The Register by Richard Speed 10/4/2023
NASA will run out of RS-25s to drop into the ocean unless the production line restartsA test run of the engines powering NASA's Moon rocket is due to kick off this week, an essential milestone since the Space Shuttle cast-offs will need to be replaced – beginning with Artemis V.
NASA's Artemis uses parts left over from the Space Shuttle program. It is notable for having managed to turn the Space Shuttle Main Engines from marvels of reusability into disposable units to be dumped into the ocean during launch, along with the rest of the core stage.
However, only a finite number of engines are available, and NASA has contracted Aerojet Rocketdyne to restart production of the RS-25 engine.
More:
https://www.theregister.com/2023/10/04/space_shuttle_engine_test/
