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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.

Spacecraft modules that are last purged with clean air several months before they are entered by humans on orbit require careful management. The crew must not be exposed to harmful concentrations of air pollutants when they first enter. The magnitude of the pollution the crew will encounter depends on the volume of the module, the length of time since the last clean-air purge or scrub, the inherent offgassing rate of the materials in the module, the interior temperature of the module while offgassing occurs, and the system leak rate. The time of the last module purge or scrub can be several months before crew entry, so it is essential that the offgassing rate within the module be measured over a suitable interval of time to estimate pollution levels with confidence. Air samples were taken from the STS-74 Russian Docking Module, the STS-79 Spacehab, and the ISS Node 1 prior to launch to predict pollution levels at crew first entry.

A volatile organic analyzer (VOA), developed by Graseby Dynamics, Ltd. under contract to the Johnson Space Center Toxicology Laboratory, is the core instrument for trace contaminant monitoring on the International Space Station (ISS). The VOA will allow trace amounts of target compounds to be analyzed in real time so that ISS air quality can be assessed in nominal and contingency situations. Recent events on Mir have underscored the need for real-time analysis of air quality so that the crew can respond promptly during off-nominal conditions. The VOA, which is based on gas chromatography/ion mobility spectrometry, is the first spacecraft instrument to be used for such a complex task. Consequently, a risk mitigation experiment (VOA/RME) was flown to assess the performance and engineering aspects of the VOA. This paper is a review of VOA/RME results from the STS-81 and STS-89 flights and their implications for the ISS VOA design and operations.