NASA Artemis IV SLS Core Stage Hot Fire Test Succeeds
Summary: The SLS core stage for Artemis IV completed a full-duration hot fire test at Stennis Space Center on 2026-07-24, validating RS-25 propulsion performance.
On July 24, 2026, NASA successfully conducted a full-duration hot fire test of the Space Launch System (SLS) core stage designated for the Artemis IV mission on the B-2 test stand at Stennis Space Center in Mississippi. This test represents a critical milestone in the Green Run test series for the SLS core stage, marking significant progress in ground verification before the hardware is shipped to Kennedy Space Center for final assembly.
During the test, the four RS-25 engines ignited according to the pre-programmed sequence and fired for the full planned duration, generating a combined thrust of over 7 million pounds-force. Manufactured by Aerojet Rocketdyne, the RS-25 engines rank among the most powerful liquid-fueled rocket engines ever used. The hot fire validated the propellant feed system, flight computer, software, and the overall performance of the engines integrated with the core stage structure. All parameters were reportedly within expected ranges.
The SLS core stage serves as the backbone of the entire rocket, standing approximately 65 meters tall and carrying liquid hydrogen and liquid oxygen cryogenic propellants to feed the four RS-25 engines. Compared with the core stages used in Artemis I through III, the hardware for Artemis IV features manufacturing optimizations that reflect ongoing efforts by NASA and its industrial partners to reduce per-launch costs.
Following the hot fire test, the core stage will undergo thorough data review and remaining inspections before being transported to Kennedy Space Center for integration with the solid rocket boosters, upper stage, and Orion spacecraft. The Artemis IV mission is currently planned for 2027, aiming to send astronauts to lunar orbit and accumulate experience for subsequent crewed lunar landing missions.