Hydrogen Sensor for the ISS Oxygen Generation Assembly

This paper provides a description of the hydrogen sensor used on the Oxygen Generation Assembly (OGA), to be operated on the International Space Station (ISS). The sensor is being designed by Makel Engineering, Inc. (MEI) to monitor the oxygen outlet for the presence of hydrogen. The signal outputs are utilized for system shutdown in the event that the hydrogen concentration exceeds the specified shutdown limit. The hydrogen sensor is currently in the development phase, with 3 development units on test. Preliminary results are positive and have allowed for testing of several specific design requirements, such as sensor performance with nitrogen exposure and varied dew point level. This paper also provides a status of development testing and of progress on the flight design.