NASA Tests RS-25 Engine for 500 Seconds at Stennis

NASA Stennis teams hot-fired RS-25 engine No. 10001 on October 21 at Stennis Space Center near Bay St. Louis, Mississippi. The test lasted 500 seconds, the same duration NASA says RS-25 engines fire during an SLS launch, and reached 111% power.

The developmental RS-25 engine ran for 500 seconds at 111% power.

What has been confirmed

NASA confirmed that engine No. 10001 is a developmental engine and is not intended for flight. NASA and its prime engine contractor, L3Harris Technologies, used the test to gather data for work on engine performance and reliability. NASA says the four RS-25 engines used for each Artemis mission provide up to 2 million pounds of combined thrust, helping propel the SLS rocket at launch. NASA also says it tests RS-25 engines at Stennis to establish flight readiness before use.

Why it matters

The 500-second run matches the engine firing duration NASA describes for an SLS launch, while the 111% power level gives the teams test data above that engine's 100% reference rating. The work supports development of the propulsion system that sends Artemis missions beyond Earth orbit.

FlyMarshall context

Commercial aircraft and launch vehicles serve different purposes, but both depend on propulsion systems that teams test and validate before operation. NASA's Stennis test program provides a ground-based way to assess RS-25 engines; the flight-use engines undergo testing there before they fly.

What happens next

NASA and L3Harris will use data from the test to support engine performance and reliability improvements. NASA has not announced a further test date for engine No. 10001 in the cited material.