NASA/America Makes launched a 3D printing challenge to come up with the best design for a 3D printed habitat on Mars. There seems to be growing interest in this sector because of the major economic advantages of 3D printing in remote locations.
The winners were can be found here and below I have reproduced my entry.
3D – Printed Habitat Challenge
About Team Ulmo has background in 3D printing technologies, founder of 3D printing company that helps businesses integrate new 3D printing technology. Designer of new carbon fiber manufacturing method via 3D printing. B.A. in economics from University of Colorado, Colorado Springs.
Summary A self contained 3D printer that can be easily landed, can autonomously construct a habitable structure, aide in habitation and research and provides an innovative architectural method using existing technology.
Machine The machine called, “Ulmo” is dome-like with a flat removable bottom. The top of the dome is threaded and circular to support the body of a 9 meter screw column with a 50 cm diameter. A robotic arm is supported at the base of the screw column. The base of the screw column is drill shaped for the purpose of embedding itself into the terrain. The screw column is partly hollow to accommodate the storage of the robotic arm. The robotic arm has a triangular shaped extruder head that is used to extrude and form the construction material.
Structure The structure is hexagonal with triangular features, the purpose of which is to provide a strong bond between foundation and walls. The foundation is 10 cm thick. the bottom portion of the Ulmo detaches upon landing and is therefore not carried upward with Z movement. It is intended to create a solid circular core around the screw column and provide foundation anchoring. The building terminates in the dome of the Ulmo. As the building is constructed from the bottom up, the Ulmo turns along the screw column which moves the dome of the Ulmo up (or down) as required. Arches built from native material provide support for the dome and add structural strength to the building. The shell or walls of the building are 10 cm thick, the building has two shells or two exterior lines on both the exterior wall and the interior wall. The internal structure of the wall is a honeycomb with a hollow central channel that is used at a later stage for filling the walls with a water mixture. The purpose of the water mixture is to provide radiation shield for the inhabitants. The diameter of the structure measured from interior wall to interior wall is 12 meters. The walls are 110 cm thick.
Innovative approach Recognizing that certain critical components will need to be imported from earth and that size and weight of the object being sent from earth to mars are limits of our economics and technology. The design makes the building the 3D printer. Gathering of material is done by drilling down rather than by collecting surface materials for three major reasons: 1)It requires a much simpler and therefore more robust mechanism. (pump vs movable harvesting robot) 2) Drilling down can provide a source of water, useful for both habitation and the proposed radiation shielding. 3) The chance of finding something scientifically interesting is much higher.
Testing is also easy on earth because of the variety of materials the Ulmo is designed to process.
The 3D printing mechanism Colloquially called fused filament fabrication or FFF is a deceptively simple mechanism for 3D printing an object. I assume the reader is familiar with the method so I will just highlight why this is the preferred method for building a habitat on Mars. The method is extremely robust. Almost any material can be used. We are already building FFF machines that print in concrete. The critical components are limited to the extruder. The extruder governs the pressure of the material, allowing 0G and low atmosphere printing and applies force to the material it is spreading which enables it to bond to the previous layers. In the case of the Ulmo, the robotic arm is fed via pump from the end of the screw column. Although immobile, it provides stability and robustness. The other major advantage of this design is that it can be ‘planted’ via orbital insertion.
Interior The central shaft will have four low walls that radiate out from the center to form rooms for the four astronauts, providing a modicum of personal space. Kitchen space, gym, workspace showers, toilet are placed on the exterior walls. The central ring in between the living quarters and various rooms provides access everywhere and doubles as a track for running. The overhead arches provide a warm human feeling to the inhabitants while the dome they support provides a point for storing sensitive, hard to move and install, equipment such as the ECLSS, radio or sensor.
Building Site Lobate Debris Aprons in the Mid-Northern Latitudes is a suitable location because of its interesting scientific value and and access to ice.
Inspiration The building was inspired by a study available materials. The Martian “soil” shares similarities to types of volcanic ash. Some of the masters of this building material were the Romans who combined it with quicklime to produce a type of concrete that while being weaker than modern concrete has shown to be more durable in harsh conditions. It was often combined with incongruous materials like loose stones, recycled bricks or even other parts of buildings. It is natural to adopt the building features of this time such as domes and high arches as they provided the needed strength with the available materials.