The crucial test, known as the wet dress rehearsal, simulates every stage of launch without the rocket leaving the launchpad. This process includes loading propellant, going through a full countdown simulating launch, resetting the countdown clock and draining the rocket tanks.
After three attempts of the wet dress rehearsal in April, the rocket stack was rolled back into the Vehicle Assembly Building on April 26 to address issues that cropped up during the test attempts.
So far, the team has been working on replacing a faulty check valve on the rocket’s upper stage that created a helium leak and repairing the source of a tail service mast hydrogen leak. Meanwhile, Air Liquide, which supplies gaseous nitrogen to the launchpad, has been upgrading its pipeline configuration to better support the testing and launch of Artemis I.
When inspecting the check valve, the team found a small piece of rubber that prevented it from sealing correctly, said Jim Free, associate administrator for NASA’s Exploration Systems Development Mission Directorate, during a news conference on Thursday.
No issues were found with the valve, and engineers are investigating the source of the rubber since it wasn’t initially part of the valve, Free said. The team has also narrowed down the potential causes for the hydrogen leak.
Once the rocket stack rolls back out to the launchpad in late May, it will take between 12 and 14 days before the rocket can go through another wet dress rehearsal, which could occur in early to mid-June, Free said.
“We’ve done a lot of work to get the rocket ready to roll back out to the launchpad,” said Cliff Lanham, senior vehicle operations manager for NASA’s Exploration Ground Systems Program at Kennedy Space Center. “Stopping at the VAB is a pit stop to come back in, do what we need to do and get back out to the pad as quickly as possible. So we’re working hard to meet that goal.”
The Artemis team is now looking at launch windows for sending Artemis I on its journey to the moon in late summer: between July 26 and August 9, August 23 to August 29 and September 2 to September 6.
“We also want to be realistic and upfront with you that it may take more than one attempt to get the procedures where we need them for a smoother launch count that gives us the best chance to make our launch windows,” Free said.
Once the Artemis rocket stack completes its wet dress rehearsal, it will roll back into the building to wait for launch day.
There is a long history behind the arduous process to test new systems before launching a rocket, and what the Artemis team is facing is similar to what the Apollo and shuttle era teams experienced, including multiple test attempts and delays before launch.
The results of the wet dress rehearsal will determine when the uncrewed Artemis I will launch on a mission that goes beyond the moon and returns to Earth. This mission will kick off NASA’s Artemis program, which is expected to return humans to the moon and land the first woman and the first person of color on the lunar surface by 2025.