All Four RS-25 Engines Installed on First SLS Rocket

In a major milestone for NASA’s Space Launch System (SLS), all four RS-25 engines – veterans of the Space Shuttle Program (SSP) – have been installed into the core stage of the rocket that will conduct the maiden flight of NASA’s new monster rocket on the Artemis-1 mission.

SLS will use the full inventory of flight-proven Space Shuttle Main Engine (SSMEs), or RS-25Ds, before exhausting the stock and moving to the RS-25E.

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