Sensors for spacecraft cabin environment monitoring

It is very necessary, in manned spaceflight, to ensure that essential variables, including concentrations of oxygen, carbon dioxide, water vapour and volatile organic contaminants, are maintained within acceptable limits. Furthermore, the purity of drinking water, etc. must at all times be assured. Moreover, for lengthy voyages, the proliferation of bacteria and other microorganisms may need to be monitored. Here we present a platform approach to these problems based on multiplexed optical fibres sensitized to the different analytes by coating them with thin-film capture layers of bionanomaterial composites. Both amplitude and interference measurement modes are described, as well as a photoactivated amplitude measurement mode offering further sensitivity enhancement. It is a great and novel advantage that the same technology, and hence the same data processing and diagnostics procedures, can be used over a vast range of analytes in both gaseous and liquid media.