Hypervelocity impact damage equations for Kapton multi-layered insulation and Teflon second-surface mirrors

We report the results of recent hypervelocity impact tests into aluminised Kapton multi-layered insulation (MLI) and silverised Teflon second-surface mirrors (SSM), by means of an electrothermal gun. A comparison between the MLI and SSM impact perforations and those in pure Kapton and Teflon reveal large dimensional discrepancies. An empirical equation is provided for MLI which, though restricted in its range of applicability, can be applied in the extraction of impactor characteristics from perforation hole diameters.