Combustion Joining of Regolith Tiles for the Construction of Launch and Landing Pads on the Moon and Mars
Combustion-based methods are attractive for space manufacturing because the use of chemical energy stored in reactants dramatically decreases the required external energy input. Recently, a sintering technique has been developed for converting lunar/Martian regolith into ceramic tiles, but it is unclear how to build a reliable launch/landing pad from these tiles with small amounts of energy and materials. Here the feasibility of joining regolith tiles using self-propagating high-temperature reactions between two metals powders is explored. Combustion of a 1:1 molar aluminum/nickel mixture placed in a gap between two tiles, made of JSC-1A lunar regolith simulant, was studied in an argon environment at 1 kPa pressure. Stable propagation of the combustion front was observed over the tested range of distances between the tiles, 2 – 8 mm. The front velocity was found to increase with increased spacing between the tiles. Joining of the tiles was achieved in several experiments and improvement with increasing the tile thickness was observed. Measurements of the thermophysical properties of the tiles, the reactive mixture, and the reaction product revealed that thermal diffusivity of the product is higher by two orders of magnitude than that of the initial mixture or the tiles. A model for steady propagation of the combustion wave over a condensed substance layer placed between two inert media was applied for analysis of the investigated system. Testing the model with different values from the obtained range of thermal diffusivities has resulted in reasonable agreement between the experimental and modeling dependencies. Both the experimental and modeling results indicate that the quenching distance in the investigated system is lower than 2 mm, which implies that a small amount of the reactive mixture would be required for sintering regolith tiles on the Moon.
Ferguson, Robert Edwin, "Combustion Joining of Regolith Tiles for the Construction of Launch and Landing Pads on the Moon and Mars" (2018). ETD Collection for University of Texas, El Paso. AAI10822664.