Effect of Fe-Ni metals on ablation, cavity formation, and recrystallization in laser processing of chondrite meteorite

Laser processing is an effective method for cutting extraterrestrial rocks, making it potentially useful for space mining. By comparing laser processing of terrestrial basalt and the Hammadah al Hamra 346 (HaH 346) chondrite meteorite, we investigated the influence of iron-nickel (Fe-Ni) metals on laser-induced melting, cavity formation, and recrystallization. Experimental results revealed that the presence of Fe-Ni metals significantly reduces the depth of laser-induced cavities in HaH 346 meteorite while increasing their width, as the melting metal strongly absorbs laser energy. X-ray computed tomography results demonstrated that the laser-induced cavities in the HaH 346 meteorite are much shallower than those in basalt. Microstructural analysis indicated that Fe-Ni metals in HaH 346 recrystallize into ellipsoidal crystal formations, while silicates form complex and nest-like structures. Furthermore, the temperature of Fe-Ni metal during laser irradiation is significantly lower than that of silicate and mixed zones. Due to the vacuum environment of space, Fe-Ni metals are widely present in planetary rocks. Our study highlights the potential of laser cutting for future space mining and the key differences between laser cutting on Earth and in space.