Since replacing an engine controller on RS-25 engine number four that is on the Space Launch System (SLS) rocket core stage, NASA, and lead engines contractor Aerojet Rocketdyne, have performed a series of tests to ensure the engines and controllers are ready to support the Artemis I mission. All four engine controllers performed as expected during power up, as part of the Artemis I Core Stage engineering tests.
Aerojet Rocketdyne and its manufacturer of the engine flight controller, conducted numerous tests on the faulty engine four controller and determined the cause to be a faulty memory chip. The device is used only during the controller start-up sequence and has no impact on controller operations beyond that point. There is no indication of faulty memory chips on the other three engines, and therefore no related constraints to the wet dress rehearsal or launch.
Kennedy teams are completing remaining SLS pre-flight diagnostic tests and hardware closeouts, including testing the flight termination system on the SLS and installing instrumentation on the twin solid rocket boosters, in advance of rolling the rocket and spacecraft to Launch Pad 39B for the first time next month for a final test before launch. This final test, known as the wet dress rehearsal, will run the launch team through operations to load propellant into the rocket’s tanks and conduct a full launch countdown.
During the test at the launch pad, engineers will be on duty in the Launch Control Center and in other stations where they will work during the Artemis I launch. They will capture as much data as possible on the performance of all the systems that are part of SLS and the Orion spacecraft as well as the Kennedy ground systems. NASA will set a target launch date after a successful wet dress rehearsal test.