Thermite reactions are strongly exothermic chemical reactions between a pure metal and a metal oxide, which causes the formation of a more stable metal oxide from the starting metal and a reduced metal from the starting metal oxide. The reaction needs an ignition temperature and can be used to refine a large array of metals at a relatively high purity. Depending on the chemical species involved, the ignition temperature can be different. An example of a reaction is involving iron oxide (Fe2O3) and aluminum (Al): Fe2O3 + 2Al → 2Fe + Al2O3, with aluminum oxide (Al2O3) and iron (Fe) resulting from the reaction. Nevertheless, the thermite reaction is not restricted to this application, as it can use as reactants other oxides (such as titanium oxides or silicon oxides). Being exothermic, the reaction also releases heat rapidly reaching temperatures as high as 2000°C. The specific energy of the reaction is > 4MJ/kg and higher energy can be achieved by changing the reducing and the oxidizing agents.
The idea proposed here is to study the potential of thermite reaction from chemical species mined from the lunar regolith with the aim to produce in-situ a wide range of pure metals and generate heat. As the specific energy released by the typical thermite reactions is ten times higher than that of Li-ion batteries, this reactor would represent an exceptional way of storing chemical energy. Also, as the energy is "trapped" in stable oxides, this storing system would not have the same demanding thermal requirements of batteries, making the concept very attractive for operations during lunar night or in permanent shadow regions.
The idea enables a wide array of ISRU metal production with a simplified pre-processing chain. Only one metal (i.e. Al) would need to be produced through a different ISRU production method. This enables for research to focus only on producing large quantities of a single reactant metal but enabling a large number of metals to be produced (ex: Ti, Si, Fe).
