NASA remains on track for an Artemis I cryogenic demonstration test on Wednesday, Sept. 21. In the days since the previous launch attempt, teams have analyzed the seals that were replaced on an interface for the liquid hydrogen fuel line between the Space Launch System (SLS) rocket and the mobile launcher and adjusted procedures for loading cryogenic, or supercold, propellants into the rocket. Engineers identified a small indentation found on the eight-inch-diameter liquid hydrogen seal that may have been a contributing factor to the leak on the previous launch attempt.  

With new seals, updated cryogenic procedures, and additional ground software automation, teams are now preparing to demonstrate the updates under the same cryogenic conditions the rocket will experience on launch day. During the demonstration, the four main objectives include assessing the repair to address the hydrogen leak, loading propellants into the rocket’s tanks using the new procedures, conducting the kick-start bleed, and performing a pre-pressurization test.  

Based on recent engineering assessments, the new cryogenic loading procedures and ground automation will transition temperatures and pressures more slowly during tanking to reduce the likelihood of leaks that could be caused by rapid changes in temperature or pressure. After the liquid hydrogen tank transitions from the slow fill phase to fast fill, teams will initiate, or “kick-start,” the flow of liquid hydrogen through the engines to begin conditioning, or chilling them down, for launch. After both tanks have reached the replenish phase, the pre-pressurization test will bring the liquid hydrogen tank up to the pressure level it will experience just before launch while engineers calibrate the settings for conditioning the engines at a higher flow rate, as will be done during the terminal count. Performing the pressurization test during the demonstration will enable teams to dial-in the necessary settings and validate timelines before launch day, reducing schedule risk during the launch countdown. 

Call to stations for the demonstration occurred at 5 p.m. EDT Monday. The launch director is expected to give a “go” to begin loading cryogenic propellants into the rocket at approximately 7 a.m. Wednesday. The test is planned to conclude around 3 p.m. after the teams have met the objectives and will not go into the terminal count phase of the launch countdown. Teams may extend the duration of the test should circumstances warrant it.  

During the test, teams will load propellants into both the core stage and upper stage tanks, and Orion and the SLS boosters will remain unpowered. Meteorologists currently predict favorable weather for the test with a 15% chance of lightning within 5 nautical miles of the area, which meets criteria required for the test, and will continue to monitor expected conditions. 

NASA Television will provide live coverage with commentary of the demonstration beginning at 7:15 a.m. Sept. 21. Continuous live video of the Artemis I rocket and spacecraft at Launch Pad 39B remains available on the Kennedy Newsroom YouTube Channel

Artemis I Cryogenic Demonstration Test on Track for Wednesday