Fragments analysis of an hypervelocity impact experiment on a solar array

A large fraction of spacecraft external surfaces or appendages often consists of solar arrays, which can be subjected to space debris impacts as in the case of the Sentinel 1 A event of August 2016. Therefore, it is of interest to understand how solar arrays respond to hypervelocity impacts and to investigate the generated fragments population. In this context, the University of Padova performed an impact experiment on a solar array consisting in a composite sandwich panel, coated with a Kapton layer, and provided with solar cells: a nylon cylinder of 0.039 g collided with the solar panel at a velocity of 4.86 km/s with an impact angle of 45 deg, detaching a solar cell and damaging the panel structure. More than 4500 fragments larger than 0.2 mm were collected and classified after the impact. In this paper the impact experiment is described and the fragments analysis is presented in terms of size and shape distributions; a comparison with a test on a composite sandwich panel shows that the distributions are strongly affected by material and manufacturing choices, in particular regarding the fragments generated by delamination.