You’ve seen these motors before—135 times before in fact. They’re the liquid-fueled muscle that helped launch all of the space shuttles. Now they’re being repurposed in a new rocket, the planned Space Launch System (SLS). That’s a prosaic name for an ambitious machine that could be the greatest booster the U.S. has built since the days of the legendary Saturn V. Will it fly? NASA’s current stop-start record with manned space projects does not portend great things. Nor does the fact that the launch date for the first manned flight keeps slipping. At the moment the space agency doesn’t plan for a meaningful test of the SLS with an unmanned Orion crew capsule atop until 2017. Still, this picture, which NASA touted on an Instagram post on Saturday, is impressive. The four engines on the SLS will use propellant at the rate of 1,500 gallons per second, emptying an average-sized swimming pool in one minute. When the rocket flies—if the rocket flies—that will produce a launch spectacle unlike anything we’ve seen since the 1970s.