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Electron Spin Resonance (ESR) detection of active oxygen species and organic phases in Martian soilsThe presence of active oxygen species (O(-), O2(-), O3(-)) and other strong oxidants (Fe2O3 and Fe3O4) was invoked in interpretations of the Viking biological experiments and a model was also suggested for Martian surface chemistry. The non-biological interpretations of the biological results gain futher support as no organic compounds were detected in the Viking pyrolysis-gas chromatography mass spectrometer (GCSM) experiments at concentrations as low as 10 ppb. Electron spin resonance (ESR) measures the absorption of microwaves by a paramagnetic and/or ferromagnetic center in the presence of an external field. In many instances, ESR has the advantage of detailed submicroscopic identification of the transient species and/or unstable reaction intermediates in their environments. Since the higly active oxygen species (O(-), O2(-), O3(-), and R-O-O(-)) are all paramagnetic in nature, they can be readily detected in native form by the ESR method. Active oxygen species likely to occur in the Martian surface samples were detected by ESR in UV-irradiated samples containing MgO. A miniaturized ESR spectrometer system can be developed for the Mars Rover Sample Return Mission. The instrument can perform the following in situ Martian samples analyses: detection of active oxygen species; characterization of Martian surface chemistry and photooxidation processes; and searching for organic compounds in the form of free radicals preserved in subsoils, and detection of microfossils with Martian carbonate sediments.
Document ID
19890016997
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Tsay, Fun-Dow
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Kim, Soon Sam
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Liang, Ranty H.
(Jet Propulsion Lab., California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
September 6, 2013
Publication Date
March 1, 1989
Publication Information
Publication: NASA, Ames Research Center, Exobiology and Future Mars Missions
Subject Category
Space Biology
Accession Number
89N26368
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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