Self-Propagating High-Temperature Synthesis Reactions for ISRU and ISFR Applications

Abstract

In the framework of ISRU (In-Situ Resource Utilization) and ISFR (In-Situ Fabrication and Repair) applications, a novel recently patented process based on the occurrence of Self-propagating High temperature Synthesis (SHS) reactions potentially exploitable for the in-situ fabrication of construction materials in Lunar and Martian environments is described in this work. Specifically, the SHS process involves thermite reactions type between Lunar or Martian regolith simulants and aluminum as reducing agent. To overcome the fact that the original content of ilmenite (FeTiO 3 ) and ferric oxide (Fe 2 O 3 ) on Moon and Mars soils, respectively, is not enough to make the SHS process possible, suitable amounts of these species have to be added to the starting mixtures.The dependence of the most important processing parameters, particularly the composition of the starting mixture, evacuation level, and gravity conditions, on SHS process behaviour and product characteristics is specifically examined for the case of Lunar regolith. All the obtained findings allows us to conclude that the optimized results obtained under terrestrial conditions are valid for in-situ applications in Lunar environment. In particular, parabolic flight experiments evidenced that neither SHS process dynamics nor product characteristics are significantly influenced in both Lunar and Martian systems when passing from Earth to low gravity conditions. Finally, the complete scheme involving all stages required for the fabrication of physical assets to be used as protection against solar rays, solar wind and meteoroids, etc., is reported.

Remarks on ISRU and ISFR Technologies for Manned Missions on Moon and Mars

“…The subsequent step, which is the core of the entire process, involves self-propagating high temperature combustion reactions taking place within the mixture resulting from the previous step. Details related to this process are reported in a recent paper [10]. Briefly, these reactions are characterized by the fact that, once ignited by an external energy source, they are able to self-propagate in the form of a combustion wave through the reacting mixture without requiring additional energy.…”