Author: Madison Tuttle

While loading liquid hydrogen (LH2) on the rocket’s core stage earlier this afternoon, engineers detected a leak on the tail service mast , which is located at the base of the mobile launcher and connects to the core stage.

Though engineers stopped loading LH2 and liquid oxygen (LOX) on the core stage, the launch director gave approval for teams to chill down the ICPS LH2 lines to collect additional data and have completed that activity. Engineers will not load LH2 or LOX into the ICPS tanks, due to an issue with a helium check valve experienced several days ago. When teams paused propellant loading earlier today, there was about 49% of LOX on the core stage and about 5% of LH2 was loaded into the core stage tank prior to the hydrogen leak.

The terminal countdown will also not occur today due to the modified configurations and delays with propellant loading. Teams are reassessing the next steps and will determine a go-forward plan following today’s test.

Following the completion of slow fill for liquid hydrogen (LH2), teams encountered an issue when they started fast fill operations for LH2. After fast fill on LH2 began, a surge in pressure automatically stopped the flow of liquid hydrogen. Teams are working to troubleshoot this issue and the rocket is in a safe configuration. In the meantime, liquid oxygen flow was paused on the core stage to ensure the tanking operations for LOX and LH2 remain synchronized.

After fast fill resumes for liquid hydrogen to the core stage, teams will load minimal cryogenic propellants on the interim cryogenic propulsion stage. Because of an issue with a helium check valve found several days ago, teams will chill down the lines used to load propellant into the upper stage but not flow any actual propellant to the stage.

The clock is continuing to count down for now, and the team will work to re-synchronize the operations timeline and clock during a planned T-10-minute hold at which point the launch team will establish a new T-0.

Follow along with the countdown on the Exploration Ground Systems Twitter and watch a live stream of the test on the Kennedy Newsroom YouTube channel.

The mission management team for Artemis I met this morning to review the status of operations and continues to press ahead toward terminal countdown for the wet dress rehearsal test. Meteorologists with the U.S. Space Force Space Launch Delta 45 currently predict favorable weather conditions for tanking on April 14. There is currently a 5% chance of lightning within five nautical miles of the launch pad when tanking begins. Weather constraints stipulate there must be less than a 20% chance lightning within 5 nautical miles of pad during the first hour of tanking. Winds must not be above 37.5 knots and the temperature cannot be below 41 degrees Fahrenheit. 

Later today teams will perform a pre-launch walkdown of the rocket and ensure the Space Launch System’s core stage is prepared for the upcoming loading operations. 

NASA will provide live updates on the Exploration Ground Systems Twitter account. NASA is also streaming live video of the rocket and spacecraft at Launch Pad 39B on the Kennedy Newsroom YouTube channel. 

Overnight, launch controllers powered up the Orion spacecraft and the Space Launch System rocket’s core stage. Communications links between Orion and the Mission Control Center at Johnson Space Center in Houston were verified, and preparations of the four RS-25 engines, which will not be lit during the wet dress rehearsal, continued. Over the next several hours, controllers will charge Orion’s batteries and conduct final preparations and closeout activities for the umbilicals.

The umbilicals provide power, communications, coolant, and fuel to different parts of the rocket. Additional accessories provide access and stabilize the rocket and spacecraft. During launch, each umbilical releases from its connection point, allowing the rocket and spacecraft to lift off safely from the launch pad.

The mission management team is scheduled to meet at 11 a.m. EDT to review the status of operations. The next update will be posted after the conclusion of the meeting.

NASA will provide live updates on the Exploration Ground Systems Twitter account. NASA is also streaming live video of the rocket and spacecraft at Launch Pad 39B on the Kennedy Newsroom YouTube channel.

NASA is targeting Monday, April 4, to resume the Artemis I wet dress rehearsal test. The test was stopped Sunday, April 3 prior to tanking due to loss of ability to pressurize the mobile launcher using two fans. The fans are needed to provide positive pressure to the enclosed areas within the mobile launcher and keep out hazardous gases. Without this capability, technicians were unable to safely proceed with remotely loading the propellants into the rocket’s core stage and interim cryogenic propulsion stage.

The launch control team will meet at 6 a.m. EDT and review the status of the operations before deciding if they will proceed with propellant loading. The targeted test T-0 is planned for 2:40 p.m. EDT. Meteorologists with the U.S. Space Force Space Launch Delta 45 currently predict favorable weather conditions for tanking operations.

