Establishment of Ejecta Evaluation During Hypervelocity Impact of Large Structures in Geostationary Orbit

Abstract Currently, there is a significant amount of space debris in Earth's orbit. This debris orbits at extremely high speeds, posing a major threat to spacecraft. There is concern that debris tends to accumulate in geostationary orbit, where many satellites operate, potentially impacting their operations. In this study, we prepared aluminum and CFRP (carbon fiber reinforced plastics) targets and conducted hypervelocity impact experiments to evaluate the ejecta. For the aluminum targets, impact tests were conducted at speeds of approximately 1, 3, and 5 km/s. For the CFRP targets, both aluminum spheres and glass spheres were impacted at approximately 1 km/s. Additionally, two CFRP sheets were placed side by side to simulate a honeycomb structure. As a result, in experiments using aluminum as a target, it was possible to evaluate the amount of ejecta generated at each speed and thickness. In tests using CFRP, when aluminum spheres were used as projectiles, the number of ejecta craters decreased with increased target thickness. When glass spheres were used as projectiles, the brittle nature of the material led to more fragmentation compared to ductile materials. Consequently, while the number of ejecta increased with thicker targets, the size of the ejecta could be reduced.