The Role of Chemical Sensors, Microfluidics, and Analytical Microsystems in Future Mars Exploration

The Viking Mars mission raised intriguing questions about Mars' surface chemistry. More than three decades later, an array of small electrochemical sensors included on the Phoenix Mars lander provided a key insight: Perchlorate, chlorine's most highly oxidized form, was present at surprisingly high concentrations in the regolith. This has implications for Mars' geochemistry, habitability, potential to support microbial life, and human exploration; as a strong oxidant, it might also help explain the destruction of organic compounds on the martian surface. Here, we examine the role of chemical sensors in the exploration of Mars and a critical allied enabling technology, microfluidics, from Phoenix to the present day and beyond. Enormous technological advances in microtechnologies, targeting terrestrial applications from everyday consumer electronics to wearable medical diagnostic devices, are just now beginning to be adapted and harnessed to support planetary science and discovery. These advances are poised to revolutionize how much can be learned using robust systems with unimaginably small requirements for size, weight, and power, making them compatible with small, potentially lower-cost delivery to the martian surface on hard landers, impactors, penetrators, and even rotorcraft.