If we built farms in space, they'd look nothing like the vast wheat fields of Kansas. But they just might look something like urban farms being used today—modular closed-loop hydroponic farms, actually. These compact, efficient grow houses could be the life-giving answer to keeping astronauts fed, a solution The Martian's Mark Watney could only dream of. The idea is less science fiction than you might think, too. Freight Farms, based in Boston, is trying to revolutionize the global food system with its Leafy Green Machines. These shipping containers filled with racks of planted crops, grow lights, and environmental control systems...