Researchers in the School of Physics and AMBER, the SFI Centre for Advanced Materials and BioEngineering Research have published a paper in Small which demonstrates the effectiveness of advanced materials, in this instance carbon nanotubes, in enabling the fabrication of structural materials in extraterrestrial environments.

Future space missions will need to fabricate building materials on the moon or Mars from local soil or regolith (Lunar or Marian soil). This research demonstrates that carbon nanotubes can be used as a binder to convert fine sand as well as lunar and Martian regolith simulants into solid “bricks” with excellent mechanical properties. This paves the way for nanotubes to be used to fabricate structural materials in extraterrestrial environments.

Professor Jonathan Coleman who leads the research project said: “We have demonstrated a process that allows small quantities of carbon nanotubes, to be used to convert powders such as Lunar or Martian soil into building materials that can monitor their own structural health. The resultant bricks are of relatively low density but have impressive mechanical properties. Our strongest bricks display compressive strength of 100 MPa, approaching that of granite. They can be produced near room temperature, minimising the energy required to make them. These composites may be a key component in the building of the first semi-permanent bases on the moon, Mars or beyond.”

Constructing a semi-permanent base on the moon or Mars will require maximal use of materials found in-situ and minimisation of materials and equipment transported from Earth. This will mean a heavy reliance of regolith and water, supplemented by small quantities of additives fabricated on Earth. This research shows that silicon dioxide-based powders, as well as Lunar and Martian regolith simulants, can be fabricated into building materials near room temperature using only a few percent of carbon nanotubes as a binder. These materials have compressive strength and toughness higher than the best terrestrial concretes. They are electrically conductive and display an extremely large piezoresistive response, allowing these composites to be used as internal sensors to monitor the structural health of extra-terrestrial buildings.