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Common Helmet Design for Launch, Entry, & Abort and EVA Activities – A Discussion on the Design and Selection Process of Helmets for Future Manned Flight
Abstract:
Effective helmet performance is a critical component to achieving safe and efficient missions along the entire timeline; from launch and entry events to operations in a micro-gravity environment to exploration of a planetary surface, the helmet system is the capstone of the pressurized space suit assembly. Each phase of a mission requires uncompromising protection in the form of a robust pressure vessel and adequate protection from impact, both interior and exterior, all while remaining relatively comfortable and providing excellent visual interaction with the environment. Historically there have been large voids between these critical characteristics with the primary focus concerning the pressure vessel first and impact protection and crew comfort second.
ILC Dover, NASA-JSC, Gentex Corporation, and Hamilton Sundstrand formed an Integrated Product Team (IPT) and conducted a NASA funded study to research and evaluate new concepts in helmet design. This study conceptualized and planned the development of a common helmet system that will deliver a new generation of space flight helmets that incorporate three key features: a helmet system that is IVA/EVA capable, offers excellent acceleration and impact protection, and provides an openable visor feature. This study also discussed the methodology, design, and testing for impact protection in helmets
Throughout the course of the study, these three features guided the designs at both the component and system levels. Several families of helmet designs were evaluated and the best, most mature system is one that incorporates an elliptical, hemispherical bubble. It can easily be configured for a waist-entry soft upper torso (SUT) or a rear-entry SUT. The helmet can utilize an adaptive element that allows the helmet to be installed to either SUT; depending on the ultimate suit architecture it could be made to fit both without additional hardware. A benefit of this geometry is the degree of freedom allowed in selecting the openable visor configuration. A rear-mounted hinge and strut arrangement allows for a very large & comfortable opening, while another solution replaces half of the hemispherical bubble with soft-goods to reduce system mass and provide a smaller operational volume. The following discussion is a synopsis of the design factors, approaches, and philosophies that the IPT underwent during the course of the study.