monitoring and control system comprised of several types of instruments. Such a system can be
included in an environmental control system, which actuates remediation of anomalous events.
RESULTS
Analysis of ENose monitoring data showed regular, periodic rise and fall of humidity. Occasional
releases of Freon 218 (Perfluoropropane), used in ISS cooling systems, were detected by ENose
and the Analyzing Interferometer for Ambient Air (ANITA) payload, another air quality
monitoring instrument. Formaldehyde, which is not detectable by any other instrument in the
US Lab, was frequently detected by ENose at low concentrations and may result from off-
gassing of polymeric seals or o-rings heated by operating equipment. Similarly, the presence of
methanol was detected by ENose but could not be correlated to any specific activities aboard.
ENose and ANITA detected the unexpected presence of sulfur hexafluoride (SF 6 ). Sulfur
hexafluoride was not on the JPL ENose target list of compounds, so it was reported as an
“unknown” event for the in-flight analysis. In postflight, based on sensor response modeling
inputs and experimental verification, it was determined these unknown events could be related
to SF 6 (Shevade 2010). Each detected event lasted from 20 to 100 minutes, which is consistent
with the air replacement time in the US Lab (Ryan 2009, 2010a).
PATENT(S)
Homer ML, Jan DL, Jewell AD, Kisor AK, Manatt KS, Manfreda AM, Ryan MA, Shevade AV, Taylor
C, Tran TA, Yen SS, Zhou H, inventors; System for detecting and estimating concentrations of
gas or liquid analytes. US patent 8,024,133. September 20, 2011.
PUBLICATION(S)
Ryan MA, Manatt KS, Gluck SE, et al. The JPL electronic nose: Monitoring air in the US lab on the
International Space Station. 2010 IEEE Sensors, Kona, HI; November 1-4, 2010.
Shevade AV, Ryan MA, Homer ML, et al. Characterization of unknown events observed by the
third generation JPL electronic nose using sensor response models. 40th International
Conference on Environmental Systems, Barcelona, Spain; July 11-15, 2010.
Kateb B, Ryan MA, Homer ML, et al. Sniffing out cancer using the JPL electronic nose: A pilot
study of a novel approach to detection and differentiation of brain cancer. NeuroImage.
2009;47(Supp 2):T5-T9. doi: 10.1016/j.neuroimage.2009.04.015.
Ryan MA, Manatt KS, Gluck SE, et al. Operation of third generation JPL electronic nose on the
International Space Station. SAE International Journal of Aerospace. 2009;2009-01-2522.
Shevade AV, Ryan MA, Homer ML, Kisor AK, Manatt KS, Lara LM. Monitoring pre-combustion
event markers by heating electrical wires. SAE International Journal of Aerospace. 2009; 2009-
01-2543.
This investigation is complete and all results are published.