NASA is conducting the third hot fire as part of the final round of certification testing ahead of production of an updated set of the engines for the SLS (Space Launch System) rocket.
Crews will gimbal, or pivot, the RS-25 engine around a central point to test "steering" of the @NASA_SLS
rocket.
The Artemis program is a US government-funded crewed spaceflight program that has the goal of landing "the first woman and the next man" on the Moon, specifically at the lunar south pole region by 2024.