The mission team plans to begin Supply of the 322-foot (98 m) Artemis I rocket stack, including NASA’s Space Launch System and Orion spacecraft, Thursday.
The test, known as wet clothes rehearsal, was modified in response to an issue encountered during the third attempt over the weekend. Engineers have determined the helium check valve is not working. The valve is difficult to reach while the missile is sitting on the launch plate, but it can be replaced or repaired later. The modified version of the wet drill is necessary to ensure the safety of the missile’s flight equipment.
Helium is used to purge the engine before loading an extremely cold thruster—which is wet during wet training—while refueling. Check valves allow gas or liquid to flow in one direction to prevent reverse flow. In this case, the non-working portion is about 3 inches long and prevents helium from flowing back out of the rocket.
When the missile’s primary stage tank begins Thursday, the revised test will decompress the valve and upper missile stage with minimal thrust. Previously, the team I planned to fully refuel the primary and upper stages of the rocket, but the valve problem prevents this A step of the procedure during this test.
The results of this rehearsal will determine if there is more Tests must be conducted prior to launch.
“I’m very confident we’ll do a good test Thursday with the modified procedures,” said John Blevins, chief SLS engineer at NASA’s Marshall Space Flight Center in Huntsville, Alabama, during a press conference Monday. “I can’t say I’m glad we had a broken part, but I’m glad we found it when we did before we got into any hacks with a broken part. That’s why we do this comprehensive testing.”
The rehearsal simulates each stage of the launch without the missile actually exiting the launch pad. This includes powering up the SLS rocket and Orion spacecraft, loading ultra-cooled propellant into the rocket’s tanks, performing a full launch simulation countdown, resetting the countdown clock, and drying the rocket tanks.
Tuesdays will begin around 5 p.m. ET with stations calling, a check-in with every team associated with a launch to say testing has begun.
Once this test is complete, the Artemis I rocket will be returned to the Vehicle Assembly Building at the Kennedy Space Center in Florida where teams can analyze and replace the valve if necessary.
The officials said the three previous attempts at rehearsal had already provided valuable information to the team, even as they worked through various issues.
“We completed a lot of the testing requirements that we needed to get out of the wet clothes business,” Tom Whitmer, associate deputy director of exploration systems development at NASA Headquarters, said during a press conference Monday. “We have a few more to get to on Thursday. The massive moon rocket is in good shape and we’re treating it very carefully.”
Although the exact problems identified during the test attempts were not foreseen, they are part of the process when testing a new missile.
“Any new missile that is introduced into a new program like this type of missile goes through these updates and understands how the missile performs,” Whitmer said. “And that’s the kind of thing we’re going through right now.”
“I can say that these probably won’t be the last challenges we’ll face,” Mike Sarafin, Artemis mission manager at NASA Headquarters, said during the conference. “But I am confident that we have the right team in place and the ability to come around and overcome these problems is something we can be proud of.”
The results of training in wet clothes will determine when Artemis I will embark 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 people of color on the moon by 2025.
Sarafin said the current launch window includes June 6 through June 16, June 29 through July 17, and July 26 through August 9.