Sound on for the full effect! Operators conducted a successful test of RS-25 developmental engine No. 0525 – complete with a new flight controller unit – on the A-1 Test Stand this Tuesday, August 14. The hot fire was the first RS-25 test at Stennis since February, when operators powered the engine to its highest operating level ever. It also was the first test of developmental engine No. 0525 since August 2015. It marked the first in a series of nine scheduled tests on engine No. 0525 through the rest of the year and into 2019. Each will feature an RS-25 flight controller for use on an actual SLS mission, as well as testing engine components made with innovative manufacturing designed to reduce the cost of future engines. All test objectives were met during the hot fire. NASA is building the SLS rocket as the largest, most powerful space vehicle in history to return humans to deep space missions. The SLS rocket will launch crews of up to four astronauts aboard the Orion spacecraft t...