NASA Runs 500-Second RS-25 Engine Test for Future Artemis Hardware

Launch Catch-Up — Test Conducted October 21, 2026

NASA said it fired a developmental RS-25 engine for 500 seconds at its Stennis Space Center in Mississippi on October 21, matching the duration those engines operate during a Space Launch System launch.

Operators brought engine No. 10001 to a 111% power level, which NASA described as the thrust setting required for newly produced engines to send SLS and the Orion spacecraft into orbit.

The test on the Fred Haise stand focused on acceptance testing flight components for later Artemis missions and evaluating a new thermal protection system for the engine nozzle.

The developmental engine itself will not fly. NASA said the ground firing provides performance and reliability data for the agency and prime contractor L3Harris Technologies.

Four RS-25 engines work together on an SLS launch, producing up to 2 million pounds of combined thrust. NASA said engines undergo testing at Stennis before flight. The October 21 firing was a hardware test, not a spacecraft launch or a new mission-date announcement.

Sources NASA — October 21 RS-25 test account: https://www.nasa.gov/image-article/rs-25-engine-test-in-support-of-future-artemis-missions/