The engine controller unit needed a "refresh" to provide the capability necessary for four RS-25 engines to power the core stage of NASA's new rocket, the Space Launch System (SLS), to deep space. An engineering model RS-25 controller is being tweaked and tested at NASA Marshall. At one of the center's test facilities, engineers are simulating the RS-25 in flight, using real engine actuators, sensors, connectors, and harnesses.
A second engineering model controller and RS-25 engine also recently were installed on a test stand at NASA's Stennis Space Center. Pending final preparation and activation work, the engine test series is anticipated to begin this year.