Scientists are working on a type of lunar cement that can be formed using moon dust and the waste products from human habitation – the urine of astronauts in particular. In experiments, researcher Dr. Anna-Lena Kjøniksen (Østfold University College in Halden, Norway) has developed a cement from urea and particles that simulate lunar soil (in preparation for a future Moon landing). Th simulated substance was silica and aluminum oxide powder.
The idea is that astronauts could create concrete and cement, which can then be 3-D printed on the Moon, in order to create materials in a variety of shapes which can then be used to build lunar dwellings.
In terms of where urine comes in, to make cement this requires a large quantity of water. Given that water is scarce on the Moon and not easy to haul into space, the astronauts themselves (along with any future Moon inhabitants) could be the source of a chemical that decreases the amount of water required – urea.
When cement in made on Earth, it is common to add chemicals that decrease the amount of water required. These chemicals are termed super-plasticizers (or ‘high range water reducers’). These are synthetic polymers which decrease the water level needed for cement manufacturing.
Trials showed that the use of urea (from urine) in combination with the materials to simulate Moon dust was successful and create a cement like material that can be used with additive manufacturing processes.
The research has been published in the Journal of Cleaner Production. The research paper is headed: ” Utilization of urea as an accessible superplasticizer on the moon for lunar geopolymer mixtures.”
In related news, the GENeco Bio-Bus that moves around the city of Bristol in the U.K. runs from human waste. The bus fleet is powered by toilet wastes, together with discarded food, in the form of a gas that is used to powers the vehicle, according to Science News. The gas is created by bacteria, where the human waste is processed in the form of sludge, in a device called an anaerobic digester.