26 September 2001

The purpose of the Volatile Organic Analyzer is to monitor the internal atmosphere of the Station for the build up of toxic organic vapor compounds, and warn the astronaut crew and ground staff if these materials reach unacceptable levels where the health of the crew could be affected. The VOA uses a unique combination of absorbent trap pre-concentration, gas chromatography, and ion mobility spectrometry, to detect and quantify a programmed list of up to 300 possible volatile organic atmospheric pollutants, to levels of a few parts per billion. 

Design and development of the analyzer started in 1993 under contract to Wyle Life Sciences of Houston, Texas, who work closely with NASA on the Crew Health Care Systems of the station.  The first unit was delivered in 1996 and flew in the U.S. Space Shuttle in January 1998 to prove capability in a micro-gravity environment.  The second unit was delivered in August 1998, followed by the third in May 1999.  The second unit will operate for the first five years of the station life, to be replaced by the third unit, which will continue for the next five years.  The third unit is currently being used for astronaut and ground staff training.  A fourth backup unit, currently being fabricated at Graseby, is due for delivery in 2002. 

The ion mobility spectrometry (IMS) technology used in the Volatile Organic Analyzer is essentially the same as that used in Graseby's internationally known chemical warfare agent detection systems CAM, GID-2A and GID-3, as well as newer systems LCAD and MCAD coming into service with the UK Ministry of Defence.  The Built In Test Equipment in the VOA uses similar systems as those incorporated into these systems.  The success of these missions, and now the deployment of the Volatile Organic Analyzer on the International Space Station, demonstrate the flexibility, ruggedness and capability of the basic IMS technology and Built In Test Equipment.

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