There's a fundamental stumbling block when it comes to building a base on Mars, and that's getting all the building materials there in the first place. No problem, though, because NASA is busy engineering space bugs that will turn the crap on the planet into building materials to help make the hostile planet habitable.
New Scientist reports that NASA is using synthetic biology to create an army of microbes that could be easily shipped to the planet: they weigh next to nothing, and take up hardly any space. Once on the ground, though, they would multiply as they fed on materials available to them, and in the process produce the building blocks required to create a Mars base. New Scientist explains:
[A] team, led by recent Brown graduate André Burnier and advised by [Lynn ] Rothschild [from Ames Research centre in Moffett Field, California], has... come up with a way to supply human settlers on Mars with bricks and mortar. They began with a bacterium called Sporosarcina pasteurii, which, unusually, breaks down urea - the principle waste product in urine - and excretes ammonium. This makes the local environment alkaline enough for calcium carbonate cements to form... The idea is that the waste produced by astronauts could feed the microbes. The microbes, in turn, would help cement together fine rocky material on a planet's surface to create bricks.
In other words, astronaut pee would be turned into a binding agent which, when combined with Mars dust, could create bricks. The same binding agent could be used to stick them together, too. It's not just limited to bricks'n'mortar, though: the team think they can provide microbial colonies to provide oil, plastics or even fuel from crap found on the red planet.
However you look at it, they're amazing promises, which would be difficult to believe were it not for the fact that they're clearly already making good on their claims. When it comes to inhabiting Mars, then, it looks like we'll be packing light -- just remember your toothbrush and a big box of microbes. [New Scientist]