One of the engines of Space Launch System rocket finished fire test in NASA Stennis research facility.
It was pre-used engine #0528, which was last tested on 2009; according to Steve Wofford, manager of the SLS Liquid Engines Office at Marshall Space Flight Center in Alabama (interview published on Nasaspaceflight.com), it was seventh major RS-25 fire test and second necessary to finish certification procedure. Last test, with 2059 engine, was also conducted in Stennis on A-1 stand on March 2016, but it was not part of the certification process. First test which started certification was performed on August 2015, with engine #0525. According to (interview published on NASASpaceflight.com) Steve Wofford, manager of the SLS Liquid Engines Office at Marshall Space Flight Center in Alabama:
“This test series is a continuation of the broader objectives of the series from last year, and that is basically certifying the engine to the new start and run conditions on SLS versus what it was on Shuttle, [such as] different propellant inlet conditions.”
It is worth to remind that test from August 2015 and March 2016 both had similar objective: testing functionality and performance of new engine controller, which is crucial part of process of adopting RS-25 engines to SLS. Another part tested yesterday was ablative insulation of the nozzles designed to protect this important parts from heat generated by boosters and aft separation motors of SLS.
Yesterday’s test was divided into two phases. First which was planned to last for 277 s was covering generating 109% of power and second planned for 268 s to use 80% of engine’s power. But according to official statement by John C. Stennis Space Center, it was ended earlier than originally planned:
“Today at 5:57 p.m. (CST) RS-25 developmental engine number 0528 initiated a test firing. There was a minor issue with the test stand that triggered an early shutdown of the test. The test systems in place responded properly by shutting down the test in an orderly fashion.”
All parameters before interrupting were nominal and in general test was described as “successful in 80%”. Investigation on reasons of shutting down pointed that problem was generated by faulty connector between cable and one of accelerometers utilized by Advanced Health Management System (AHMS was designed in 2004 as cooperation of Boeing-Canoga Park and NASA-Marshall Space Flight Center to help in detecting engine anomalies during Space Shuttle missions and it is part of the RS-25). System decided to shut down engine basing on wrong data from affected accelerometer. In spite of problems with connector, new controller and insulation were working as it was predicted. RS-25 will be again tested in Stennis three times in 2016 and twice in 2017, but for the moment it seems that there are no major problems with adopting engines to new vehicle.
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