Engineers and students grapple with 3-D printing a habitable structure on Mars

We are in the midst of a "Mars moment." This fall, the Matt Damon film, "The Martian," a story about a stranded astronaut who must learn to survive on Mars, grossed a whopping $55 million at the box office in its opening weekend. The same week, scientists breathlessly revealed the discovery of liquid water on Mars, raising the possibility that life might yet exist there.