Life in the Atacama: Science and Technology Pathways to the Robotic Search for Life on Mars

Introduction: Whether life ever existed on Mars or survived profound climate changes is unknown. However, all recent missions have returned evidence that thin films of liquid water or ground ice are present under current conditions [1]. Their presence supports the hypothesis that the martian subsurface could have provided a suitable refuge to life as surface conditions became hostile. Life might still be present, its habitat distribution possibly following residual water. Yet, despite large aquifers predicted at depth and surface ice in the polar regions, most of Mars remains extremely arid. The distribution of residual water/ice is likely to be heterogeneous, and to follow global to local factors, e.g., climate, geology, topography. Accessing deep aquifers can be performed by deep drilling [2] but requires significant infrastructure and may only have limited to no mobility, constraining the number of sites visited per mission. As we are just embarking on the search for life on Mars and preparing the design of a 2020 rover mission, there are still many uncertainties about life’s distribution in hyperarid environment, including on our own planet. Therefore, an exploration strategy that could both multiply the number of sites to be visited per mission through mobility and provide subsurface access may give us initially a greater statistical chance of success of finding life. Project Overall Goal. The Life in the Atacama (LITA) project is funded by the NASA ASTEP program (2011-2014). Its overarching goal is to demonstrate, in realistic mission configurations, autonomous operations of a rover-mounted drill that could access and interrogate the martian subsurface using in situ and remote instrumentation, and could cover long distances to document a diversity of environments. This analog mission takes place in the Atacama desert of Chile along an arid-hyperarid-arid transect that runs from the Coastal Range to the Andes. It provides the background data to critically perform a quantitative assessment of such strategy. Over that transect, LITA seeks evidence of past and present life and habitats down to 1-m depth, in the process drilling through the three major boundaries identified from microbial life by previous Atacama soil studies [e.g., 3-5]. Further, the geological diversity of the traverse that includes desert pavement, volcanic, hydrothermal, playa, channel, gully, lag and aeolian deposits, and soils of varied cohesiveness and hardness provide a unique opportunity to test and quantify the response of the rover-drill system in each specific environment, and to accumulate critical operational data for future planetary missions (Fig. 1)