SLS Hot Fire Test Ends After Just One Minute

The much-anticipated hot fire test of the Space Launch System (SLS) core stage ended today after about one minute instead of the scheduled eight minutes.  NASA is assessing the situation before deciding on next steps.  What impact it will have on  prospects to launch the first SLS this year, three years later than originally promised, is undetermined.

The test at Stennis Space Center, Mississippi got underway at 5:27 pm ET.  Smoke billowing from the enormous test stand to which the core stage is attached was just what everyone expected as the four RS-25 engines came to life.

The test was intended to last for 485 seconds (8 minutes 5 seconds) although Boeing’s John Shannon said during a press conference on Tuesday that they would have most of the data they needed after just 250 seconds.  Boeing is the prime contractor for SLS.  Aerojet Rocketdyne builds the engines. Designed to be reusable, they were originally used in the space shuttle program and all have flown to space more than once.

Just before 60 seconds, however, a member of test control team is heard saying there was an “MCF on engine 4.”  The flight director then asks “we still have four good engines, right?” and the reply seems to be yes.  The test continues for a few more seconds and then a shutdown occurs at 67.2 seconds.

Wayne Hale, a former NASA shuttle flight director, tweeted that MCF refers to a Major Component Failure and was “not a call” he ever wanted to hear.

Well MCF was not a call this ascent flight director ever wanted to hear: Major Component Failure is detected by the SSME controller.

— Wayne Hale (@waynehale) January 16, 2021

At a NASA press briefing this evening, few details were available as engineers begin their assessment of what went wrong.  John Honeycutt, NASA’s SLS program director, added only that a “flash” was detected at the interface of the thermal protection blanket for engine 4 just before automated systems triggered the shutdown. At that point “the engine controller sent a command to the core stage controller to shut the vehicle down.”

NASA Administrator Jim Bridenstine was characteristically upbeat, praising the NASA-industry team and insisting what happened was not a failure.  “We’ve got to remember what we’re doing here. We are testing hardware. And when you test you learn things.”  Just getting to the point of conducting this test is a win in his opinion considering years of delays.

In 2014, NASA committed  to the first launch in November 2018. That slipped to December 2019-June 2020, then to mid-late 2021.  More recently, NASA was saying November 2021, but that was premised on completing the Green Run tests and shipping the core stage to Kennedy Space Center (KSC) in mid-January 2021.  At the pre-test briefing on Tuesday, Honeycutt referred only to launching by the end of this year, not in November, if all went well today.

Bridenstine, Honeycutt and NASA Stennis Space Center Director Rick Gilbrech declined to predict whether that first launch might still take place this year since the cause of the shutdown and hence the remedy are not known yet.

They also would not say whether a second test is needed, even though it clearly did not get to the 250 second benchmark cited at Tuesday’s briefing.

Bridenstine is a political appointee and his last day as NASA Administrator will be January 20, the end of the Trump Administration.  A former Navy pilot turned Congressman, he has been a passionate cheerleader for NASA since taking the helm of the agency in April 2018 and of the Trump Administration’s goal, announced in March 2019, of landing the first woman and the next man on the Moon by 2024.

Widespread skepticism that 2024 is achievable technically or budgetarily, especially after Congress provided only 25 percent of the funding needed for the Human Landing System, has not dampened his enthusiasm.

Nor did the results of the test today. He went so far as to call it “a good day” for NASA.  Expressing gratitude to everyone involved, he wants the workforce to feel encouraged.

It’s not everything we hoped that it would be, but this is an important day, and you really have done good work to get us to where we are. So I want people to feel encouraged, because the future is very bright.

Bridenstine said Senators Jerry Moran (R-KS) and Roger Wicker (R-MS) were there with him at the test today. Moran chairs the Senate Appropriations subcommittee that funds NASA and Wicker chairs the Senate Commerce Committee that authorizes NASA activities. But only for the next few days. Democrats will take control of the Senate after Kamala Harris is inaugurated as Vice President and the two new Senators from Georgia take their oaths of office.  NASA largely has bipartisan support in Congress, even if it was not evident at today’s test.  Considering the situation in the country right now with COVID-19 and the January 6 failed insurrection, perhaps that is not surprising.

Note: this article was updated after NASA Administrator Bridenstine issued a tweet on January 17, the day after the test, with the exact time the test started and the engines shutdown.

Green Run @NASA_SLS hot fire, T-0 time at 5:27 pm ET, lasting 67.2 sec. Engine ignition at 6 sec. prior to T-0, in sequence about 120 milliseconds apart. Core stage & engines in good shape. More to come this week on Artemis blog.

— Jim Bridenstine (@JimBridenstine) January 18, 2021