The crucial test, known as the wet dress rehearsal, simulates every stage of the launch without the rocket leaving the launch pad. This process includes loading the propellant, performing a full countdown simulating the launch, resetting the countdown clock, and draining the rocket’s fuel tanks.
The team was able to load supercold propellant into the SLS rocket’s core stage tanks, but “encountered a liquid hydrogen leak on the tail service mast umbilical that prevented the team from completing the test,” according to the agency.
“After troubleshooting it, the team decided to shut it down for the day, because when you have hydrogen leaks and you have ambient oxygen, all you need is a source of oxygen. ‘ignition to close the fire triangle. So it was a flammability hazard,’ Mike Sarafin, Artemis mission manager at NASA Headquarters, said on a Friday newscast. conference.
Technicians collected data, emptied tanks and ensured the rocket remained safe and stable. Despite the leak, the team was able to work on a number of critical test items on the third attempt.
“The mega lunar rocket is doing well,” Sarafin said. “Any problems we encounter are procedural and lessons learned.”
Now the test team continues to evaluate how to deal with the leak. Troubleshooting has started Friday morning.
The team will “look at those particular areas that we think might be the problem, how we get to them” and figure out a way forward, said Charlie Blackwell-Thompson, Artemis launch director for the Exploration Ground Systems program. from NASA, during a Friday news item. conference.
In the meantime, the team is preparing for the next potential opportunity in another dress rehearsal attempt on April 21, the first time the team is comfortable with, Sarafin said. The Artemis team is working closely with SpaceX as the Crew-4 launch is scheduled to take place at a nearby launch pad on April 23.
Sarafin did not reveal the exact plan to keep the course on track, given that only 24 hours have passed since the leak, but he said the team is looking at “easily accessible” options.
“We hope there is something that is quite simple and needs to be adjusted or is easily solved, and we can do it on the pad and do it in a pretty short time,” Sarafin said. “And then there are some more invasive options, and we have to weigh those against a whole host of considerations that include putting stress on the vehicle.”
The longer the rocket stays on the launch pad, the more it is subjected to wind and other stressors when exposed to the elements – not to mention the strain induced by repeated testing. This could determine when the pile will be brought back to the Vehicle Assembly Building at the Space Center.
Test challenging missions
When asked if it was possible for Artemis I to launch without completing certain aspects of a full test, the team said it should reach an acceptable level of risk. But the ground and flight test programs aren’t complete, so the team hasn’t reached that consideration yet, Sarafin said.
The purpose of the wetsuit rehearsal is to learn about problems that can be corrected before being forced to abort a launch attempt, and this is something the Apollo and Shuttle programs have also faced, a said Blackwell-Thompson.
There were about five or six refuelings, or wetsuit rehearsals, of the first shuttle before launch, she said. And the shuttle had only one stage, whereas the SLS rocket has a core and an upper stage that must be fed super cold propellant, which makes the process even more complex.
Sarafin said the team speaks occasionally with staff who have worked on previous programs, comparing challenges in physics, fluid dynamics, thermodynamics, super cold temperatures, structural constraints and risks. flammability.
“History has shown that this has been a challenge for virtually anyone who has done something of this magnitude,” Sarafin said.
The results of the dress rehearsal will determine when the uncrewed Artemis I embarks on a mission that will go 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 lunar surface by 2025.
“But there is no doubt in my mind that we will complete the test campaign and be ready to fly,” added Blackwell-Thompson.
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