Results from the air quality monitor (gas chromatograph-differential mobility spectrometer) experiment on board the international space station

Abstract

The Air Quality Monitor (AQM), formerly called the microAnalyzer™, showed great promise in ground testing and preflight preparation to replace the aging Volatile Organic Analyzer (VOA) on the International Space Station (ISS). The atmosphere in the ISS is mostly scrubbed and recirculated (a partially closed environmental system), and for this reason the measurement of volatile organic compounds (VOCs) in its atmosphere is an important function to protect crew health and safety. Evaluation of the AQM in ground testing was impressive, but the unique environment of ISS required a thorough in-situ vetting of the capability. In May 2009, the first two AQMs arrived on ISS as an experiment to evaluate their performance and assess methods and crew procedures. In total, three AQMs have been operated aboard ISS spanning almost 3 years. After the first year of operation, the decision was made to build operational AQM units as a replacement for VOA, which was removed from ISS in August 2009. This paper presents the AQM data used to make the decision to build an operational version of the hardware. As an experiment of new hardware it was expected that some performance issues would arise, but it was also deemed necessary that solutions to these problems would not substantially change the form, function, or cost of the operational version. The identified issues and their solutions that related directly to the AQM’s analytical performance during the first year of the experiment are discussed briefly with the focus on how these changes are expected to improve the performance of the operational version. Recent AQM data from ISS will be presented to illustrate how some changes in software and methods are already improving the AQM’s analytical performance.