Published on Materials Today on 2 February 2015
Researchers from Washington State University have created dense ceramics from a lunar dust simulant – they say that it could be used for structural applications on the moon
Lunar bases have always been a dream of science fiction, but with NASA’s Orion program, the Moon has come back into focus. If all goes well, Luna will have a key role to play – a staging post for the next generation of human space exploration missions. In order to do this, we will need some sort of permanent settlement structure on the surface, and work from Washington State University may have found the perfect (and local) building block – moondust!
Engineers Gualtieri and Bandyopadhyay [DOI: 10.1016/j.matlet.2014.11.153] used standard powder sintering techniques to produce a series of dense ceramic materials, which then underwent mechanical tests. Samples of actual lunar dust are rare, so the team used JSC-1A; the lunar regolith simulant used the world over. Produced by NASA and ORBITECH, it is very similar to actual lunar dust, in terms of both its chemical and mechanical properties and the average particle size distributions found on Luna. Particle sizes in the simulant range from very fine (27 µm) to coarse < 5 mm. Previous papers had hypothesized that a lunar ceramic’s porosity could be controlled by changing the initial powder particle size. To test this, the powder was sieved so that two different ceramics could be produced – one using the smallest particles (27 – 212 µm) and one with the largest particles. Sintering was carried out in a standard commercial furnace.
Analysis of the microstructure of the final samples showed that the JSC-1A particles did, in fact, sinter together and create a dense ceramic structure. However, there were some differences – those ceramics produced with the coarse powder produced high porosity sintered samples, while those made with fine powder were more dense, with far fewer, smaller pores. Compression tests on the final sintered samples showed that the mechanical properties of the fine-powder ceramic outperformed that of the large-particle ceramic by a factor of two. However, their hardness was found to be comparable to commercial-grade zirconia, suggesting that they could find use in use in structural applications.
The process of sieving powder, pressing and heating it is widely used, and the team remains confident that it could be feasibly employed in a lunar environment. So, we may yet see bricks of moondust!
Materials Letters (2015) DOI: 10.1016/j.matlet.2014.11.153