(CNN) — NASA’s Artemis I lunar megarocket could face another attempt at its crucial ground test before launch starting next week, according to NASA officials.
Engineers are testing a 322-foot-tall (98-meter) Artemis I rocket stack, including NASA’s Space Launch System and Orion spacecraft, through its final steps on the launch pad at the Kennedy Space Center in Florida. This Thursday they met a hydrogen leak problem.
The crucial test, known as a wet dress rehearsal, simulates all stages of the launch without the rocket leaving the launch pad. This process includes loading propellant, performing a full countdown simulating launch, resetting the countdown clock, and emptying the rocket’s stores.
A hydrogen leak “prevented” the end of the test
The team was able to load supercold propellant into the SLS rocket’s core stage tanks, but “encountered a liquid hydrogen leak at the tail service mast umbilical that prevented the team from completing the test,” according to the agency.
“After fixing the problem, the team decided to call it a day because when there’s hydrogen leaking, and you have ambient oxygen out there, you just need an ignition source to close the fire triangle. So it was a flammability hazard.” said Mike Sarafin, director of the Artemis mission at NASA headquarters, during a press conference on Friday.
Technicians collected data, drained the tanks and made sure the rocket remained safe and stable. Despite the leak, the team was able to work through a series of critical tests during the third attempt.
“The lunar megarocket is fine,” Sarafin said. “All the issues we’re running into are procedural and lessons learned.”
Now, the testing team is still evaluating how to fix the leak. Troubleshooting started this Friday morning.
The team will “look at these specific areas that we think might be the problem, how we can access them” and determine a path forward, said Charlie Blackwell-Thompson, Artemis launch manager for NASA’s Exploration Earth Systems program. , during a press conference this Friday.
Next trial attempt
In the meantime, the team is preparing for the next potential opportunity of another wet dress rehearsal attempt on April 21, the earliest time the team is comfortable with, Sarafin said. The Artemis team is working closely with SpaceX because the Crew-4 launch is expected to take place at a nearby launch pad on April 23.
Sarafin did not disclose the exact plan for keeping the run on track, given that it has only been 24 hours since the breakout, but said the team is looking at options that are “readily accessible.”
“We’re hoping there’s something here that’s fairly simple and needs to be adjusted or easy to fix, and that we can do it on the platform and in a fairly short timeframe,” Sarafin said. “And then there are a couple of more invasive options and we have to weigh them against a whole host of considerations including putting additional stress on the vehicle.”
The longer the rocket remains on the launch pad, the more it will be subjected to wind and other stress factors while exposed to the elements, not to mention the stress induced by repeated testing. That could determine when the stack re-enters the space center’s Vehicle Assembly Building.
Ambitious mission essays
Asked if it’s possible for Artemis I to launch without completing certain aspects of a full test, the team said it would have to meet an acceptable level of risk. But the ground and flight test programs have not been completed, so the team has not yet reached that consideration, Sarafin said.
The goal of wet dress rehearsal is to learn about problems that can be corrected before being forced to abort a launch attempt, and it’s something the Apollo and shuttle programs also faced, Blackwell-Thompson said.
The first shuttle underwent five or six fuel tests before launch. Also, the shuttle only had one stage, whereas the SLS rocket has a core and upper stage that must be fueled with supercold propellant, making the process even more complex.
Sarafin said the team talks from time to time with staff who worked on the previous programs, comparing the challenges of physics, fluid dynamics, thermodynamics, supercold temperatures, structural stresses and flammability hazards.
“History has shown that it has been a challenge for almost everyone who has done something of this magnitude,” Sarafin said.
The results of the trial will set a date for the launch
The results of the wet dress rehearsal will determine when the uncrewed Artemis I will be launched on a mission that will go beyond the Moon and return 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 first person of color on the lunar surface in 2025.
“But I have no doubt that we will finish the test campaign and be ready to fly,” added Blackwell-Thompson.