Extravehicular activity suit penetration resistance

Abstract

The penetration resistance to hypervelocity impact (HVI) has been determined based on test and analysis for the extravehicular mobility unit (EMU) space suit used by astronauts to perform extravehicular activities (EVA). The suit is broadly divided into two categories: soft goods and hard goods depending on their flexibility. In the soft good category, HVI tests were conducted on samples representative of the arms, legs, briefs, gloves, glove gauntlet, and overlap regions. Hard goods examined include the hard upper torso (HUT), portable life support system (PLSS), and helmet. Ballistic limit equations have been developed that define the particle size on the perforation threshold of the suit bladder as a function of impact conditions (velocity, angle, and density). Penetration equations have also been developed for predicting particle sizes causing uncontrollable leaks (i.e., with bladder hole sizes exceeding 4 mm diameter). These equations are necessary to perform orbital debris and meteoroid risk assessments for EVAs.