
Engineers are making progress repairing the area where a liquid hydrogen leak was detected during the Artemis I launch attempt Sept. 3, and NASA is preserving options for the next launch opportunity as early as Friday, Sept. 23.
Technicians constructed a tent-like enclosure around the work area to protect the hardware and teams from weather and other environmental conditions at Launch Pad 39B. They have disconnected the ground- and rocket-side plates on the interface, called a quick disconnect, for the liquid hydrogen fuel feed line, performed initial inspections, and began replacing two seals – one surrounding the 8-inch line used to fill and drain liquid hydrogen from the core stage, and another surrounding the 4-inch bleed line used to redirect some of the propellant during tanking operations. The SLS rocket and Orion spacecraft are in good condition while remaining at the launch pad.
Once the work is complete, engineers will reconnect the plates and perform initial tests to evaluate the new seals. Teams will check the new seals under cryogenic, or supercold, conditions no earlier than Sept. 17 in which the rocket’s core stage and interim cryogenic propulsion stage will be loaded with liquid oxygen and liquid hydrogen to validate the repair under the conditions it would experience on launch day. Engineers are in the process of developing a full plan for the checkouts.
NASA has submitted a request to the Eastern Range for an extension of the current testing requirement for the flight termination system. NASA is respecting the range’s processes for review of the request, and the agency continues to provide detailed information to support a range decision.
In the meantime, NASA is instructing the Artemis team to move forward with all preparations required for testing, followed by launch, including preparations to ensure adequate supplies of propellants and gases used in tanking operations, as well as flight operations planning for the mission. NASA has requested the following launch opportunities:
- Sept 23: Two-hour launch window opens at 6:47 a.m. EDT; landing on Oct. 18
- Sept. 27: 70-minute launch window opens at 11:37 a.m.; landing on Nov. 5
NASA’s teams internally are preparing to support additional dates in the event flexibility is required. The agency will evaluate and adjust launch opportunities and alternate dates based on progress at the pad and to align with other planned activities, including DART’s planned impact with an asteroid, the west coast launch of a government payload, and the launch of Crew-5 to the International Space Station.
Listen to a replay of today’s media teleconference on the status of the Artemis I mission. Artemis I is an uncrewed flight test to provide a foundation for human exploration in deep space and demonstrate our commitment and capability to extend human existence to the Moon and beyond. Author NASAPosted on Categories Uncategorized
Teams Continue to Review Options for Next Attempt, Prepare to Replace Seal
After standing down on the Artemis I launch attempt Saturday, Sept. 3 due to a hydrogen leak, teams have decided to replace the seal on an interface, called the quick disconnect, between the liquid hydrogen fuel feed line on the mobile launcher and the Space Launch System (SLS) rocket while at the launch pad.

Performing the work at the pad requires technicians to set up an enclosure around the work area to protect the hardware from the weather and other environmental conditions, but enables engineers to test the repair under cryogenic, or supercold, conditions. Performing the work at the pad also allows teams to gather as much data as possible to understand the cause of the issue. Teams may return the rocket to the Vehicle Assembly Building (VAB) to perform additional work that does not require use of the cryogenic facilities available only at the pad.
To meet the current requirement by the Eastern Range for the certification on the flight termination system, NASA would need to roll the rocket and spacecraft back to the VAB before the next launch attempt to reset the system’s batteries.
Additionally, teams will also check plate coverings on other umbilical interfaces to ensure there are no leaks present at those locations. With seven main umbilical lines, each line may have multiple connection points. Author NASAPosted on Categories Uncategorized
NASA to Stand Down on Artemis I Launch Attempts in Early September, Reviewing Options
After standing down on today’s Artemis I launch attempt when engineers could not overcome a hydrogen leak in a quick disconnect, an interface between the liquid hydrogen fuel feed line and the Space Launch System (SLS) rocket, mission managers met and decided they will forego additional launch attempts in early September.
Over the next several days, teams will establish access to the area of the leak at Launch Pad 39B, and in parallel conduct a schedule assessment to provide additional data that will inform a decision on whether to perform work to replace a seal either at the pad, where it can be tested under cryogenic conditions, or inside the Vehicle Assembly Building.
To meet the requirement by the Eastern Range for the certification on the flight termination system, currently set at 25 days, NASA will need to roll the rocket and spacecraft back to the VAB before the next launch attempt to reset the system’s batteries. The flight termination system is required on all rockets to protect public safety.
