3D PRINT

Revolutionary 3D-printing method dubbed Contour Crafting (CC), which made it possible to print a 2,500-square-foot building in less than a day on Earth in 2004.

In 2016 first prize in the NASA In-Situ Materials Challenge, for Selective Separation Sintering - a 3D-printing process that makes use of powder-like materials found on Mars and works in zero-gravity conditions.

Other approaches, like taking inflatables, also wouldn't work. Inflatables are made of polymeric material, like vinyl, so they won't survive long because the radiation on Mars is pretty intense. Radiation is the enemy of polymers, causing it to become weak and fragile.

In space, the environments are so hostile to humans that robotics will have to play a major role in preparing those places for the future of humanity.

Before we start building, what will the robots need to set up?
On Earth, there would be people to install the 3D printers, connect them to an energy line of some sort -- like a power grid. But in space, it all has to be done autonomously.So you'd need a source of power to be installed (by robots), like solar panels. And to use Martian materials, there has to be some kind of processing plant to create the materials. Then you need a way to transport materials to the machine and an automated machine has to print the material into the shape you want. Then basic infrastructure such as landing pads, roads, radiation protection walls and hangars can be built. Human habitats can follow next.

 IN-SITU RESOURCES UTILISATION 

(ISRU)

In situ resource utilization (ISRU) involves using materials encountered on Mars to produce materials needed. One idea for supporting a Mars habitat is to extract subterranean water, which, with sufficient power, could then be split into hydrogen and oxygen, with the intention of mixing the oxygen with nitrogen and argon for breathable air. The hydrogen can be combined with carbon dioxide to make plastics or methane for rocket fuel. Iron has also been suggested as a building material for 3D printed Mars habitats.

In the 2010s the idea of using in-situ water to build an ice shield for protection from radiation and temperature, etc. appeared in designs.

A material processing plant would use Mars resources to reduce reliance on Earth provided material.

To convert the whole of Mars into a habitat, increased air could come from vaporizing materials in the planet. In time lichen and moss might be established, and then eventually pine trees.

There is a theory to make rocket fuel on Mars, by the sabatier process. In this process hydrogen and carbon dioxide are used to make methane and water. In the next step, the water is split into hydrogen and oxygen, with the oxygen and methane being used for a Methane-Oxygen rocket engine, and the hydrogen could be re-used. This process requires a large input of energy, so an appropriate power source would be needed in addition to the reactants.