4:00 PM - 5:00 PM
Questions about the potential for life to exist on Mars hinge on the planet’s climate and on the history of the atmosphere and volatiles. Answers depend on the availability of liquid water and of elements that are important to climate and life (such as C, H, O, N, and so on). I will summarize the current state of knowledge about the history of the Martian climate and the associated uncertainties. This will lead into a discussion of the upcoming Mars Atmosphere and Volatile EvolutioN (MAVEN) mission that will determine the role that loss of gases from the atmosphere to space has played in the history of the Martian environment. MAVEN is the first mission devoted to understanding the nature of the Mars upper atmosphere, its interactions with the Sun and the solar wind, and the amount of gases that have been lost to space. Although the measurements that will be made are of the upper atmosphere, MAVEN is a geological and astrobiological mission -- its objective is to understand the history of the climate and atmosphere, as fundamental boundary conditions on the history of the surface and surface processes and on the habitability of Mars by microbes. MAVEN launches in November, 2013, has a ten-month cruise to Mars, and then a one-year primary science mission. It will arrive at Mars at the time of the declining phase in the solar cycle, when solar storms are likely to be most intense and most abundant. Eight science instruments will measure the composition and structure of the upper atmosphere, the rates of escape to space at present, the solar energetic inputs that drive the processes controlling structure and escape, and characteristics that will allow us to determine the net loss to space throughout Martian history.