Evolution of 3D printing processes and applications will have significant importance to near-term and long-term planetary space program initiatives. Long-term Martian missions will require large amount of supplies to be transported to Mars. In-situ Resource Utilization and 3D printing will reduce the interplanetary material transportation needs and thereby will contribute to more efficient Mars colonization. 
In recent days, houses have been already 3D printed on Earth. Infrastructure and time required for printing makes this method very unique. The composition of Martian soil enables it to be used as a 3D printing material. Martian atmospheric composition and presence of water allows production of 3D printing binder material to be produced on the surface. The elements of Matian soil that are essential for 3D printing are Hydrogen, Oxygen, Silicon, Iron and Carbon. The binder material to be used is Polyethylene. Polyethylene is also a good radiation shielding element. Availability of Carbon Dioxide in the atmosphere and water in the soil will be important for production of Polyethylene.
It begins with deployment of central module containing all the equipment including small 3D printer.A small 3D printer will print the structural elements of large scale 3D printer. Large scale 3D printing will take place around the central module.
All essential robotics and power sources will be delivered to Mars prior to the initial settlement. Power source will be Kilowatt. Once 3D printing of habitats is finished, they will bemade Human-rated to ensure the habitability of 3D printed domes. Due to change of the physical state of material for 3D printer, there is a possibility of outgassing from a solid printed structure.
Polychlorotrifluoroethylene (PCTFE) material which has a very low permeability to CO2, O2 and N2.The spray of PCTFE will be used inside 3D printed habitat structures to minimize possible outgassing.
Multiple 3D printed domes will serve different functionalities: habitation, science and medical labs and green house. These are the essential functions that will be needed during initial settlement on Mars.