Updated 8:05 p.m. Eastern with comments from post-test briefing.
WASHINGTON — NASA completed a successful static-fire test of the core stage of the Space Launch System March 18, two months after a similar test was cut short by technical problems.
The SLS core stage, mounted on a test stand at the Stennis Space Center, ignited its four RS-25 engines at 4:37 p.m. Eastern. The engines fired for approximately 8 minutes and 20 seconds before performing a controlled shutdown, as expected.
Initial analysis of the data showed that the stage performed as expected. “Everything that we’ve seen in the test today looked nominal,” John Honeycutt, NASA SLS program manager, said at a briefing about two hours after the test.
“We collected a lot of data today,” John Shannon, vice president and SLS program manager at Boeing. “It just gives us great confidence that the vehicle, as designed, can handle exactly what it was designed for. The vehicle really performed like a champ today.”
The test ran the full planned duration of the burn, the same as on a launch of the SLS. NASA officials said before this test that they needed the burn to last about four minutes to collect the data they needed to meet all the test milestones, but that they would continue beyond that point to a full-duration burn if it was going well.
“What we were looking for past the four-minute mark was some of our secondary objectives,” said Julie Bassler, manager of the SLS stages office at NASA’s Marshall Space Flight Center. That included another engine gimballing test and throttling the engines to withstand additional loads.
The upbeat mood, which included applause in the control room when the test ended, was different from the first Green Run static-fire test Jan. 16, when the engines shut down after just 67 seconds. Engineers determined that the hydraulic system in one engine hit “intentionally conservative” limits in flight software, triggering the shutdown. NASA decided later in January to perform a second static-fire test to collect data not obtained in the first test.
If the test was indeed successful, NASA will move ahead with preparing the core stage to ship to the Kennedy Space Center, a process that will take about a month. Once at KSC, workers will integrate the core stage with its two five-segment solid rocket boosters, upper stage and Orion spacecraft for the Artemis 1 uncrewed mission. Bassler said at the post-test briefing that she expected the core stage to arrive at KSC by the end of April.
NASA had been planning that launch for November, but in a March 17 interview, NASA Acting Administrator Steve Jurczyk acknowledged that technical problems, as well as delays caused by the pandemic and tropical weather last year, had consumed most of the margin in the schedule for a November launch.
NASA will evaluate that schedule in the next few weeks, he said, and either stick with the November date or push the launch back. “I think in a few weeks we’ll know if November is possible or we need to push it out maybe a month or two,” he said.
At the briefing, Jurczyk emphasized the importance of this test as a major step towards the Artemis 1 launch. “This is a major milestone in advancing our goals and objectives for Artemis,” he said. “This test will allow us to continue the integration of the Space Launch System.”
“We take this a step at a time,” said Tom Whitmeyer, NASA deputy associate administrator for exploration systems development. He declined at the briefing to set a specific date for the Artemis 1 launch, citing the work ahead to integrate the vehicle and go through pre-launch activities, including some first-time activities. “We’re looking for opportunities this year” to launch, he said.
The test was watched closely by members of Congress. “I commend the agency for making the decision to conduct a second hot fire test in order to ensure the core stage is ready for its first flight,” said Rep. Eddie Bernice Johnson (D-Texas), chair of the House Science Committee, in a statement congratulating NASA on the successful test.
“Today’s successful SLS test brings us one critical step closer to returning to the moon and, someday, landing humans on Mars,” said Rep. Don Beyer (D-Va.), chair of that committee’s space subcommittee, in a statement. “After years of development, it’s gratifying to see important and encouraging progress in this key system, which we hope will eventually open opportunities for other scientific missions in addition to NASA’s Moon-Mars program.”