Thermo-Elastic Behavior of Pristine and Degraded Bistable Ultrathin Composite Booms in Low-Earth Orbits

Bistable ultra-thin composite booms capable of self-deploying from coiled stable configuration to extended shape offer significant potential for lightweight deployable space structures. This paper explores the thermo-elastic deformations of the deployed state of ultra-thin composite booms with circular arc cross-sections made from carbon fiber-reinforced epoxy laminates. FEM results show that the previous analytical model is not sufficient to describe the complex shape taken by the boom under uniform temperature variations, and that the boom needs to be sectioned into smaller sections for proper cylindrical fitting. Non-uniform temperature variations in the boom due to two radiation conditions (high and low) were obtained, and results show that the radius of the boom is modified by less than 0.3 mm, whereas the twisting angle is increased up to 1.2° at the tip of the boom. The temperature of the root of the boom was set to 0 °C, 20 °C and 40 °C with minimal impact on the resultant shape. Increasing the subtended angle from 66° to 180° revealed poorer cylindrical fits at the root and tip than in the center of the boom. The influence of mechanical bonding at the root of the boom is minimal and leads to a slight decrease in twisting angle. Finally, atomic oxygen exposure tests were conducted and extrapolated to long mission durations and show that the bistable booms reasonably maintain their profile after three years in low-earth orbits.