Since returning to the Vehicle Assembly Building (VAB), ground systems teams have worked to prepare the Artemis I Space Launch System (SLS) rocket and Orion spacecraft to roll back to Launch Pad 39B in late May to complete the wet dress rehearsal test in the early to mid-June timeframe.
Inside the VAB at NASA’s Kennedy Space Center, engineers replaced a faulty helium check valve on the interim cryogenic propulsion stage that was identified after the second wet dress rehearsal attempt. Engineers have inspected the valve and found a small piece of rubber that prevented the valve from sealing correctly. Teams are looking at possible sources of the debris, but did not see any issues with the valve itself, and plan to test the newly installed valve later this week to confirm it is operating as expected.
Engineers also performed tests to address a hydrogen leak on one of two tail service mast umbilicals between the mobile launcher and the rocket. These umbilicals provide liquid oxygen and liquid hydrogen propellants, as well as electrical connections, from the mobile launcher to the rocket’s core stage during the launch countdown. Teams conducted leak checks on all the joints and tightened several flange bolts, or fasteners that act as a washer to increase the compression strength, that can loosen over time and were the most likely source of the leak. Teams re-tightened the flange bolts on the liquid hydrogen, liquid oxygen, and core stage intertank umbilicals. Engineers have not detected leaks in subsequent testing at ambient air temperature, and will continue to monitor for leaks when loading the super cold propellants at the launch pad.
The supplier that provides gaseous nitrogen for operations during tanking is upgrading its facility to meet the requirements for the next wet dress rehearsal attempt and the Artemis I launch. Teams are on track to complete the work early next week, followed by testing to ensure the system is ready for tanking. During the test, teams pump gaseous nitrogen into dry structures to protect avionics during propellant loading.
Once all major work is completed, teams will retract the working platforms and prepare the integrated SLS rocket and the Orion spacecraft for the second journey to the launch pad. NASA will announce dates for roll to the pad and the next wet dress rehearsal attempt once work is nearing completion inside the VAB.