The pathfinder is a microcosm of SLS itself—and not just because it’s a physical stand-in. There are multiple contractors and subcontractors associated with NASA’s Marshall Space Flight Center in Huntsville, Alabama. Pieces of the pathfinder ship to a central location for assembly. And the pathfinder will visit three NASA centers in the southern U.S.

I mapped out the journey of the core stage pathfinder using StoryMap, a free tool from Northwestern University’s Knight Lab (thanks to the Houston Chronicle's Adrift series by Eric Berger for the idea). Click through and you’ll see just how complex this one, seemingly minor aspect of the SLS program is. It’s helpful when visualizing how individual NASA projects impact local economies, and why politicians are eager to keep these programs in their districts.

The pathfinder project costs about $8.6 million, according to NASA representatives. It’s part of a larger, five-year engineering contract awarded by Marshall to three companies back in 2013, worth a potential $350 million.