Boron nitride nanotube fibers with over 1 GPa strength and 1000 °C stability for exceptional neutron shielding textiles.

Integrating boron nitride nanotubes (BNNTs) into robust macroscopic architectures for deep space radiation shielding remains a fundamental challenge. Here, we report continuous self-assembled all-nanotube (SAAN) fibers with an 80 wt% BNNT loading, combining tensile strength exceeding 1 GPa with extreme thermal stability from -196 to 1200 °C. These fibers originate from the thermodynamic co-assembly of BNNTs and carbon nanotubes (CNTs) into a lyotropic liquid crystalline mesophase. This shear-responsive dope enables cooperative reorientation and dense nanotube packing during wet-spinning. When assembled into macroscopic textiles, SAAN exhibits an exceptional thermal neutron attenuation coefficient of 2.85 mm-1. Furthermore, computational simulations indicate these lightweight textiles can effectively mitigate highly penetrating secondary thermal neutrons generated by Galactic Cosmic Ray (GCR) spallation. Demonstrating their seamless integration into commercial 2D flat and 3D tubular textile manufacturing processes, this nanomanufacturing approach provides a scalable and reliable strategy for space radiation shielding in both intravehicular (IVA) and extravehicular (EVA) activities.