Investigation on offgas monitoring system for the manned space systems

The offgas monitoring system under development consists of COTS (Commercial Off The Shelf) based offgas sensors and the controllers for those sensors. The offgas sensors are constant voltage electrolysis sensors, which can detect HF, CO, NO₂, HCN and HCI, and a semiconductor sensor that can sense odors. Some improvements such as immobilization of electrolyte in the constant voltage electrolysis sensors and installation of a pump to generate the airflow alternative to convection, has been made on the developed system in order to adapt the microgravity environment on orbit. This system can detect not only the unexpected toxic gases caused by the abnormal elevated temperature condition but also a fire event in very early stage, which cannot be detected by the smoke detector used on ISS, the International Space Station.