See NASA's massive SLS moon rocket fire up (and shut down early)

Before the first major Artemis mission takes off, NASA needs to prove its huge rocket system is up to the task with a spectacular "Green Run" hot fire test.

Amanda Kooser
Freelance writer Amanda C. Kooser covers gadgets and tech news with a twist for CNET. When not wallowing in weird gear and iPad apps for cats, she can be found tinkering with her 1956 DeSoto.
Amanda Kooser
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The latest SLS Green Run tests are taking place at NASA's Stennis Space Center in Mississippi.


One of NASA's main goals for 2021 is to launch Artemis I, an uncrewed moon mission meant to show that the Orion spacecraft and Space Launch System rocket can safely send humans to our lunar neighbor. But first, NASA made some noise with a fiery SLS test on Saturday.

NASA was nearing the end of the Green Run test series that puts the core stage through its paces before it actually launches off this rock sometime in the future. The agency describes the core stage as "the backbone of the SLS rocket."

The eighth part of the test series was set for Saturday, when NASA initiated an exciting hot fire. NASA TV provided live coverage that showed the four huge engines firing up. You can rewatch the action below.

The test was designed to simulate launch conditions for the RS-25 engines and was meant to last up to eight minutes. NASA ended the test early, a little over a minute into the main event. The engines appeared to shut down safely.  

"Teams are assessing the data on early engine shutdown," NASA tweeted shortly after the test.

Test fires are a lot of fun, as we saw last year when an SLS booster lit up the Utah desert and turned sand into glass. Despite the brevity of the core stage test, it was quite a sight to see the billowing output of the raging engines. 

SLS has seen delays during its development, but it's still at the heart of NASA's ambitious plans to take humans back to the moon by 2024 through the Artemis program. A report from last year calls that date into question based on the costs of the program, the SLS setbacks and scheduling impacts from the coronavirus pandemic.

Beyond Apollo: See NASA aim for the moon with Artemis 2024

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The SLS Green Run test took place at the Stennis Space Center in Mississippi, and it came after NASA worked through an unexpected issue with a previous test, a wet dress rehearsal that "marked the first time cryogenic, or super cold, liquid propellant was fully loaded into, and drained from, the SLS core stage's two immense tanks."

The wet dress rehearsal also cut off early, but NASA tracked the problem down to a timing issue that was later corrected. After analyzing what happened with this latest test, NASA hopes it'll still be on track for a possible late 2021 launch of Artemis I. 

Each successful test puts the moon a little closer in reach of human hands.