A system to sense near-surface atmospheric gases of possible biological origin on Mars

This paper describes a robot system that is equipped with an open path spectrometer proposed to look for signs of indigenous life on Mars. The system was developed to search large areas around a landing site for gases that have a possible biological origin. The rationale for the system, instrumentation and measurements are described. Data is presented from field studies conducted at Mars analog sites in Arkansas. Unique problems addressed include 1) localization of gas sources with a minimal set of equipment; 2) handling both strong (at short measurement distances) and weak (at long distances) laser light signals, with a variable sunlight background; 3) optimal photo detector placement, which depends on measurement distance; 4) managing measurements in wind; and 5) measurements of low concentrations of gases.