The SLS five-segment Solid Rocket Motor undergoes a static test fire at the Orbital ATK facility in Promontory, Utah March 11, 2015. The beefed-up space shuttle solid rocket motor passed a two-minute test firing in Utah on Wednesday, a key milestone toward the debut flight of NASA's deep-space launcher in 2018, the U.S. space agency said. (Photo by Jim Urquhart/Reuters)
