A few days after NASA announced that it was ready to conduct a second static firing test of the primary stage of the Space Launch System, the agency announced on February 22 that the test would be delayed due to a problem with the valve.
NASA said it had postponed the Green Run static firing test, which was scheduled for February 25, after discovering a problem with one of the eight so-called “dominant” fuses associated with the RS-25’s four main stage engines. NASA said in a statement that the valve that supplies liquid oxygen “is not working properly,” but did not explain the problem.
Engineers identified the problem during preparations during the test weekend. NASA said it will work with Boeing, the main contractor for the base stage, “to set a path forward in the coming days and reschedule the hot fire test,” but has not set a new date for the test.
This is not the first time that there has been a problem with the fuse delaying the Green Run test of the primary stage. In November, NASA reported a problem with liquid hydrogen diffusion in the primary stage, requiring workers to design a special tool to fix the valve on the test stand. This, combined with the effects of a tropical storm that passed the Stennis Space Center in late October, has delayed several weeks of stage rehearsal, as the stage is loaded with fuel and a training countdown passes.
The latest announcement of the delay came just three days after NASA and industry officials held a briefing where Confident that they were ready to take a steady fire test on February 25. This included overcoming problems associated with recent winter storms and unusually cold weather at the Mississippi Test Site.
“The team has been working hard on some tough situations.” John Shannon, Vice President and Director of the SLS Program at Boeing, said during the briefing, “We are on a very good path to achieving the 25th.”
In the same briefing, NASA officials said they remained cautiously optimistic that the SLS could make its first launch on the Artemis 1 mission, an unmanned test flight of the Orion spacecraft, before the end of the year despite the long delay in the Green Run test campaign. Tom Whitmire, deputy assistant director for exploration systems development at NASA Headquarters, said the mission could begin as soon as October if all goes well, and then admit that there are likely to be problems along the way.
“First of all, we really need to have these hot flames behind,” he said, pointing to Green Run’s static firing test. “This is the most important thing in front of us.”