Long-term durability of tri-axial woven CFRP tube structure extended along the spin axis of spinning platforms for the SCOPE mission

This study investigates the strength and long-term durability of a spin-axis extensible rigid antenna element, made of tri-axial woven carbon fiber-reinforced polymer (CFRP), for a spinning spacecraft. Due to a slight deviation between the spin axis and antenna-extended axis with the spin, the antenna is subjected to centrifugal body force; the centrifugal force enhances the antenna deflection. A relationship between centrifugal force and antenna deflection is derived from beam theory. As the apparent material modulus decreases with time, the deflection increases simultaneously. The time dependence of mechanical properties of the tri-axial woven CFRP is hence examined by a creep test. The time-dependent failure criterion of the antenna is then examined using a flexural durability test. Based on the beam theory and experimental results, we examine the long-term reliability of applying the tri-axial woven CFRP to extensible rigid antenna for the spinning spacecraft, especially for SCOPE mission; it is verified that the current design tolerance for the mission assures certain durability for long-term usage.