Get ready! The largest, most powerful rocket booster built for flight will fire up for a major ground test Tuesday at Orbital ATK's test facilities in Promontory, Utah. This is the last, full-scale qualification test for the booster before the first, uncrewed flight of our new rocket, the Space Launch System, with the Orion spacecraft in 2018. More: http://go.nasa.gov/295WXD9 #JourneyToMars | NASA - National Aeronautics and Space Administration