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<\/p>\nWith the completion of another single-engine RS-25 development test, Aerojet Rocketdyne is now refurbishing five engines at the Stennis Space Center in Mississippi for their next use. After the second test firing of the Retrofit 2 series in the A-1 Test Stand on April 6, development engine 0528 is going through a streamlined refurbishment prior to its next firing as a part of the production restart Retrofit 2 test series.<\/p>\n
In parallel, the four RS-25 engines installed on the first Space Launch System (SLS) Core Stage in the nearby B Test Stand are being taken through a longer refurbishment checklist for flight engine hardware. The next planned ignition for those Core Stage engines is for the first SLS launch on the Artemis 1 mission to send an Orion spacecraft to lunar orbit.<\/p>\n<\/p>\n
Production restart testing resumes<\/p>\n
Hot-fire testing of the two current RS-25 ground test engines resumed on April 6 with the second test in the Retrofit 2 series. The test team of engineers from NASA, Aerojet Rocketdyne, and Stennis facility prime contractor Syncom Space Services fired engine 0528 (E0528) for 500 seconds.<\/p>\n
Aerojet Rocketdyne (AR) said the primary objectives of the test were to demonstrate engine thrust vector control (TVC) and operating characteristics of the new oxidizer preburner oxidizer valve (OPOV) retrofitted on E0528.<\/p>\n
The RS-25 engines support gimbaling, but the muscle itself is provided externally. The single-engine, hydrogen-oxygen A-1 test stand was modified a few years ago to support gimbaling the RS-25 and other possible future customers. The ground-side TVC system has been thoroughly tested, but the April 6 test was its first operation during an engine test-firing.<\/p>\n
AR noted that the demonstration included 118 cumulative seconds of engine gimbaling by the new test stand system.<\/p>\n
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Credit: NASA\/SSC.<\/p>\n
(Photo Caption: Aerojet Rocketdyne is now processing the five RS-25 engines shown in this composite image. Engine 0528 on the left is a development engine that is ground-testing newly-produced engine components retrofitted to its powerhead. Engines 2045, 2056, 2058, and 2060 are seen firing during one of the SLS Core Stage Green Run Hot-Fire tests; all five engines were originally Space Shuttle Main Engines used by the program for flight operations and engineering support.)<\/em><\/p>\n The Retrofit 2 test series is the second of four in support of certifying the restart and modernization of RS-25 engine production. Sixteen Block II Space Shuttle Main Engines (SSME) were retained from the Space Shuttle Program and will support the first four SLS launches.<\/p>\n The SSMEs were adapted largely as-is to the higher SLS operating requirements, which were recently demonstrated in the second Core Stage Green Run Hot-Fire test in the B-2 position of the B Test Stand at Stennis on March 18. SLS is an expendable vehicle and new engine builds will be needed by the program, first as spares and then for flight beginning with the fifth SLS launch.<\/p>\n Manufacturing improvements will allow the production restart engines to operate at 111 percent of the original SSME rated power level; during Shuttle, the engines operated as high as 104.5 percent, and the RS-25 adaptation engines will fly their last missions at 109 percent, just as they ran in the Green Run Hot-Fire tests.<\/p>\n<\/p>\n