NASA is thinking about putting astronauts on the first flight of its future giant rocket

NASA is mulling over the idea of putting astronauts on the first flight of the Space Launch System (SLS) — the giant heavy-lift rocket the space agency is building to take people to Mars someday. Currently, NASA is hoping to fly the SLS for the first time in fall of 2018, and the original plan was for that mission to be uncrewed. But a new memo sent out to NASA employees this morning shows that the agency will start investigating the possibility of making the debut flight of SLS, called EM