Morphing Upper Torso: A Resizable and Adjustable EVA Torso Assembly
Jacobs, Shane E.
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Traditional Extravehicular Activity (EVA) spacesuits incorporate either hard or soft upper torso subassemblies as part of their architecture. In either case, these components are of a specific, fixed size and lack provisions to make significant sizing adjustments across the envelope of the torso. To address this limitation, this project furthered the Morphing Upper Torso (MUT) concept, an innovative pressure garment that allows for resizing of the torso and precise repositioning of the neck, scye and waist planes. This concept was initially developed several years prior, and analytical and experimental models of the full MUT design (in which the back hatch of a rear-entry torso is interconnected with the waist ring, helmet ring and two scye bearings) have been used to demonstrate the feasibility of this novel space suit concept. These previous efforts showed that the torso could be expanded to facilitate donning and doffing, and then contracted to match different wearer's body dimensions. Using the system of interconnected parallel manipulators, suit components can be accurately repositioned to different desired configurations. The project described herein furthered this novel concept, focusing on development of higher fidelity mockups and updated analytical tools and models. New higher fidelity mockups were designed and fabricated, incorporating Link-net as the restraint layer. Link-net is a unique “netting” material created and manufactured exclusively by David Clark. In this application, Link- net may provide advantages in the MUT architecture, due to its ability to self stow. When the MUT is reconfigured and resized to smaller dimensions than the restraint is designed, ideally the restraint material will stow underneath the resizable linkages, and will not buckle, dive in, or create hot spots, as is potentially the case with traditional woven fabrics utilized as a pressure garment restraint. Additionally, various sizing mechanisms were considered and design trades performed to choose a design that allows quick, reliable, mechanical adjustments of the linkages. Ideally the crewmember must be able to quickly make adjustments to the torso size after donning the suit. If it is a suitport-compatible suit, these adjustments must be made with the suit pressurized. Concepts that are optimal for both unpressurized resizing and pressurized resizing were designed. Finally, the analytical models have been updated in this project to reflect the current baseline exploration suit geometry. Using these updated analytical models and the higher fidelity mockups, analysis was performed to quantify a reasonable range of sizing adjustments for a wearable prototype, as well as outlining the sizing architecture to outfit the entire future crewmember population.