The Technology Demonstration of the Third Generation JPL Electronic Nose on the International Space Station

Introduction

The JPL Electronic Nose (Ryan, 1997, 1998, 2000, 2001, 2004a, 2004b) is an event monitor designed and built for near real time air quality monitoring in crew habitat aboard the space shuttle/space station. This is an array–based sensing system which is designed to run continuously and to monitor for the presence of selected chemical species in the air at parts-per-million (ppm) to parts-per-billion (ppb) concentration ranges. The Jet Propulsion Laboratory (JPL) is a federally funded research and development facility managed by the California Institute of Technology for the National Aeronautics and Space Administration (NASA) (http://www.jpl.nasa.gov/). Its mission is to enable space exploration for the benefit of humankind by developing robotic spacecraft and instruments.

There have been three phases of development of the JPL Electronic Nose. In the first phase, arrays of sensors were investigated and a device capable of detecting, analyzing, and quantifying ten analytes at the 1-hour Spacecraft Maximum Allowable Concentration (SMAC) (Toxicology Group, 1999) was developed. This device was tested successfully for six days on Space Shuttle flight STS-95 in 1998 (Ryan, 2004a). In the second phase, the ENose was miniaturized and the capabilities were significantly expanded to include 21 analytes and detection at varying humidity and temperature. This device, the Second Generation ENose, was tested extensively on the ground, and was demonstrated to be able to detect, identify, and quantify the 21 analytes at or below their 24-hour SMACs. The third phase of development was designed to monitor spacecraft cabin air quality in near real-time. A technology demonstration of the Third Generation JPL ENose aboard the International Space Station (ISS) was performed in 2008-09. Analytes included ammonia, mercury and sulfur dioxide, and eight organic compounds, which represent common classes of organic compounds. Analytes and targeted detection concentrations are shown in Table 1.