Hierarchical basalt metayarn for ergonomic protective space textiles

Space textiles must resist extreme cold, heat, and solar irradiation. Basalt fibers with extreme environmental resistance and low cost are the optimal materials for space colonization. However, they are too brittle to spin without damage for forming yarn and fabric, while flexible organic fibers that easily become yarn are not safe for space. This study invents a coaxial spiral wrapping spinning method to form a structure of full sheath-coverage, bidirectional hierarchical helix, and maximum core-sheath interfacial force in Metayarn by hierarchically wrapping fire-retardant sheath fibers onto double-helical basalt cores in a nondestructive and torque-free way. Thus, Metayarns are flexible, strong, and stable enough to be knitted into soft fabrics that defend against strong solar irradiation, extremely low and high temperatures (−200°C–300°C), and 1300°C flame. The ergonomic fabrics are cost-effective, dyeable, skin-friendly, and flexible, and they also have 421% stretchability and abrasion durability. Therefore, the fabrics are expected to serve as space suits, tents, and flags on the moon.