NASA resumes RS-25 testing

NASA resumed RS-25 rocket engine testing for its new Space Launch System (SLS) rocket with a hot fire test today on the A-1 Test Stand at Stennis Space Center (SSC). It marked the first RS-25 test of the year at SSC, continuing a series with developmental engine No. 0525 that began last August. The test again featured a flight controller to be used on an SLS mission and marked the third time since last February that NASA has powered its RS-25 engine up to 113 percent of original thrust. NASA is testing RS-25 engines to help power the SLS rocket, being built to send humans deeper into space than ever before. Four RS-25 engines, firing simultaneously, will produce 2 million pounds of combined thrust during SLS launch and ascent. RS-25 engines for initial missions are former space shuttle engines, designed to provide a power level categorized as 100 percent thrust. For SLS, engineers are modifying RS-25 engines to provide up to 111 percent of original thrust. Testing at 113 percent at SSC demonstrates a margin of safety for operating the engine at the higher thrust. A key component of the modifications is the new flight controller, which acts as the "brain" to help control engine operation and facilitate communication between the engine and SLS rocket. Aerojet Rocketdyne has received delivery of 18 new controllers from subcontractor Honeywell International Inc., 16 to be used on the first four SLS missions, one qualification unit and one engine spare. NASA has been testing the new controllers at SSC since March 2017. The RS-25 hot fire also continued testing of two engine components – a 3D-printed pogo accumulator to dampen pressure oscillations that can cause flight instability and a main combustion chamber fabricated using a hot isostatic pressure (HIP) bonding technique. The test today was the first since mid-December, when a test was terminated early due to an observed anomaly.(Source: NASA/SSC, 02/13/19)