Normal and 45º Hypervelocity Impact Tests to Evaluate Spacecraft Material Ejecta

Until September 2012 and the adoption of ISO11227, no standardized test procedure existed to evaluate ejecta from spacecraft material. Kyushu Institute of Technology is carrying out hypervelocity impact tests to contribute to the standard database enrichment and standard improvement. This paper reports 1) a review of the normal impact tests results, 2) the first results for oblique impact tests, and 3) the future studies to be carried out. Ejecta size distribution for normal impact tests showed that ejecta tend to impact in smaller concentric circle as their size increases, whereas ejecta smaller than 75 mum seem to impact uniformly the witness plate. Preliminary results of oblique impact tests showed that ejecta form a trail along the central axis of the witness plate. The authors also observed that the impact of the biggest fragments, 100 ~ 750 mum, were concentrated in two distinct areas showing that these fragments were cone-ejected at about 50o.