A booster for the most powerful rocket in the world, NASA Space Launch System (SLS) successfully fired up Tuesday for its second qualification ground test at Orbital ATK's test facilities in Promontory, Utah. This was the last full-scale test for the booster before SLS’s first uncrewed test flight with NASA’s Orion spacecraft in late 2018, a key milestone on the agency’s Journey to Mars. #JourneyToMars #SLSFiredUp #NASA ™nasa_marshall