Onset of petalling in a thin spacecraft wall perforated by an orbital debris particle

Abstract

All spacecraft in low earth orbit are subject to hypervelocity impacts by meteoroids and orbital debris. Recent studies have shown that the nature of a spacecraft wall perforation can range from a flat hole with a jagged edge (i.e. a so-called cookie-cutter hole) to a hole accompanied by bulging, cracking and petalling. If a cracking event were to occur on-orbit, unstable crack growth could develop, which could lead to an unzipping of an impacted pressurized spacecraft module. It is therefore imperative to be able to determine whether or not a spacecraft wall perforation will be accompanied by either petalling or cracking. This paper presents the results of a study whose objective was to develop an empirical model that could be used to determine whether a spacecraft wall perforation would be in the form of a petalled hole or a cookie-cutter hole. The model consists of a petalling limit function that predicts the onset of petalling in terms of impact conditions and spacecraft wall system geometry. The model is used to show that the perforation of a spacecraft wall with an enhanced shield will always be accompanied by petalling and cracking, while the perforations of a Whipple-type spacecraft wall may or may not be petalled and cracked, depending on impact conditions.