2012 Annual Science Report
VPL at University of Washington Reporting | SEP 2011 – AUG 2012
Understanding the Early Mars Environment
There is no liquid water on modern Mars, although there is plenty of solid ice. Observations from orbiting satellites and rovers on the ground suggest that liquid water may have flowed over the Martian surface in the distant past. VPL researchers are studying the geologic record of Mars for clues of past water, and investigating climate and chemical conditions under which water would be stable. Team members examined different climate feedbacks and geochemical processes that could have warmed the early Mars. Some members are also active members of the MSL science team.
VPL team members have continued extensive work on the climate, atmospheric chemistry, and geochemistry of Mars. The work includes theoretical calculations, analog field work, and direct robotic fieldwork on the surface of Mars.
Pan Conrad is the deputy PI of the Sample Analysis at Mars instrument which is currently in Gale Crater on the surface of Mars, and her efforts this year have shifted from field work to tactical operations for MSL, anticipating the first results from SAM.
David Catling has been involved in three studies of geochemistry of Mars as informed by orbiting satellites and rovers. These papers span the geochemical spectrum, address the formation of interior layered deposits (sulfates), carbonates, and clays. Meg Smith, David Catling, and Kevin Zahnle have added chlorine and bromine to a Mars photochemical model, discussed results in 3 conference poster sessions, and are preparing a publication on perchlorate formation on Mars.
Warming Early Mars remains a theoretical challenge, and two new climate feedback mechanism proposed in recent years have been applied to early Mars. In 2011, Pierrehumbert and Gaidos suggested a H2/CO2 greenhouse could warm exoplanets, and Ramses Ramirez, Michael Zugger and James Kasting have explored the conditions under which a H2/CO2 greenhouse could warm early Early Mars in a submission to Nature Geosciences. In 2010, Rosing et al (including VPL team member Norm Sleep) proposed that a reduced albedo on early Earth might help solve the faint young sun paradox. Jacob Haqq-Misra has shown in a paper in Astronomy and Astrophysics that this does not work for early Mars.
VPL members were active on the conference and field circuit. Mark Claire attended the 3rd International Conference on Mars Analogs, where he presented results from his 2011 NAI/APS Lewis and Clark Fellowship trip to the Atacama desert, Chile. In addition he collected samples from Southern Morocco to add to his growing database of desert salts. Kevin Zahnle and David Catling attended the 3rd International Conference on Early Mars, giving presentations on erosion rates and their climate implications, constraints on atmospheric evolution from Martian meteorites, and on impact ejecta into oceanic versus volcanic crust. David and Kevin also co-wrote book chapters on early Mars to be published in 2013 by Cambridge University Press.
PROJECT INVESTIGATORS:Mark Claire
PROJECT MEMBERS:David Catling
David Des Marais
RELATED OBJECTIVES:Objective 1.1
Formation and evolution of habitable planets.