title: Evidence that the reactivity of the martian soil is due to superoxide ions.
abstract: The Viking Landers were unable to detect evidence of life on Mars but, instead, found a chemically reactive soil capable of decomposing organic molecules. This reactivity was attributed to the presence of one or more as-yet-unidentified inorganic superoxides or peroxides in the martian soil. Using electron paramagnetic resonance spectroscopy, we show that superoxide radical ions (O2-) form directly on Mars-analog mineral surfaces exposed to ultraviolet radiation under a simulated martian atmosphere. These oxygen radicals can explain the reactive nature of the soil and the apparent absence of organic material at the martian surface.
authors.affiliation: Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109, USA. Albert.Yen@jpl.nasa.gov
authors.forename: A S
authors.initials: AS
authors.lastname: Yen
authors.forename: S S
authors.initials: SS
authors.lastname: Kim
authors.forename: M H
authors.initials: MH
authors.lastname: Hecht
authors.forename: M S
authors.initials: MS
authors.lastname: Frant
authors.forename: B
authors.initials: B
authors.lastname: Murray
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry; D004578:Electron Spin Resonance Spectroscopy; D018559:Exobiology; D005118:Extraterrestrial Environment; D007477:Ions; D018535:Mars; D010100:Oxygen; D017680:Potassium Compounds / Q000737:chemistry; D012987:Soil; D013481:Superoxides / Q000032:analysis / Q000737:chemistry
chemical_list: D000538:Aluminum Silicates; D007477:Ions; D017680:Potassium Compounds; D012987:Soil; D013481:Superoxides; C016447:feldspar; D010100:Oxygen