The fourth attempt of the latest pre-launch test began on Saturday and the missile tanks were full on Monday.
The critical test, known as wet wear training, simulates every stage of the launch without the rocket leaving the launch pad at Kennedy Space Center in Florida.
This process includes loading ultra-cooled boosters, running a full countdown simulating a launch, resetting the countdown clock, and draining missile tanks.
The results of the wet-clothes training will determine when Artemis I embarks on a mission beyond the Moon and back to Earth. This mission will launch NASA’s Artemis program, which is expected to return humans to the Moon and land the first woman and first person of color on the Moon by 2025.
Three previous test attempts in April failed and ended before the missile could be fully loaded with fuel due to multiple leaks. NASA says these errors have now been corrected.
The NASA team rolls a 322-foot (98 m) stack of Artemis I rockets, including the Space Launch System and the Orion spacecraft, to the launch pad at Kennedy Space Center in Florida on June 6.
Wet test steps
The rehearsal kicked off at 5 p.m. ET on Saturday with a “call for the seasons” – when all teams associated with the mission arrive at their consoles and signal that they are ready to begin testing and a two-day countdown begin.
Preparations for the weekend prepared the Artemis team to begin loading propellant into the rocket’s core and upper stages on Monday morning.
The tanks were suspended Monday morning due to an identified problem with the backup nitrogen gas supply. The release team replaced the valve that was causing the problem. To ensure that the backup source works as expected, it was replaced as the primary source for testing.
The comment was lifted at 9:28 a.m. ET. Liquid oxygen, cooled to minus 297 degrees Fahrenheit (minus 182 degrees Celsius), and liquid hydrogen were used to fill the center stage before moving to the upper stage of the rocket. The opening was visible from the missile throughout the operation.
The base floor was nearly full and the team was filling the top floor when several issues arose after 2:00 p.m. ET.
The team detected a hydrogen leak in a core stage fast split line. Their first choice didn’t work out and they studied Options for sealing the leak.
Something from the glowing chimney, where excess liquid hydrogen from the rocket is burned with a propane flame, caused a small fire in the grass toward a dirt road. The crew monitored the grass fire and expected the fire to break out once it reached the dirt road.
The test exceeded the scheduled 30-minute waiting period, which was extended as engineers tried to find solutions to the hydrogen leak.
The Artemis team decided to go ahead with a countdown, while masking the issue of the hydrogen leak, “to move forward with our wetsuit trial run today. ‘today,’ according to a tweet from NASA’s Earth Exploration Systems.
The 10-minute countdown started at 7:28 p.m.
There are normally two countdowns during the rehearsal. First, team members typically go through a 33-second countdown to launch, then pause the cycle. The clock is reset, then the countdown begins again and lasts until approximately nine seconds before launch.
Monday’s brief countdown ended prematurely with 29 seconds remaining on the countdown clock. A computer science of the SLS missile led to a hack, but the exact science has not been shared. Ahead of the countdown, the team said that if computers participating in the countdown detect a hydrogen leak, it could be similar to a check engine light that forces the countdown to stop sooner. .
Once the countdown stopped, the Artemis team worked to ensure the safety of the vehicle.
It’s “definitely a good day for us,” Charlie Blackwell Thompson, Artemis launch manager for NASA’s Earth Exploration Systems program, said after hitting several milestones set in wet rag goals, like putting the entire rocket into a tank and pass the countdown.
The next steps, she said, would be to assess all the data gathered from the test, including any issues, and develop a plan for moving forward.
Blackwell-Thompson said previous attempts at wet rag training had already achieved many goals in preparing the missile for launch.
There’s a long history behind exhaustive testing of new systems before launch, and the Artemis team faces similar experiences to those of the Apollo and Space Shuttle teams, including multiple test attempts and delays.