During today’s launch attempt, engineers saw a leak in a cavity between the ground side and rocket side plates surrounding an 8-inch line used to fill and drain liquid hydrogen from the SLS rocket. Three attempts at reseating the seal were unsuccessful. While in an early phase of hydrogen loading operations called chilldown, when launch controllers cool down the lines and propulsion system prior to flowing super cold liquid hydrogen into the rocket’s tank at minus 423 degrees F, an inadvertent command was sent that temporarily raised the pressure in the system. While the rocket remained safe and it is too early to tell whether the bump in pressurization contributed to the cause of the leaky seal, engineers are examining the issue.
Because of the complex orbital mechanics involved in launching to the Moon, NASA would have had to launch Artemis I by Tuesday, Sept. 6 as part of the current launch period. View a list of launch windows here. Author Rachel KraftPosted on Categories Artemis 1, Artemis ITags Artemis I
Artemis I Launch Attempt Scrubbed
The launch director waived off today’s Artemis I launch attempt at approximately 11:17 a.m. EDT. Teams encountered a liquid hydrogen leak while loading the propellant into the core stage of the Space Launch System rocket. Multiple troubleshooting efforts to address the area of the leak by reseating a seal in the quick disconnect where liquid hydrogen is fed into the rocket did not fix the issue. Engineers are continuing to gather additional data. Author Rachel KraftPosted on Categories Artemis 1, Artemis ITags Artemis I
Liquid Hydrogen Leak Detected Once Again
After the third troubleshooting attempt, the liquid hydrogen leak has occurred again. Teams are discussing next steps. Author Rachel KraftPosted on Categories Artemis 1, Artemis ITags Artemis I
Liquid Hydrogen Flows Again to Core Stage Tank
After warming up the area of the liquid hydrogen leak, engineers are once again flowing liquid hydrogen to the core stage. Author Rachel KraftPosted on Categories Uncategorized
Engineers Warming Up Area of Leak to Attempt Resealing, Core Stage LOX in Replenish
Engineers are continuing troubleshooting efforts to address a liquid hydrogen leak in a cavity in the quick disconnect where the flight side and ground side plates join. They once again will attempt to warm up the quick disconnect to try to reset the seal.
The liquid oxygen tank of the core stage is full and is being replenished as some of the super cooled propellant boils off. Author Rachel KraftPosted on Categories Artemis 1, Artemis ITags Artemis I
Reoccurrence of Liquid Hydrogen Leak Detected
A liquid hydrogen leak has reoccurred again in a cavity between the ground and flight side plates of a quick disconnect in the engine section. Teams are discussing additional troubleshooting efforts. Author Rachel KraftPosted on Categories Artemis 1, Artemis ITags Artemis I
Liquid Hydrogen Flow to Core Stage Resumes
Launch controllers have started flowing liquid hydrogen to the core stage again after troubleshooting the reoccurrence of a leak. This time engineers attempted to reseat the seal in a quick disconnect cavity where the leak occurred by applying pressure to it with helium. Author Rachel KraftPosted on Categories Artemis 1, Artemis I, UncategorizedTags Artemis I
Teams Troubleshoot Reoccurrence of Liquid Hydrogen Leak
As engineers increased the pressure on the flow of liquid hydrogen into the core stage, a leak reoccurred. Engineers will attempt to reseat the seal in the quick disconnect cavity where the leak has been detected. This time they will stop flowing liquid hydrogen to the tank, close the valve used to fill and drain it, then increase pressure on a ground transfer line using helium to to try to reseal it.
Launch controllers are continuing to flow liquid oxygen to the core stage. Author Rachel KraftPosted on Categories Artemis 1, Artemis ITags Artemis I
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Artemis is the first step in the next era of human exploration. Together with commercial and international partners, NASA will establish a sustainable presence on the Moon to prepare for missions to Mars. This blog will be a source of information on Artemis launch and exploration progress, covering updates across our science, technology and human exploration programs. Once we’re ready to fly, check out this blog for launch updates and other mission operations.
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- Repair Work Underway, Preparations Continue for Next Launch Opportunity
- Teams Continue to Review Options for Next Attempt, Prepare to Replace Seal
- NASA to Stand Down on Artemis I Launch Attempts in Early September, Reviewing Options
- Artemis I Launch Attempt Scrubbed
- Liquid Hydrogen Leak Detected Once Again
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