Recycling carbon-fiber-reinforced plastics (CFRPs) is crucial for sustainable material utilization, particularly in aerospace applications, where large quantities of prepreg waste are generated. This study investigated the mechanical properties of highly oriented recycled CFRP (rCFRP) molded using vacuum-assisted resin transfer molding (VaRTM), wet-layup, and traditional RTM methods. Recycled carbon fibers (rCFs) obtained via solvolysis and pyrolysis were processed into nonwoven preforms to ensure fiber alignment through carding. The influence of molding methods, fiber recycling techniques, and fiber orientation on mechanical performance was examined through tensile tests, fiber volume fraction (Vf) analysis, and scanning electron microscopy observations. The results indicated that the solvolysis-recycled rCF exhibited superior interfacial adhesion with the resin, leading to a higher tensile strength and stiffness, particularly in the RTM process, where a high Vf was achieved. Wet-layup molding effectively reduced the void content owing to autoclave curing, maintaining stable properties even with pyrolyzed rCF. VaRTM, while enabling vacuum-assisted resin infusion, exhibited a higher void content, limiting improvements in mechanical performance. This study highlights that tailoring the molding method according to the desired performance, such as increasing stiffness potential by enhancing Vf in RTM or improving tensile strength by improving fiber–matrix adhesion in wet-layup molding, is critical for optimizing rCFRP properties, providing important insights into sustainable CFRP recycling and high-performance material design.

This study investigated the damage caused by sub-millimeter debris impact on the structures of unmanned spacecraft owing to the increase in the amount of sub-millimeter debris in the low earth orbit. Panel structures are mainly made of honeycomb sandwich panels, and the chassis of electronic devices are mounted on the panel. Because damage to the electronic device strongly influences the mission success of a spacecraft, determining the damage to the chassis wall behind the structure panel is important in debris protection design. Hypervelocity impact experiments were performed on the sets of an aluminum honeycomb sandwich panel and an aluminum alloy plate. The aluminum alloy plate was installed behind the honeycomb sandwich panel, without a standoff distance. In the experiments, sub- millimeter steel spheres (diameters of 0.15-1.0 mm) were accelerated up to 6 km/s by a two-stage light gas gun. Impact angles were varied from 0° to 30°. The depths of craters on the aluminum alloy plate were measured after the impact. A crater depth equation that applies when impact angles are less than 16.1° was calculated empirically.