Understanding spacesuit interaction using a wearable proximity sensing system for suit fit optimization

Abstract

There is currently no quantitative method of measuring space suit fit for astronauts after they have put on the spacesuit. The primary concern for spacesuit fit is the hard upper torso (HUT), which is composed of a rigid fiberglass shell with metal scye bearing joints where other suit components attach. There is a concern with how much shoulder mobility the HUT is providing for astronauts. As astronauts perform tasks in the suit, there are contact and strain injuries that come from the repeated shoulder joint movements. When the distance between the shoulder joint and the metal scye bearing joint is too small, there is higher likelihood for musculoskeletal injuries. The purpose of this research investigates the use of a wearable proximity sensor to incorporate in the spacesuit to measure distance between the shoulder joint and metal scye bearing joint of the HUT. Two electromagnetic resonant spiral sensors were created and used for proximity detection where the investigation of proximity response to a metal was used. These wearable proximity sensors were tested in various environments to resemble environments inside the spacesuit. The first environment tested two sensor designs in proximity to only metal and then expanded to test the proximity sensors resting on a cooling garment that is in the spacesuit. Next testing environment included multiple proximity sensors of the same design in proximity to a curved metal sheet to more resemble the scye bearing joint. Results indicate that addition of the cooling garment reduces accuracy, although still has reliable accuracy of less than one millimeter. Consequently, adding more proximity sensors for the same environment proves feasible with future scenarios to still be tested. This wearable proximity sensor system establishes quantitative measurements that will aid in optimization of spacesuit fit. The use of this system during fitting, donning, or training during various movements will be able to provide vital assessment of spacesuit fit to avoid shoulder joint injury.