NASA Successfully Hot Fires RS-25 Engine for Artemis IV Mission

NASA successfully conducted a hot fire of RS-25 engine No. 2063 on January 22 at the Fred Haise Test Stand at NASA’s Stennis Space Center in Mississippi. This milestone clears the way for the engine to be installed for the agency’s upcoming Artemis IV mission.

The RS-25 engines are a critical part of NASA’s Space Launch System (SLS) rocket, which will carry astronauts to the Moon as part of the Artemis campaign. Engine No. 2063 was originally installed on the SLS core stage for Artemis II but was removed in 2025 due to a hydraulic leak in the engine’s main oxidizer valve actuator.

Following NASA’s standard procedures, engineers replaced the faulty actuator. Because engines that undergo significant repairs must be tested before flight, the RS-25 engine was fired for a five-minute test at up to 109% of its rated power level. This “confidence test” confirms the engine is flight-ready.

The hot fire test was conducted by a team of operators from NASA, L3Harris Technologies, and Sierra Lobo, Inc., the Stennis test operations contractor. The data collected during these tests helps ensure that all RS-25 engines are proven and reliable before being installed on the SLS rocket.

With the successful test complete, engine No. 2063 is scheduled for installation on the SLS core stage for Artemis IV. NASA is also targeting a February launch for Artemis II, the first crewed mission under the Artemis program, which will send four astronauts around the Moon and back using four RS-25 engines and a pair of solid rocket boosters to lift the Orion spacecraft with over 8.8 million pounds of thrust.

The Artemis campaign aims to return humans to the Moon to unlock economic opportunities, advance scientific discovery, and prepare for future crewed missions to Mars.

Source: nasa.gov