Mars atmospheric oxidant sensor (MAOS): an in-situ heterogeneous chemistry analysis

We describe a chemometric array sensor, the Mars atmospheric oxidant sensor (MAOS, pronounced “mouse”) that is designed to measure the oxidation rate of thin films on the martian surface. We select films that are sensitive to particular types of oxidants, that represent key elements in the martian soil, or that emulate prebiotic materials. Concern that naturally arising martian oxidants may have destroyed evidence of ancient life on Mars was raised by the Viking mission in the 1970s. The possibility that oxidants may limit the viability of biological habitats is particularly timely in the light of recent suggestions of contemporary flowing water on Mars. By controlling the temperature of the films, as well as their exposure to dust and ultraviolet light, MAOS will discriminate among leading hypotheses for oxidant production. MAOS weighs 55 g, fits in a 6×7×2 cm3 envelope, and used 250 mW power. Much of the enabling technology was developed for the MOx experiment, lost on the Russian Mars ’96 mission.