Autonomous robot 3D printers like this could help build homes for us on other planets

MIT’s new 3D-printer doesn’t need much direction. It takes the form of a pair of robotic arms — one hydraulic, one electric — mounted on tank-like treads. Steer it into place, and it can create a 12-foot-high dome in less than 14 hours, using building materials (in this case, insulating foam) it carries in a mini-trailer. A dome like this might not look like much to you or I, but the robot’s creators say it’s a big step towards 3D-printed whole buildings.The s