NASA’s Artemis I Moon Rocket to Depart Launch Pad 39B Today

Crawler-transporter 2 (CT-2) makes its way along the crawlerway to Launch Complex 39B at NASA’s Kennedy Space Center in Florida. In view atop the mobile launcher on the pad are the Artemis I Space Launch System (SLS) and Orion spacecraft. Credit: NASA/Ben Smegelsky

At approximately 5:30 p.m. ET today, NASA’s Artemis I Moon rocket atop the crawler-transporter is scheduled to leave launch pad 39B and begin its 4-mile trek to the Vehicle Assembly Building (VAB) at NASA’s Kennedy Space Center in Florida. 

Once inside the VAB, teams will work on replacing a faulty upper stage check valve and a small leak within the tail service mast umbilical ground plate housing on the mobile launcher while the supplier for the gaseous nitrogen makes upgrades to their pipeline configuration to support Artemis I testing and launch. Following completion, teams will return to the launch pad to complete the next wet dress rehearsal attempt. 

The NASA Kennedy Twitter account will release an update once the roll has begun. Watch a live stream of the rocket departing the pad and arriving at VAB on the Kennedy Newsroom YouTube channel and check back here for updates.

NASA’s Artemis I Rocket Readying for Return to Vehicle Assembly Building

Wildflowers frame a view of the Artemis I Space Launch System (SLS) and Orion spacecraft on Launch Pad 39B
Wildflowers frame a view of the Artemis I Space Launch System (SLS) and Orion spacecraft on Launch Pad 39B at NASA’s Kennedy Space Center in Florida. Credit: NASA/Ben Smegelsky

Teams at NASA’s Kennedy Space Center in Florida are preparing the Space Launch System (SLS) rocket and Orion spacecraft for their return to the Vehicle Assembly Building (VAB) early next week. As work continues at the launch pad throughout the weekend, we will also continue working closely with our commercial crew partners to confirm a date and time. The transition is underway to move from the testing configuration to the roll back formation needed to return to the VAB. This process includes offloading hydrazine from the twin solid rocket boosters and disconnecting the rocket and spacecraft from the ground systems infrastructure at the launch pad. The core stage propellant was drained shortly after completing the last test attempt. The rocket and spacecraft remain in a safe configuration and will soon be placed atop the crawler-transporter for the 4-mile trek to the VAB.

Inside the VAB, engineers will repair a faulty helium check valve and a hydrogen leak on the mobile launcher while the supplier for the gaseous nitrogen makes upgrades to their pipeline configuration to support Artemis I testing and launch.

While most objectives associated with the wet dress rehearsal were met during recent testing, teams plan to return to the launch pad when repairs and checkouts in the VAB are complete for the next full wet dress test attempt. Following completion of the test, SLS and Orion will return to the VAB for the remaining checkouts before rolling back out to the pad for launch.

Watch a live stream of the rocket on the Kennedy Newsroom YouTube channel and check back here for updates.

Artemis I WDR Update: Third Test Attempt Concluded

Teams concluded today’s wet dress rehearsal test at approximately 5:10 p.m. EDT after observing a liquid hydrogen (LH2) leak on the tail service mast umbilical, which is located at the base of the mobile launcher and connects to the rocket’s core stage. The leak was discovered during liquid hydrogen loading operations and prevented the team from completing the test.

Before ending the test, teams also met test objectives for the interim cryogenic propulsion stage by chilling down the lines used to load propellant into the upper stage. They did not flow any propellant to the stage because of an issue with a helium check valve identified several days ago.

When teams paused propellant loading, the rocket’s core stage liquid oxygen tank was about 49% filled and the liquid hydrogen tank had been loaded to about 5% capacity prior to the hydrogen leak.

Teams are now working to drain propellant from the rocket. They will inspect the umbilical connection, review data, and establish a go-forward plan to address the hydrogen leak.

NASA plans to host a media teleconference April 15 to provide updates on troubleshooting and next steps for the wet dress rehearsal test.

Artemis I WDR Update: Teams Complete Modified Upper Stage Liquid Hydrogen Operations

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.

Artemis I WDR Update: Teams Working Solution to Continue Propellant Loading Operations

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.

Artemis I Update: Weather Still Favorable for Artemis I Wet Dress Rehearsal

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. 

Artemis I Update: Preparations Continue, Rocket’s Core Stage Powered Up

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.

Artemis I Wet Dress Rehearsal Testing Continues

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.

Artemis I Wet Dress Rehearsal Scrub

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.

Artemis I WDR Update: Go for Proceed for Tanking

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.