurring.

While the upper stage repair has been underway, technicians also have been working to refresh other systems on the rocket. They are activating a new set of flight termination system batteries ahead of end-to-end retesting of the system and also are replacing the flight batteries on the upper stage, core stage, and solid rocket boosters, and charging the Orion launch abort system batteries.

Work to replace a seal on the core stage liquid oxygen line feed system began March 2. Once complete, teams will reassemble the oxygen tail service mast umbilical plate and perform various integrity tests to ensure the seal interface is tight.

Work on the rocket and spacecraft will continue in the coming weeks as NASA prepares for rolling the rocket out to the launch pad again later this month ahead of a potential launch in April.