WASHINGTON – NASA has about three weeks to complete repairs to the Space Launch System upper stage to make the next launch window for the Artemis 2 mission in early April.
NASA announced on February 21 that it would move the SLS and Orion spacecraft from Launch Complex 39B to the Vehicle Assembly Building after helium flow to the Interim Cryogenic Propulsion Stage, or ICPS, was disrupted. The rollback occurred on 25 February.
“We do, however, have the capability to access the booster and core stage at the pad,” Lori Glaze, acting associate administrator for the Exploration System Development Mission Directorate, said at a Feb. 27 briefing.
At the briefing, which focused mainly on broader Artemis architecture changes, NASA provided few details about what caused the disruption to helium flow to the stage. NASA Administrator Jared Isaacman said on February 21 that the problem could have been caused by a final filter between the ground and vehicle systems, a quick-disconnect umbilical interface or a failed check valve inside the stage. The check valve caused a similar problem during Artemis 1, but Isaacman said NASA took steps after that mission to prevent a recurrence.
In a February 26 update, NASA said it had narrowed down possible causes to a seal in the quick-disconnect or check valve.
“The team has worked inside the VAB to streamline a plan for work to give us the best chance for an early April launch,” Glaze said. That window runs from April 1 to 6.
Components suspected of causing helium flow problems will be removed and inspected. “We hope to get to the root cause of this and make changes, not only in the hardware but also in our operating procedures, so that when we go back to the pad we don’t have to face the same problem again,” he said.
Additional maintenance is planned while the vehicle is in the VAB. This includes replacing and retesting the batteries in the rocket’s flight termination system and giving the closeout crew another opportunity to rehearse procedures to prepare the Orion spacecraft for launch. Some objects loaded into Orion will “time out” due to the delay and will be replaced, he said.
Glaze also said workers would replace the seal in the navel that transfers liquid oxygen to the SLS core stage. Similar seals in liquid hydrogen lines were replaced after leaks during a wet dress rehearsal in early February, although NASA did not report issues with liquid oxygen leaks.
During the briefing, NASA did not provide any detailed schedule for completing the work. Glaze said the agency would need “at least a week and a half or more” of work on the pad before it would be ready for launch. This suggests Artemis 2 will need to return to the pad in about three weeks to support the April 1 launch.
Another NASA official called the timeline aggressive.
“The teams have an aggressive schedule,” NASA Deputy Associate Administrator Casey Swails said in a speech at the ASCENDxTexas conference on Feb. 25.
If Artemis is not able to launch as early as April 2, the next opportunity opens on April 30. NASA has not disclosed additional details about that opportunity or a later launch window.
