Covalently Fused Nanofiber Aerogels With Exceptional Mechanical Robustness and Thermal Insulation for Deployable Space Systems

ABSTRACT Nanofibrous aerogels exhibit an ultralow bulk density, making them highly desirable for lightweight aerospace structures. Nevertheless, these materials are often hampered by inherent physical brittleness, leading to severe structural failure under complex mechanical loads. To address this challenge, we developed a hybrid aerogel featuring core‐shell inter‐fiber junctions covalently fused via siloxane bonds, fabricated by in‐situ vapor‐phase polymerization of poly(vinylsilsesquioxane) (PVSQ) on a continuous and crosslinked native bacterial cellulose (BC) network. This unique architecture endows the aerogel (BC‐PVSQ) with outstanding mechanical adaptability and toughness, including >99% compressibility, bending resilience (curvature > 20 mm −1 ), robust tensile strength, and structural integrity over 10,000 shearing cycles. Significantly, it maintains low density (16.1 mg cm −3 ) and thermal conductivity (27.0 ± 0.2 mW m −1 K −1 ). As a proof of concept, we demonstrate the practical potential of the material for space‐deployable drag‐augmentation deorbiting spheres, enabling reversible folding compaction and reliable deployment, and for flexible habitat insulation, where it shows superior thermal insulation performance relative to conventional aerospace insulation materials under simulated Martian atmospheric conditions. This work successfully resolves the longstanding trade‐off between mechanical robustness and thermal insulation, laying a multifunctional technological foundation for next‐generation lightweight deployable systems designed for space environments.