Extruded Clay-Based Regoliths for Construction on Mars, Phobos and NEAs

Research by Deep Space Industries and the University of Central Florida last year discovered an intriguing property of the carbonaceous asteroid simulants being developed. We noticed that simply wetting the material, mixing it thoroughly, and drying it (in vacuum or air) at ambient temperature causes it to bond into solid, very hard rock, and we could control the hardness by the amount of water mixed into it before drying. On Earth when making bricks from clay we need to fire them in a kiln at temperatures as high as 1300⁰C to make them hard. Apparently simple air or vacuum drying of these minerals can substitute for the kiln effectively, making it easily hard enough for construction in the space environment. Carbonaceous asteroids are not the only place in space where clayey regolith can be used for construction. Recently, scientists have shown that Mars has abundant clay deposits all over the globe. The minerals on Phobos appear similar to those in a certain type of carbonaceous asteroid including phyllosilicates (the type of minerals that include clays), so apparently Phobos may have abundant clay minerals, too. This suggests construction by low-temperature vacuum drying is possible on those bodies. It is not possible on the Moon, however, as there are no phyllosilicates on the Moon.