ANALYSIS OF AUTONOMOUS ROBOTIC CORE MATERIALS BY THE MARS MICROBEAM RAMAN SPECTROMETER (MMRS) DURING THE “LIFE IN THE ATACAMA” 2013 ROVER FIELD CAMPAIGN IN CHILE

Laser Raman spectroscopy (LRS) is a powerful technique for the detection and characterization of molecular species, such as minerals, reduced carbons, and biomarkers during planetary surface exploration. LRS measurements are non-destructive and non-invasive, thus the planetary materials can be interrogated in situ. The LRS spectral peaks are relatively sharp and separated from each other, allowing the distinction of major, minor and trace species in a mixture (rocks and soils) in raw LRS spectra.

A LRS for flight, the Mars Microbeam Raman Spectrometer (MMRS), has been developed by a combined team at Washington University in St. Louis and at Jet Propulsion Laboratory, supported by NASA PIDDP, MIDP, and MatISSE programs. Since 2012, MMRS team has joined a NASA ASTEP project, to conduct a science investigation of subsurface mineralogical environment at Atacama Desert.

In June 2013, the Life in the Atacama project funded by the NASA ASTEP program and led by the Carnegie Mellon University Robotics Institute deployed a rover named Zöe in the Atacama Desert, Chile. The field exploration was remotely directed by a science team in US, and locally supervised by an engineering team at Atacama. The MMRS was integrated onto the rover. Over 3000 Raman spectra were taken for surface and subsurface samples at Atacama. They were collected either by a robotic drill mounted on Zoë, or by human for ground-truth at various depths, from surface to 80 cm. Rover, drill, and MMRS operations were autonomous to provide realistic mission operations. Seven sampling sites along Zoë’s traverse (~50 km) were selected, that covered fluvial fan, mountain slope, and a playa. During 12 days of field operation, the MMRS system demonstrated an overall robust performance in optical alignment and spectra quality, including on very rough terrains. MMRS measurements were taken during daytime and evening time, and during Zoë’s traverses. The preliminary data analysis shows that a variety of minerals were successfully identified, such as quartz and feldspar in surface materials, and TiO₂, FeOOH, CaSO₄·2H₂O, CaSO₄, CaCO₃, BaCO₃, and potential MgSO₄.4H₂O in subsurface materials. A comprehensive list of the compounds detected and their distributions at different sites and depths will be presented, as well as the lessons learned regarding field operations.