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The Volatile organic analyzer (VOA) has been operated on the International Space Station (ISS) throughout 2002, but only periodically due to software interface problems. This instrument provides near real-time data on the concentration of target volatile organic contaminants in the spacecraft atmosphere. During 2002, a plan to validate the VOA operation on orbit was implemented using an operational scheme to circumvent the software issues. This plan encompassed simultaneous VOA sample runs and collection of archival air samples in grab sample containers (GSC). Agreement between the results from GSC and VOA samples is needed to validate the VOA for operational use. This paper will present the VOA validation data acquired through November 2002.

The Volatile Organic Analyzer (VOA) was launched to the International Space Station (ISS) aboard STS-105 in August 2001. This instrument has provided the first near real-time data on the concentrations of trace contaminants in a spacecraft atmosphere. The VOA data will be used to assess air quality on ISS in nominal and contingency situations. Until the VOA presence on ISS, archival samples that were analyzed weeks if not months after the flight were the only means to obtain spacecraft air quality data on volatile organic compounds (VOCs). Especially in contingency situations, real-time data is important to help direct crew response and measure the effectiveness of decontamination efforts. The development and certification of the VOA has been chronicled in past ICES papers. This paper will discuss the preparation of the VOA for ISS operations. Also, examples of VOA data acquired during flight will be presented to demonstrate the value of the instrument in assessing the ISS environment.

The Toxicology Laboratory at Johnson Space Center (JSC) had provided the combustion products analyzer (CPA) since the early 1990s to monitor the spacecraft atmosphere in real time if a thermodegradation event occurred aboard the Shuttle. However, as the operation of the International Space Station (ISS) grew near, an improved CPA was sought that would include a carbon monoxide sensor that did not have a cross-sensitivity to hydrogen. The Compound Specific Analyzer-Combustion Products (CSA-CP) was developed for use on the International Space Station (ISS). The CSA-CP measures three hazardous gases, carbon monoxide, hydrogen cyanide, and hydrogen chloride, as well as oxygen. The levels of these compounds in the atmosphere following a thermodegradation event serve as markers to determine air quality. The first permanent ISS crew performed the CSA-CP checkout operations and collected baseline data shortly after arrival aboard the ISS in December 2000.

The crew of flight 2A.1 that manned the International Space Station (ISS) assembly mission (STS-96) in May 1999 experienced symptoms that they attributed to poor air quality while working in the ISS modules. Some of these symptoms suggested that an accumulation of carbon dioxide (CO2) in the work area could have contributed to temporary health impacts on the crew. Currently, a fixed-position CO2 monitor in the FGB is the only means of measuring this air contaminant aboard ISS. As a result of this incident, NASA directed the Toxicology Laboratory at Johnson Space Center (JSC) to deliver a portable CO2 monitor for the next ISS assembly mission (STS-101). The Toxicology Laboratory developed performance requirements for a CO2 monitor and surveyed available CO2 monitoring technologies. The selected portable CO2 monitor uses nondispersive infrared spectroscopy for detection. This paper describes this instrument, its operation, and presents the results from ground-based performance testing.

Experiences during the Shuttle and NASA/Mir programs illustrated the need for a real-time volatile organic analyzer (VOA) to assess the impact of air quality disruptions on the International Space Station (ISS). Toward this end, a joint development by the Toxicology Laboratory at Johnson Space Center and Graseby Dynamics (Watford, UK) produced a 1st generation VOA that has been delivered and is ready for the first 5 years of ISS operation. Criteria for the selection of the 1st generation VOA included minimizing the size, weight, and power consumption while maintaining analytical performance. Consequently, a VOA system based upon gas chromatography/ion mobility spectrometry (GC/IMS) was selected in the mid-90’s. A smaller, less resource-intensive device than the 1st generation VOA will be needed as NASA looks beyond ISS operations. During the past three years, efforts to reduce the size of ion mobility spectrometers have been pursued.