Mars X-House is a joint design and construction prototyping project undertaken collaboratively by SEArch+ and 3D-printing technology company Apis Cor, to envision architectural solutions employing large-scale additive manufacturing techniques in the context of a Mars mission.
Materials for use off Earth will be different than Earth construction as well and will be required to print, cure, and operate in the extreme of Martian temperatures and vacuum conditions. In-situ printing materials will need to be sourced, either mined from the soil or extracted from the atmosphere, and adapted for use in the printing process.
As the most obvious and abundant material on planetary surfaces, printing with regolith is a high priority. Printing with regolith, the Additive Construction with Mobile Emplacement (ACME) project is developing technology to build structures on planetary surfaces using in-situ resources.
The project focuses on the construction of both 2D (landing pads, roads, and structure foundations) and 3D (habitats, garages, radiation shelters, and other structures) infrastructure needs for planetary surface missions. The ACME project seeks to raise the technology readiness level (TRL) of two components needed for planetary surface habitation and exploration: 3D additive construction (e.g., contour crafting), and excavation and handling technologies (to effectively and continuously produce insitu feedstock).
Additionally, the ACME project supports the research and development of new materials for planetary surface construction, with the goal of reducing the amount of material to be launched from Earth. ACME is a joint venture between NASA’s Space Technology Mission Directorate Game Changing Development Program and the United States Army Corps of Engineers (USACE).
The USACE is interested in the additive construction technology as a means to build Army structures to enable field operations. The ACME project will help USACE minimize the number of people it takes to build a structure, minimize the amount of time it takes to build a structure, allow digital design and 3D printing of structures to resemble local buildings, and reduce the amount of material brought into the field and waste produced by the construction process. These goals are similar to those of NASA in the establishment of planetary surface mission infrastructure.
At the same time, regolith is understood to contain perchlorates that are toxic to humans. Every design effort has been made in to protect the human inhabitants from direct or indirect regolith exposure. In Mars X-House 1, the innermost layer to come in contact with the crew was a pre-integrated inflatable. In Mars X-House 2, regolith was lined with HDPE.
Basalt plays an important role in 3D printing on the Moon and Mars where it is abundant and easily accessible within the regolith. By heating basalt, basalt fibers can be made through a simple extrusion process. Basalt fibers are twice the strength of steel and only about one-third the weight.
On Earth, rebar and other extruded components made of basalt fiber are replacing many steel items typically used in construction.10 Pacific International Space Center for Exploration Systems (PISCES) has been working with Hawaiian basalt as a feedstock for ISRU (insitu resource utilization) to create novel materials for sustainable products on Earth and in space.
Hawaii’s basalt meets the specific chemical profile needed to manufacture CBF, a material similar to fiberglass and carbon-fiber. CBF products possess favorable characteristics including resistance to corrosion and heat, and high tensile strength. Globally, CBF manufacturing is valued at around $100 million and expected to double in the coming decade.
Plastics will be an additionally critical material to support construction in space. It would provide a non-porous boundary layer for air-tight structures, a layer of shielding from potentially toxic regolith, and also provide for many additional components of the architecture such as window, walls, doors, and floors.
Plastics such as HDPE will be produced using local ethylene resources on Mars. Methane fuel produced by the Sabatier reaction is expected to be a necessary component of future Martian missions derived from subsurface water and atmospheric carbon dioxide.
Methane may then be polymerized to form complex hydrocarbons via the Fischer Tropsch process, including plastics. While this is an energy intensive process, it is expected that Martian missions will need to be energy rich with nuclear power to ensure crew and mission safety.
A portion of polymer production may be generated by grinding, melting and re-using / re-cycling materials from the spent spacecraft. Additional plastics can be made using similar processes. Polycarbonate windows can also be made with in-situ materials.
Polycarbonate has high visual transmissivity offering the potential for true vision windows necessary to connect the crew to their new landscape.
Melodie Yashar, Co-Founder, Mars X-House Team / Project Leader, SEArch+ Space Exploration Architecture;
Christina Ciardullo, Co-Founder, Architect, SEArch+ Space Exploration Architecture;
Michael Morris, Co-Founder, Architect, SEArch+ Space Exploration Architecture;
Rebeccah Pailes-Friedman, Co-Founder, Industrial Designer, SEArch+ Space Exploration Architecture.
Dr. Robert Moses, NASA Langley Research Center;
Daniel Case, Ph.D. Candidate, Aerospace Engineering Sciences, University of Colorado – Boulder.