An important milestone has been reached at the NASA Stennis Space Center as part of the preparation for testing the next stage of the Space Launch System (SLS) rocket for future missions to the moon under the Artemis program. Specialists at the center have successfully completed a two-week installation of an interstage compartment simulator on the Thad Cochran test stand, which began on October 10th, 2024. This component will serve as a protective upper stage compartment for the Artemis missions. The Research Upper Stage (EUS) was manufactured by Boeing at the Michoud Assembly Facility in New Orleans and will be a part of an upgraded version of the Block 1B SLS rocket designed for NASA's ambitious deep space exploration missions. The new EUS will replace the existing cryogenic propulsion system and will feature a single engine capable of delivering up to 27 tons of cargo and crew to lunar orbit. The upper stage will be equipped with four RL10 engines manufactured by L3Harris. Thanks to this upgrade, the payload capacity will increase by 40%, up to 38 tons when flying with a crew, or 42 tons without a crew. The simulator, installed on the test stand, weighs 103 tons and has a diameter of 9.4 m and a height of 10 m. It will protect the electrical and motor systems of the EUS during the Green Run test series and will also serve as a system for diverting the thrust generated by the four engines, which is estimated to be 44,000 kg, back to the test bench.