Scientists have devised a method for astronauts to create construction bricks from lunar soil quickly and efficiently.
One promising technique is microwave sintering, which involves exposing loose regolith to ultra-high-frequency microwaves. The naturally occurring metal particles in the regolith absorb the microwaves, converting them to thermal energy and causing the particles to fuse, forming solid bricks. This method is faster and more energy-efficient than other proposed techniques and does not require any additives. Unfortunately, previous attempts have yielded structurally flawed bricks unsuitable for practical use.
A breakthrough has been made by Dr. Hyu-Soung Shin and his team at the Korea Institute of Civil Engineering and Building Technology. They refined the microwave sintering process to create flawless, structurally sound bricks from a commercial regolith simulant called KLS-1.
Initially, the team used conventional microwave sintering, which resulted in bricks with internal cracks due to uneven heating. To solve this, they preheated the KLS-1 to 250 ºC (482 ºF) for about eight hours in a vacuum. Then, they placed the material in a multi-mode microwave sintering furnace at 1,080 °C (1,976 ºF) for 10 minutes. The final step involved cooling the bricks at room temperature for about 16 hours.
The resulting bricks were flawless, with uniform density, porosity, and compressive strength throughout. “The robust reproducibility and similarity in physical and mechanical properties validate the viability of microwave sintering in manufacturing large and uniform blocks suitable for application as construction materials on the Moon,” the scientists stated in their paper published in the Journal of Building Engineering.
Source: National Research Council of Science and Technology via EurekAlert