Akito MORIMITSU’s research while affiliated with Kyushu Institute of Technology and other places

The extreme heating environment during re-entry requires an efficient heat shield to protect a spacecraft. The current method of manufacturing a heat shield is labor intensive. The application of 3D printing can reduce cost and manufacturing time and improve the quality of a heat shield. A 3D printed carbon fiber/polyether ether ketone (CF/PEEK) composite was proposed as a heat shield material. The aim was to develop a heat shield and the structural member as a single structure while maintaining the necessary recession resistance. Test samples were exposed to thermal cycles and ultraviolet (UV) radiation environment. Subsequently, a tensile test was performed to evaluate the effect of thermal cycle and UV radiation on the mechanical properties. The sample’s recession performance and temperature behavior were evaluated using an arc heated wind tunnel. Exposure to thermal cycle and UV radiation have limited effect on the mechanical properties, recession behavior and temperature behavior of 3D CF/PEEK. Results from the arc heating test showed an expansion of the sample surface and better recession resistance than other existing ablator materials. Overall, 3D CF/PEEK has excellent recession resistance while maintaining mechanical properties when exposed to high temperature, thermal cycle and UV radiation.

When a spacecraft orbiting the earth enters the earth's atmosphere, it is exposed to an aerodynamic heating environment. The outer surface of the spacecraft has been covered with a carbonized ablator made of a CFRP to prevent this heat input from entering this spacecraft. From the research conducted so far, it has been found that a CFRTP has a specific strength and specific elasticity equivalent to that of a CFRP, and also has an excellent heat protection capability. In this study, we confirmed that a CFRTP does not deteriorate significantly by UV irradiation and thermal cycle and whether it could maintain the thermal protection capability.

Spacecraft employs heat shield as protection from high heat during reentry into Earth atmosphere. However, current heat shields are labor intensive to manufacture and cost prohibitive. Additive manufacturing technology or 3D printing allows rapid manufacturing, reduced cost and design flexibility. Hence, a new thermal protection system (TPS) was proposed to take advantage of 3D printing. The proposed system employs a 3D printed Carbon Fiber/Polyether Ether Ketone (CF/PEEK) composite as a thermal protection material and structure member. The durability of the TPS in LEO was evaluated by exposing test samples to different number of thermal cycles and ultraviolet (UV) radiation. Tensile testing was carried out to evaluate the tensile strength and Young’s modulus of the proposed TPS. The proposed TPS was also examined using an arc-heated wind tunnel to evaluate its thermal protection performance and thermal response. Tensile and are heating test results showed no significant degradation in mechanical properties and thermal protection performance after exposure to thermal cycle and UV radiation. In addition, the TPS achieved comparable thermal performance to existing ablators while maintaining good mechanical properties.