A Volatile Organic Analyzer for Space Station: Description and Evaluation of a Gas Chromatography/Ion Mobility Spectrometer

Compared with previous U.S. space flight missions, the risk of atmospheric contamination on board Space Station Freedom (SSF) is substantially increased because of the large number of on-board experiments, long-term storage of chemical wastes, and the release of offgas products into the closed environment over the station's 30-year lifetime. Degraded air quality aboard SSF could affect crew health and safety as well as mission success. This paper describes the development of technologies for an on-board Volatile Organic Analyzer (VOA), an essential component of the Environmental Heath System (EHS) air-quality monitoring strategy that warns the crew and ground personnel if volatile compounds exceed safe exposure limits.

Achieving the performance requirements established for the VOA within power and weight constraints led to a novel approach in which gas chromatography (GC) was combined with ion-mobility spectrometry (IMS). Both GC and IMS have been used successfully for aspects of environmental monitoring and analysis; however, only a few research-oriented efforts have been undertaken to interface the two technologies. This paper describes the development of a gas chromatograph/ion-mobility spectrometer (GC/IMS) system to be used to detect volatile organic compounds on SSF. The sample concentrator, high temperature IMS cell, and GC-IMS interface will be emphasized. Analysis of data collected during initial evaluations of the GC/IMS will be presented. Mobility spectra, chromatograms of mixtures, and concentration studies will be highlighted. In addition, future applications of this system will be discussed.