Exploration of Planets Past, Present, and Future Habitability

With this task, we pursue our research in sedimentology related to the Mars Exploration Rover (MER) mission (mission data and terrestrial analogs), which has now entered its third extended mission and the interpretation of orbital imagery focusing on the basin deposits of the martian highlands. Our objective is to characterize and map potential life habitats from the ground and orbit. The current missions show that Mars was habitable in the past and possibly still habitable today in specific environments (e.g., the discovery of ice, salts, and potential nutrients at the Phoenix landing site, and orbiters observation of abundant subsurface ice and geologically recent volcanic activity that could have provided water and energy). There is, therefore, a possibility that life, if it ever appeared on Mars, might have survived the climatic transition of the Noachian/Hesperian period, 3.7-3.2 Gy ago up to the present, and could still be sheltered from hostile environmental surface conditions. In that perspective,the identification and characterization of underground habitats is becoming a priority in the search for life on Mars. As a result, within that task - and in addition to the tasks related to our participation to the MER team - we are now initiating a sub-task which objective will be the geological and morphological characterization of regions on Mars where caves could have formed and are possibly sheltering microbial life. The interest of caves is not only astrobiological. Human exploring planets will require shelters against hostile planetary environments as well as habitats. The idea that caves could be used as a foundation for human habitats on the Moon and Mars is being seriously considered by NASA. As a result, it is critical to develop the tools and skills to detect them. This new task will support this effort and is relevant to both NASA’s human exploration and astrobiology science objectives.

From Habitability to Life

Building upon the results of the MER mission, and of our theoretical, experimental, and field work in high-altitude lakes, we bring the focus of this new proposal to the transition from habitability to life. The MER mission has demonstrated that Mars was habitable for life as we know it (in its microbial form) in its early geological history. But habitability does not equate to life, and critical questions have yet to be answered. A sample of those are:

* Did the transition happen?
* What was the biological potential of Mars?
* What were the environments where life could have had the mostly likely chance to develop and, perhaps, survive?
* What kind of extreme conditions did life face?
* What types of adaptation and survival tools and skills could life have used?
* If Mars developed life, can we still find its geological, mineralogical, or biological signatures today, whether it is extinct or extant?