Continued Development of Non-intrusive, Distributed Gas Sensing Technology for Advanced Spacesuits

Spacesuit development and ground-based testing require sensing and analytical instrumentation for characterizing and validating prototypes. While miniature thermosensors measure reliably at low cost, and can be incorporated all around spacesuit prototypes, incorporating gas sensors at locations of interest inside a spacesuit has been a significant challenge – in particular for human subject tests – because of the size and cost of available instrumentation. The first system has been developed for non-intrusive gas sensing in space suit prototypes based on flexible sensitive patches positioned inside the prototypes and interrogated by optical fibers routed outside the suit, taking advantage of the transparent materials of the suit prototypes. In this paper, the most recent results are presented of the development and analytical validation of sensor patches for carbon dioxide, humidity, oxygen, and ammonia. Studies conducted to evaluate the sensor analytical characteristics and the calibration requirements are presented. Operation of the sensors using Mark III-like helmet parts is presented. Data collected to show the system flexibility for choosing multiple sensing points, fitting the sensor elements into the spacesuit, and cost effectively relocating the sensor elements as desired, is discussed.