During a teleconference this evening, Mike Sarafin, Artemis I mission manager and Charlie Blackwell-Thompson, Artemis launch director indicated that teams are continuing to troubleshoot the issue with the fans and aim to have a resolution later tonight. NASA will provide an update the morning of April 4, prior to the tanking meeting.

The Space Launch System (SLS) core stage, interim cryogenic propulsion stage, and Orion spacecraft will remain powered up overnight. The SLS boosters will be powered down, and then powered up again Sunday morning. Teams will work through the night and into the morning to complete necessary preparations ahead of loading propellants into the rocket.

NASA is streaming live video of the rocket and spacecraft at the launch pad on the Kennedy Newsroom YouTube channel.

Teams have decided to scrub tanking operations for the wet dress rehearsal due to loss of ability to pressurize the mobile launcher. The fans are needed to provide positive pressure to the enclosed areas within the mobile launcher and keep out hazardous gases. Technicians are unable to safely proceed with loading the propellants into the rocket’s core stage and interim cryogenic propulsion stage without this capability.

Teams will now meet to determine next steps and establish a go forward plan. The next opportunity to proceed into tanking is Monday, April 4. Teams will discuss range and commodity availability as part of the forward plan.

At approximately 6:45 a.m. EDT, the launch director and mission management team chair gave the “go” to begin tanking the rocket. Meteorologists with Space Launch Delta 45 said there were no weather violations for the test. All elements are powered up and teams have moved the side flame deflectors into position and completed final preparations and closeouts of the umbilicals that connect the mobile launcher to the Space Launch System rocket and Orion spacecraft.

The flame deflectors divert ignited propellant away from the rocket and ground infrastructure at liftoff. Although the engines will not be lit during the test, launch controllers are using the wet dress rehearsal to practice countdown milestones like they would on launch day.

The umbilicals provide power, communications, coolant, and fuel to different parts of the rocket. Additional accessories provide access and stabilize the rocket and spacecraft. During launch, each umbilical releases from its connection point, allowing the rocket and spacecraft to lift off safely from the launch pad.

Cryogenic loading operations are schedule to begin around 7:20 a.m., or with L-7 hours, 20 minutes remaining in the countdown.

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.

The Artemis I launch team continues to press ahead through the wet dress rehearsal countdown. During the overnight hours after determining four lightning strikes at Launch Pad 39B would not stop the countdown from continuing,  the interim cryogenic propulsion stage (ICPS) and solid rocket boosters of the Space Launch System rocket were powered up. Shortly after, all non-essential personnel left the launch pad.

Teams continue to prepare to load super-cooled liquid hydrogen and liquid oxygen into the Space Launch System core stage as part of the Artemis I test, which began on April 1.

At 6 a.m. EDT, or L-8 hours, 40 minutes, the launch team reached a planned 1 hour, 30-minute built-in hold in the countdown. During this time the mission management team will make a “go” or “no-go” decision to proceed with tanking operations. If mission mangers elect to proceed with cryogenic loading operations, it is scheduled to begin at L-7 hours 40 minutes.

Tanking milestones include filling the rocket’s core stage and ICPS tanks with over 700,000 gallons of liquid oxygen and liquid hydrogen. This will occur over a series of different propellant loading milestones to fill, top off, and replenish the tanks.

NASA is streaming live video of the rocket and spacecraft at the launch pad on the Kennedy Newsroom YouTube channel. NASA is also sharing live updates on the Exploration Ground Systems Twitter account.

The next blog update will be provided after the “go” or “no-go” decision to proceed with tanking operations.

Engineers confirmed there were four lightning strikes to the lightning towers within the perimeter of Launch Pad 39B. Teams have determined the first three were low intensity strikes to tower two and are continuing to review data from the fourth strike, which was higher in intensity to tower one. At the time of the strikes, Orion and the Space Launch System (SLS) core stage were powered up and the solid rocket boosters and interim cryogenic propulsion stage (ICPS) were not. Teams currently see no constraints to proceeding with the test countdown timeline as planned and will continue procedures to power up the SLS boosters and ICPS overnight.

Overnight, engineers will also work to make up time for activities that were paused due to the severe weather. The Mission Management Team will review the schedule and data from the power ups and sensors at the pad at a 6 a.m. EDT tanking meeting before making the decision to proceed with the test.