Mars and 3D Building Printing
This company used cement, but also a mixture of recycled materials, but the recycled materials were used because they are cheap. However, the Martian soil is even cheaper, as in free, and already in a form that's easy to collect: "The dust that covers the surface of Mars is fine like talcum powder. Beneath the layer of dust, the Martian crust consists mostly of volcanic basalt rock. The soil of Mars also holds nutrients such as sodium, potassium, chloride and magnesium."  And free materials with handy construction properties is just what is needed for such a giant 3D printer as seen in the video above. Scientists have already considered this possibility, and even with some pre-plans (video) , but somehow seeing what this Chinese contractor is doing makes the prospect much more real, indeed fully viable, since it's already actually being done.
Although the contractor above built a giant, custom 3D printer for his needs, the sales trend of mass manufacturing of 3D printers is already going up at a geometric rate, as this graph shows :
The reason for such a sales increase is that people are figuring out how to apply these printers to various tasks at hand. Once the abilities of these "additive manufacturing" machines are understood, printers of scale will be built for large tasks, especially for buildings, since the process from CAD software to 3D printer is becoming so smooth, and since the cost factor is greatly reduced. Such a positive cost curve is driving a huge growth in industry as this (clickable) graph shows :
I remember reading about the colonization of Mars in a book some years ago, whereby lots of prepackaged buildings and supplies were dropped on Mars months before astronauts ever arrived. At the time the book was written, it made perfect sense, though it depended on an Earth-tethered space elevator being already in place to cheaply move the materials into low earth orbit, which gets around the huge fuel problem for getting things into space at all. Sadly, it appears that a space elevator is not practical even if, against all odds, we could build one. But 3D printers solve this problem, since much of the infrastructure can be built on site.
My belief is that a series of small 3D printers will be sent to Mars, and these small printers will build the actual large printers necessary (w/ video) to produce the final infrastructure product. Yes, it is indeed possible to print 3D printers with a 3D printer, which is the full manufacturing circle -- a device can replicate itself. For example, The RepRap is an open source printer that does just that, and there's no reason that even larger 3D printers on Mars couldn't do the same, printing all the parts that make themselves up, and then having robots assemble the parts .
[image] "3D printers print ten houses in 24 hours" YouTube (Accessed 7/4/2014)
 "What is Mars Made Of?" Space.com (Accessed 7/4/2014).
 "3D Printing Houses on Mars" FutureScape on scienceChannel.com (Accessed 7/4/2014)
 "Solid Print" The Economist 4/21/2012 (Accessed 7/4/2014)
 "The Rise of 3D Printing in Manufacturing" Distribute: Tributes Blog for Industrial Distributors 4/7/2013 (Accessed 7/4/2014)