Enabling 3D Printing of Space-Durable High-Performance Polymers: Low Earth Orbit Exposure.

The rapid expansion of the new space sector requires advanced materials capable of supporting reliable, cost-effective, and customizable space technologies. Additive manufacturing enables the fabrication of lightweight structures with complex geometries; however, conventional polymers generally degrade under the harsh space environment, including atomic oxygen (AO) exposure, ultraviolet and ionizing radiation, and large thermal fluctuations. To overcome these limitations, hybrid photopolymers based on cyanate ester (CE) and extended bismaleimide (E-BMI) are developed for digital light processing (DLP) 3D printing. Incorporation of UV-curable polyhedral oligomeric silsesquioxane (POSS) enables the in situ formation of a protective SiO2 passivation layer during AO exposure, improving durability in low-Earth orbit (LEO). Printed specimens were exposed aboard the International Space Station for 145 days as part of the MISSE-17 mission. Samples containing POSS exhibited up to 78% lower AO-induced erosion compared with POSS-free controls. Surface analysis confirmed the formation of SiO2-rich protective layers. Printing orientation was found to influence AO reactivity and surface degradation, highlighting the importance of geometry-dependent optimization. Mechanical and thermomechanical properties remained stable after flight exposure, indicating strong resistance to the LEO environment. These results demonstrated the suitability of CE/E-BMI-POSS hybrid materials for durable, high-resolution DLP-printed components intended for long-term operation in LEO.