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NASA test fires SLS rocket ahead of move to Florida, but engines shut down early

Emre Kelly
Florida Today

NASA's rocket charged with taking the agency back to the moon fired its four main engines Saturday afternoon, but the test in Mississippi was cut short after a malfunction caused an automatic abort.

The 212-foot Space Launch System core stage fired its four RS-25 main engines at Stennis Space Center just before 5:30 p.m. Eastern time, sending a plume of exhaust towering above the B-1/B-2 test stand. The NASA center is located about 30 miles northeast of New Orleans.

"We did get an MCF on engine four," a control room member said less than a minute into the test fire, using an initialism that stands for "major component malfunction."

"Copy that, but we're still running," another official said. "Still have four good engines, right?"

The engines fired for 12 more seconds after the exchange before an automatic, computer-controlled shutdown was called. The test was meant to last eight minutes – the full duration needed for the booster during its Artemis program liftoff – but only ran about a minute.

"I know not everybody is feeling as happy as we otherwise could because we wanted to get eight minutes of a hot fire and we got over a minute," NASA Administrator Jim Bridenstine told reporters during a post-test briefing. "But today we got lots of data."

Prime contractor Boeing previously said the test would need to run at least 250 seconds, or more than four minutes, for teams to gather enough data to move forward with transport to Kennedy Space Center and launch sometime before the end of the year. An exact plan moving forward, which could mean a second test and delay before transport to Florida, has not yet been determined.

NASA test fired the four RS-25 engines on its Space Launch System on Saturday, Jan. 16, 2021, at Stennis Space Center in Mississippi. The test, meant to run eight minutes, ended after a minute due to technical issues.

"It depends on what the anomaly was and how challenging it's going to be to fix it," Bridenstine said. "It could be that it's something easily fixable and we could feel comfortable going down to the Cape. It's also true that we could find a challenge that will take more time."

If teams do need test again, it could take up to a week for Stennis to restock its supply of propellants for the core stage, which uses a massive amount of liquid hydrogen and liquid oxygen. A swap of the affected engine, meanwhile, could be performed at Stennis but would likely further stretch the timeline.

Saturday's firing was the last milestone in the "Green Run" series of testing, which has eight phases. Once complete, the core stage will be loaded onto a barge and shipped from Mississippi to a dock near the Vehicle Assembly Building at KSC.

Bridenstine said there isn't enough data at this point to know whether or not SLS will fly in 2021. When it does launch on Artemis I, SLS will boost an uncrewed Orion capsule toward the moon for a weeks-long test flight, setting the stage for future Artemis missions with astronauts on board.

The Boeing-built core stage, under development for nearly a decade, uses previously flown space shuttle main engines. Combined, all four launched a total of 25 shuttle missions including the last flight – STS-135 – in July 2011.

NASA said the RS-25s have been upgraded and refurbished since their last missions and the agency has placed an order with Aerojet Rocketdyne, recently acquired by Lockheed Martin, for 24 brand new versions.

Contact Emre Kelly at aekelly@floridatoday.com or 321-242-3715. Follow him on Twitter, Facebook and Instagram at @EmreKelly. Support space journalism by subscribing at floridatoday.com/specialoffer/.

Launch Monday, Jan. 18

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