Experimental Investigation of Planetary Atmospheres

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Exploration of Mars addresses the most profound questions concerning habitability for life, either in the distant past or the present. The findings from each Mars exploration mission provide pieces of the puzzle and the most crucial advancements so far concern water. There is evidence for flowing liquid water on Mars in the distant past and it is understood that much of that water has escaped to space over the history of the planet. The rate at which the water escapes the atmosphere is dependent on the transport pathways from the surface to the upper atmosphere. Clouds in the atmosphere of Mars are composed of ice crystals that grow large enough to precipitate to the surface. This is a mechanism for dehydrating the air as it ascends to the upper atmosphere, confining water to lower altitudes. The clouds and precipitation are a significant factor in the rate at which water is lost from the planet and thus also in the history of water on Mars. One of the objectives of the research program is to investigate the role of clouds and precipitation in dehydrating air as it ascends through the atmosphere of Mars. This is being carried out using measurements of clouds and water vapour from the NOMAD instrument on the European Space Agency Trace Gas Orbiter mission that is currently in orbit at Mars. These measurements are being interpreted using a computer simulation model to trace the path of air parcels through the atmosphere of Mars.     Another objective of the research program concerns the exchange of water between the surface and the atmosphere on Mars. This has implications for understanding the origin of the vast amount of water ice below the surface of Mars. An important discovery during the NASA Phoenix Mars mission was the identification of perchlorate salt in the surface material. Perchlorate salt is of great interest for studies of water on Mars due to its ability to absorb water vapour from the atmosphere into a liquid solution with a freezing point that is as low as -67 degrees Celsius. It is possible that liquid water occurs on the surface of Mars. This has intriguing biological implications since such a liquid brine solution could potentially provide a habitable environment for living organisms. A new instrument is being developed to investigate this process in the laboratory with the conditions on the surface of Mars being recreated within an environmental chamber. The long-term goal is to carry out the investigation on the surface of Mars with a miniaturized version of the instrument on a landed spacecraft.     Trained students will gain skills in optical technologies and analysis methods that are of widespread use in Canadian science and industry. Contribution of an instrument for a future Mars mission will be a benefit to Canada as a multidisciplinary group of academics from various Canadian universities would compose the science team, and the Canadian space engineering industry would construct the space qualified instrument.