Feasibility of Standardized Ejecta Evaluation for Spacecraft Surface Materials

Although a large spacecraft such as the International Space Station and other artificial satellites are thriving in the space environment due to the remarkable progress in the space development sector, their collisions with space debris are a growing concern. To examine the impact proof performance of spacecraft to space debris, hypervelocity impact experiments using a two-stage light gas gun and so on are necessary. However, space debris impact experiments are conducted in different manners dependent on the countries and the facilities. Therefore direct comparisons of the experimental results among different facilities are often difficult from the same viewpoint. In this study, the authors aim at assessment of international standardization of the hypervelocity impact experiments procedure. Projectiles with a diameter of 1 mm were used to simulate space debris impacting a target at 5 km/s. Copper witness plates were used to catch the secondary debris, namely ejecta, generated during the experiments. The size distributions of diameter of craters made by ejecta were measured on the witness plates, and they are compared one another among a solar array coupon, CFRP honeycomb and Aluminum honeycomb.