An SLS engine burns propellant (left), then abruptly shuts down (right) during a hot fire test on January 16, 2021. NASA TV NASA encountered an engine problem during a critical test of the core stage of its moon rocket on Saturday. The rocket, called Space Launch System, was scheduled to launch in November 2021, kicking off the Artemis program and setting NASA up to send humans back to the moon for the first time since 1972. This engine issue could delay that launch, and push back the timeline for the next crewed moon mission. Visit Business Insider's homepage for more stories. This is a developing story.