NASA SLS program manager John Honeycutt revealed how after the one minute-mark, cameras caught a flash on the engine’s protective thermal blanket.
However, its cause and significance are still to be determined.
Space experts believe it is too early to know for certain if a second hot-fire test will be required at Stennis.
Another option for NASA is to conduct another test at NASA’s Kennedy Space Center.
This is the site from which SLS is set to launch the unmanned Artemis 1 Moon mission before the end of 2021.