Building on Mars

Abstract

Currently the possibilities of sending humans to Mars are being developed. This ambitious and exciting goal demands a broad range of new technologies, innovations and a fresh view on current challenges we are facing on Earth. This also applies to the field of Architectural and Building Technology.

To start with, the need for building a sustainable habitat is established, where sustainability is defined as being as independent as possible from Earth. Therefore, being sustainable on Mars is vital. This aspect is leading to the research by focusing on using in-situ resources (ISRU).

Based on this insight, the research question was formulated: Which in situ materials and forming techniques are suitable to create an outer shell for a sustainable habitat on Mars which protects the crew from the harsh Martian environment? The Martian habitat will have to protect the crew from, among others, radiation and the extreme temperatures (ranging from 20 °C to -153 °C).

Literature study shows that ice provides an excellent shield against radiation. Moreover, ice is widely present on Mars. Hence, a number of experiments were performed to test the feasibility of using ice as a building material. The results for all three tests were the same: the addition of sand or plastic does not upgrade the building properties of the ice. However, adding salt does improve the building properties. The outcome of the experiments indicates that up to 15 ppt of NaCl increases the compressive strength from an average of 1 MPa to 4 MPa. A higher percentage of sodium chloride does not influence the compressive strength. The experiments also indicated that the colder the testing environment (up to -70°C), the higher the compressive strength of the NaCl ice is. The warmer the environment (up to +25°C), the more ductile the NaCl ice behaves.

A further challenge to building a habitat on Mars is that it has to be built semi-remotely. This thesis singles out the use of robotic technology, which can perform all tasks necessary to build the habitat, ranging from mining the ice to assembling the building. A short analysis indicates that the use of additive manufacturing has great potential for the assembling of the building. In this thesis, preliminary studies and experiments have been conducted on additive manufacturing techniques for sodium chloride ice. The main outcome is that the ice structure has a greater overall strength due to the freezing of the ice layer by layer. This technique also enables the possibility of repair during the building phase as the water fills the possible cracks, and then expands upon freezing, creating a stronger structure.

Finally, a habitat has been designed to assess if the technological findings are useful and comply with the overall habitat requirements. The “Ice Hab” uses two different techniques of building with ice; one almost completely independent from Earth materials and another one with Earth technology for redundancy. Overall, the habitat design complies well with the requirements.