Just days after announcing that it was prepared to conduct a second static-fire evaluation of the Space Launch System main stage, the NASA agency announced on February 22 that the evaluation would be postponed due to a valve concern. The Green Run static-fire trial, which had been planned for February 25, has been postponed after NASA discovered an issue with one of the central stage’s eight “prevalves,” which provide propellant to stage’s four RS-25 main engines. NASA stated in a statement that the valve that supplies liquid oxygen was “not functioning correctly” but didn’t clarify the issue.
Engineers discovered the issue when planning for the evaluation over the weekend. NASA stated it would work with Boeing, the core stage’s main contractor, to “define a route forward in the coming days and reschedule the hot fire trial,” but no specific schedule for the assessment has been set.
This isn’t the first period a valve issue has caused the core stage’s Green Run analysis to be postponed. NASA documented an issue with the liquid hydrogen prevalve on main stage in the month of November, necessitating constructing a specific tool to fix the valve on the evaluation stand. The stage’s wet dress rehearsal; the stage is filled with propellant and goes via a practice countdown, was postponed by several weeks due to this, as well as the impact of the tropical storm that flew by the Stennis Space Center in the late October.
The new delay was revealed only three days after the NASA agency and industry authorities held a press conference. They expressed faith that the static-fire analysis would be completed on February 25. At the Mississippi testing facility, this included resolving issues caused by extreme winter storms and extremely cold weather. “The team has been putting in a lot of effort to deal with some tough circumstances. During the meeting, John Shannon, who serves as the vice president as well as SLS program manager at the Boeing, stated, “We’re on target to make the 25th.”
Given the unnecessary delay in the Green Run evaluation campaign, NASA authorities remained pretty hopeful that SLS could deliver its first deployment on the Artemis 1 flight, an uncrewed flight test of the Orion spaceship before the end of the year. Tom Whitmeyer, NASA’s deputy associate administrator in charge of exploration systems development, stated the project could launch as early as October if all goes well but acknowledged that there would almost certainly be hiccups along the way.