Microsensor analyses for trace targets over extended times in a simulated Martian environment

Abstract

We have studied the performance of a chemical microsensor array in a simulated Martian environment, which involved a carbon dioxide-rich background with low oxygen content (0.15 %) at low pressure and temperature to mimic the conditions at the Martian surface. Gas-phase target analytes (methane, ethane, hydrogen and sulfur dioxide) in complex ternary mixtures at concentrations of 200 nmol/mol and below were presented to the microsensor array under these conditions. The array featured individual metal oxide sensing elements on microhotplate platforms. We will review our operational approach for this extraterrestrial environment and report on the capabilities of the microsensor for detecting the target analytes. In particular, we will emphasize the application of Partial Least Squares-Discriminant Analysis (PLS-DA) models for the detection of the analytes, and discuss how the microsensor array performed over extended periods of operation (up to 3 weeks between training and test exposures).