Another nod to big progress made during 2015 building NASA's next generation rocket for missions to deep space! Pictured here, the first RS-25 engine test of the year for the Space Launch System (SLS), blazing into the night at John C. Stennis Space Center in Bay St. Louis, #Mississippi on January 9. The RS-25, formerly the space shuttle main engine, fired up for 500 seconds on the A-1 test stand at #Stennis, providing NASA engineers critical data on the engine controller unit and inlet pressure conditions. This was the first hot fire of an RS-25 engine since the end of space shuttle main engine testing in 2009. Four RS-25 engines will power SLS on future missions, including to an asteroid and Mars. Huge! Credit: NASA #NASA #progress #RS25 #slsfiredup #sls #nightshots #engineering #testfire #thisyear #space #exploration #spaceisrad #journeytomars